Added Irrlicht 1.8, but without all the Windows binaries.

author: David Walter Seikel 2013-01-13 17:24:39 +1000
committer: David Walter Seikel 2013-01-13 17:24:39 +1000
commit: 393b5cd1dc438872af89d334ef6e5fcc59f27d47 (patch)
tree: 6a14521219942a08a1b95cb2f5a923a9edd60f63 /libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib
parent: Add a note about rasters suggested start up code. (diff)
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diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/README.txt b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/README.txt
new file mode 100644
index 0000000..7e9b7d0
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/README.txt
@@ -0,0 +1,4 @@
+This "contrib" directory contains contributions which are not necessarily under
+the libpng license, although all are open source.  They are not part of
+libpng proper and are not used for building the library.
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/COPYING b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/COPYING
new file mode 100644
index 0000000..c2d382b
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/COPYING
@@ -0,0 +1,340 @@
+                    GNU GENERAL PUBLIC LICENSE
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diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/LICENSE b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/LICENSE
new file mode 100644
index 0000000..40a0c8e
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/LICENSE
@@ -0,0 +1,50 @@
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.mingw32 b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.mingw32
new file mode 100644
index 0000000..a736556
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.mingw32
@@ -0,0 +1,130 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using mingw32-gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#       The programs built by this makefile are described in the book,
+#       "PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#       Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#       generally for sale anymore, but it's the thought that counts,
+#       right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS-prompt window via:
+#
+#       make -f Makefile.mingw32
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGDIR and ZDIR macros below).  It makes no assumptions
+# at all about the mingw32 installation tree (W32DIR).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds both statically and dynamically linked executables by default.
+# (You need only one set, but for testing it can be handy to have both.)
+# macros --------------------------------------------------------------------
+#PNGDIR = ../..#                for libpng-x.y.z/contrib/gregbook builds
+PNGDIR = ../libpng-win32
+PNGINC = -I$(PNGDIR)
+PNGLIBd = $(PNGDIR)/libpng.dll.a        # dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a            # statically linked, local libpng
+#ZDIR = ../../../zlib-win32#    for libpng-x.y.z/contrib/gregbook builds
+ZDIR = ../zlib-win32
+ZINC = -I$(ZDIR)
+ZLIBd = $(ZDIR)/libzdll.a
+ZLIBs = $(ZDIR)/libz.a
+# change this to be the path where mingw32 installs its stuff:
+W32DIR =
+#W32DIR = /usr/local/cross-tools/i386-mingw32msvc
+W32INC = -I$(W32DIR)/include
+W32LIB = $(W32DIR)/lib/libuser32.a $(W32DIR)/lib/libgdi32.a
+CC = gcc
+#CC = i386-mingw32msvc-gcc #    e.g., Linux -> Win32 cross-compilation
+LD = $(CC)
+RM = rm -f
+CFLAGS = -O -Wall $(INCS) $(MINGW_CCFLAGS)
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic and -W can also be used]
+LDFLAGS = $(MINGW_LDFLAGS)
+O = .o
+E = .exe
+INCS = $(PNGINC) $(ZINC) $(W32INC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(W32LIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(W32LIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd)
+WLIBSs = $(PNGLIBs) $(ZLIBs)
+RPNG   = rpng-win
+RPNG2  = rpng2-win
+WPNG   = wpng
+ROBJSd  = $(RPNG)$(O) readpng.pic$(O)
+ROBJS2d = $(RPNG2)$(O) readpng2.pic$(O)
+WOBJSd  = $(WPNG)$(O) writepng.pic$(O)
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+ROBJSs  = $(RPNG)$(O) readpng$(O)
+ROBJS2s = $(RPNG2)$(O) readpng2$(O)
+WOBJSs  = $(WPNG)$(O) writepng$(O)
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+%.pic$(O): %.c
+        $(CC) -c $(CFLAGS) -DPNG_BUILD_DLL -o $@ $<
+# dependencies --------------------------------------------------------------
+all:  $(EXES)
+$(RPNGs)$(E): $(ROBJSs)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJSs) $(RLIBSs)
+$(RPNG)$(E): $(ROBJSd)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJSd) $(RLIBSd)
+$(RPNG2s)$(E): $(ROBJS2s)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS2s) $(RLIBSs)
+$(RPNG2)$(E): $(ROBJS2d)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS2d) $(RLIBSd)
+$(WPNGs)$(E): $(WOBJSs)
+        $(LD) $(LDFLAGS) -o $@ $(WOBJSs) $(WLIBSs)
+$(WPNG)$(E): $(WOBJSd)
+        $(LD) $(LDFLAGS) -o $@ $(WOBJSd) $(WLIBSd)
+$(RPNG)$(O):    $(RPNG).c readpng.h
+$(RPNG2)$(O):   $(RPNG2).c readpng2.h
+$(WPNG)$(O):    $(WPNG).c writepng.h
+readpng$(O) readpng.pic$(O):    readpng.c readpng.h
+readpng2$(O) readpng2.pic$(O):  readpng2.c readpng2.h
+writepng$(O) writepng.pic$(O):  writepng.c writepng.h
+# maintenance ---------------------------------------------------------------
+clean:
+        $(RM) $(EXES)
+        $(RM) $(ROBJSs) $(ROBJS2s) $(WOBJSs)
+        $(RM) $(ROBJSd) $(ROBJS2d) $(WOBJSd)
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.sgi b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.sgi
new file mode 100644
index 0000000..8773a00
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.sgi
@@ -0,0 +1,104 @@
+# Sample makefile for rpng-x / rpng2-x / wpng for SGI using cc and make.
+# Greg Roelofs
+# Last modified:  7 March 2002
+#
+#       The programs built by this makefile are described in the book,
+#       "PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#       Associates, 1999).  Go buy a copy, eh?  Buy some for friends
+#       and family, too.  (Not that this is a blatant plug or anything.)
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#       make -f Makefile.sgi
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are both installed in /usr/local/{include,lib} (as indicated by the
+# PNG* and Z* macros below).  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIB, ZINC and ZLIB lines.
+#
+# This makefile builds dynamically linked executables (against libpng and zlib,
+# that is), but that can be changed by uncommenting the appropriate PNGLIB and
+# ZLIB lines.
+# macros --------------------------------------------------------------------
+PNGINC = -I/usr/local/include/libpng15
+PNGLIB = -L/usr/local/lib -lpng15         # dynamically linked against libpng
+#PNGLIB = /usr/local/lib/libpng15.a # statically linked against libpng
+# or:
+#PNGINC = -I../..
+#PNGLIB = -L../.. -lpng
+#PNGLIB = ../../libpng.a
+ZINC = -I/usr/local/include
+ZLIB = -L/usr/local/lib -lz             # dynamically linked against zlib
+#ZLIB = /usr/local/lib/libz.a           # statically linked against zlib
+#ZINC = -I../zlib
+#ZLIB = -L../zlib -lz
+#ZLIB = ../../../zlib/libz.a
+XINC = -I/usr/include/X11               # old-style, stock X distributions
+XLIB = -L/usr/lib/X11 -lX11
+#XINC = -I/usr/openwin/include          # Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+#XINC = -I/usr/X11R6/include            # new X distributions (XFree86, etc.)
+#XLIB = -L/usr/X11R6/lib -lX11
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(XLIB) -lm
+WLIBS = $(PNGLIB) $(ZLIB)
+CC = cc
+LD = cc
+RM = rm -f
+# ABI must be the same as that used to build libpng.
+ABI=
+CFLAGS = $(ABI) -O -fullwarn $(INCS)
+LDFLAGS = $(ABI)
+O = .o
+E =
+RPNG  = rpng-x
+RPNG2 = rpng2-x
+WPNG  = wpng
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies --------------------------------------------------------------
+all:  $(EXES)
+$(RPNG)$(E): $(ROBJS)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBS)
+$(RPNG2)$(E): $(ROBJS2)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBS)
+$(WPNG)$(E): $(WOBJS)
+        $(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBS)
+$(RPNG)$(O):    $(RPNG).c readpng.h
+$(RPNG2)$(O):   $(RPNG2).c readpng2.h
+$(WPNG)$(O):    $(WPNG).c writepng.h
+readpng$(O):    readpng.c readpng.h
+readpng2$(O):   readpng2.c readpng2.h
+writepng$(O):   writepng.c writepng.h
+# maintenance ---------------------------------------------------------------
+clean:
+        $(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.unx b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.unx
new file mode 100644
index 0000000..3bffc2f
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.unx
@@ -0,0 +1,132 @@
+# Sample makefile for rpng-x / rpng2-x / wpng using gcc and make.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#       The programs built by this makefile are described in the book,
+#       "PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#       Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#       generally for sale anymore, but it's the thought that counts,
+#       right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a shell prompt in the usual way; for example:
+#
+#       make -f Makefile.unx
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are installed in /usr/local/{include,lib} or as otherwise indicated by
+# the PNG* and Z* macros below.  Edit as appropriate--choose only ONE each of
+# the PNGINC, PNGLIBd, PNGLIBs, ZINC, ZLIBd and ZLIBs lines.
+#
+# This makefile builds both dynamically and statically linked executables
+# (against libpng and zlib, that is), but that can be changed by modifying
+# the "EXES =" line.  (You need only one set, but for testing it can be handy
+# to have both.)
+# macros --------------------------------------------------------------------
+#PNGDIR = /usr/local/lib
+#PNGINC = -I/usr/local/include/libpng15
+#PNGLIBd = -L$(PNGDIR) -lpng15 # dynamically linked, installed libpng
+#PNGLIBs = $(PNGDIR)/libpng15.a # statically linked, installed libpng
+# or:
+PNGDIR = ../..# this one is for libpng-x.y.z/contrib/gregbook builds
+#PNGDIR = ../libpng
+PNGINC = -I$(PNGDIR)
+PNGLIBd = -Wl,-rpath,$(PNGDIR) -L$(PNGDIR) -lpng15      # dynamically linked
+PNGLIBs = $(PNGDIR)/libpng.a            # statically linked, local libpng
+ZDIR = /usr/local/lib
+#ZDIR = /usr/lib64
+ZINC = -I/usr/local/include
+ZLIBd = -L$(ZDIR) -lz                   # dynamically linked against zlib
+ZLIBs = $(ZDIR)/libz.a                  # statically linked against zlib
+# or:
+#ZDIR = ../zlib
+#ZINC = -I$(ZDIR)
+#ZLIBd = -Wl,-rpath,$(ZDIR) -L$(ZDIR) -lz  # -rpath allows in-place testing
+#ZLIBs = $(ZDIR)/libz.a
+#XINC = -I/usr/include                  # old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11            #  (including SGI IRIX)
+#XINC = -I/usr/openwin/include          # Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+XINC = -I/usr/X11R6/include             # new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11        # e.g., Red Hat on AMD64
+INCS = $(PNGINC) $(ZINC) $(XINC)
+RLIBSd = $(PNGLIBd) $(ZLIBd) $(XLIB) -lm
+RLIBSs = $(PNGLIBs) $(ZLIBs) $(XLIB) -lm
+WLIBSd = $(PNGLIBd) $(ZLIBd) -lm
+WLIBSs = $(PNGLIBs) $(ZLIBs)
+CC = gcc
+LD = gcc
+RM = rm -f
+CFLAGS = -O -Wall $(INCS) -DFEATURE_LOOP
+# [note that -Wall is a gcc-specific compilation flag ("most warnings on")]
+# [-ansi, -pedantic and -W can also be used]
+LDFLAGS =
+O = .o
+E =
+RPNG   = rpng-x
+RPNG2  = rpng2-x
+WPNG   = wpng
+RPNGs  = $(RPNG)-static
+RPNG2s = $(RPNG2)-static
+WPNGs  = $(WPNG)-static
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+STATIC_EXES  = $(RPNGs)$(E) $(RPNG2s)$(E) $(WPNGs)$(E)
+DYNAMIC_EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+EXES = $(STATIC_EXES) $(DYNAMIC_EXES)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies --------------------------------------------------------------
+all:  $(EXES)
+$(RPNGs)$(E): $(ROBJS)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSs)
+$(RPNG)$(E): $(ROBJS)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS) $(RLIBSd)
+$(RPNG2s)$(E): $(ROBJS2)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSs)
+$(RPNG2)$(E): $(ROBJS2)
+        $(LD) $(LDFLAGS) -o $@ $(ROBJS2) $(RLIBSd)
+$(WPNGs)$(E): $(WOBJS)
+        $(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSs)
+$(WPNG)$(E): $(WOBJS)
+        $(LD) $(LDFLAGS) -o $@ $(WOBJS) $(WLIBSd)
+$(RPNG)$(O):    $(RPNG).c readpng.h
+$(RPNG2)$(O):   $(RPNG2).c readpng2.h
+$(WPNG)$(O):    $(WPNG).c writepng.h
+readpng$(O):    readpng.c readpng.h
+readpng2$(O):   readpng2.c readpng2.h
+writepng$(O):   writepng.c writepng.h
+# maintenance ---------------------------------------------------------------
+clean:
+        $(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.w32 b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.w32
new file mode 100644
index 0000000..eced083
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/Makefile.w32
@@ -0,0 +1,113 @@
+# Sample makefile for rpng-win / rpng2-win / wpng using MSVC and NMAKE.
+# Greg Roelofs
+# Last modified:  2 June 2007
+#
+#       The programs built by this makefile are described in the book,
+#       "PNG:  The Definitive Guide," by Greg Roelofs (O'Reilly and
+#       Associates, 1999).  Go buy a copy, eh?  Well, OK, it's not
+#       generally for sale anymore, but it's the thought that counts,
+#       right?  (Hint:  http://www.libpng.org/pub/png/book/ )
+#
+# Invoke this makefile from a DOS prompt window via:
+#
+#       %devstudio%\vc\bin\vcvars32.bat
+#       nmake -nologo -f Makefile.w32
+#
+# where %devstudio% is the installation directory for MSVC / DevStudio.  If
+# you get "environment out of space" errors, create a desktop shortcut with
+# "c:\windows\command.com /e:4096" as the program command line and set the
+# working directory to this directory.  Then double-click to open the new
+# DOS-prompt window with a bigger environment and retry the commands above.
+#
+# This makefile assumes libpng and zlib have already been built or downloaded
+# and are in subdirectories at the same level as the current subdirectory
+# (as indicated by the PNGPATH and ZPATH macros below).  Edit as appropriate.
+#
+# Note that the names of the dynamic and static libpng and zlib libraries
+# used below may change in later releases of the libraries.  This makefile
+# builds statically linked executables, but that can be changed by uncom-
+# menting the appropriate PNGLIB and ZLIB lines.
+!include <ntwin32.mak>
+# macros --------------------------------------------------------------------
+PNGPATH = ../libpng
+PNGINC = -I$(PNGPATH)
+#PNGLIB = $(PNGPATH)/pngdll.lib
+PNGLIB = $(PNGPATH)/libpng.lib
+ZPATH = ../zlib
+ZINC = -I$(ZPATH)
+#ZLIB = $(ZPATH)/zlibdll.lib
+ZLIB = $(ZPATH)/zlibstat.lib
+WINLIBS = -defaultlib:user32.lib gdi32.lib
+# ["real" apps may also need comctl32.lib, comdlg32.lib, winmm.lib, etc.]
+INCS = $(PNGINC) $(ZINC)
+RLIBS = $(PNGLIB) $(ZLIB) $(WINLIBS)
+WLIBS = $(PNGLIB) $(ZLIB)
+CC = cl
+LD = link
+RM = del
+CFLAGS = -nologo -O -W3 $(INCS) $(cvars)
+# [note that -W3 is an MSVC-specific compilation flag ("all warnings on")]
+# [see %devstudio%\vc\include\win32.mak for cvars macro definition]
+O = .obj
+E = .exe
+RLDFLAGS = -nologo -subsystem:windows
+WLDFLAGS = -nologo
+RPNG  = rpng-win
+RPNG2 = rpng2-win
+WPNG  = wpng
+ROBJS  = $(RPNG)$(O) readpng$(O)
+ROBJS2 = $(RPNG2)$(O) readpng2$(O)
+WOBJS  = $(WPNG)$(O) writepng$(O)
+EXES = $(RPNG)$(E) $(RPNG2)$(E) $(WPNG)$(E)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies --------------------------------------------------------------
+all:  $(EXES)
+$(RPNG)$(E): $(ROBJS)
+        $(LD) $(RLDFLAGS) -out:$@ $(ROBJS) $(RLIBS)
+$(RPNG2)$(E): $(ROBJS2)
+        $(LD) $(RLDFLAGS) -out:$@ $(ROBJS2) $(RLIBS)
+$(WPNG)$(E): $(WOBJS)
+        $(LD) $(WLDFLAGS) -out:$@ $(WOBJS) $(WLIBS)
+$(RPNG)$(O):    $(RPNG).c readpng.h
+$(RPNG2)$(O):   $(RPNG2).c readpng2.h
+$(WPNG)$(O):    $(WPNG).c writepng.h
+readpng$(O):    readpng.c readpng.h
+readpng2$(O):   readpng2.c readpng2.h
+writepng$(O):   writepng.c writepng.h
+# maintenance ---------------------------------------------------------------
+clean:
+#       ideally we could just do this:
+#       $(RM) $(EXES) $(ROBJS) $(ROBJS2) $(WOBJS)
+#       ...but the Windows "DEL" command is none too bright, so:
+        $(RM) r*$(E)
+        $(RM) w*$(E)
+        $(RM) r*$(O)
+        $(RM) w*$(O)
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/README b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/README
new file mode 100644
index 0000000..791fec8
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/README
@@ -0,0 +1,186 @@
+                     ===========================
+                      PNG: The Definitive Guide
+                     ===========================
+                             Source Code
+Chapters 13, 14 and 15 of "PNG: The Definitive Guide" discuss three free,
+cross-platform demo programs that show how to use the libpng reference
+library:  rpng, rpng2 and wpng.  rpng and rpng2 are viewers; the first is
+a very simple example that that shows how a standard file-viewer might use
+libpng, while the second is designed to process streaming data and shows
+how a web browser might be written.  wpng is a simple command-line program
+that reads binary PGM and PPM files (the ``raw'' grayscale and RGB subsets
+of PBMPLUS/NetPBM) and converts them to PNG.
+The source code for all three demo programs currently compiles under
+Unix, OpenVMS, and 32-bit Windows.  (Special thanks to Martin Zinser,
+zinser@decus.de, for making the necessary changes for OpenVMS and for
+providing an appropriate build script.)  Build instructions can be found
+below.
+Files:
+   README             this file
+   LICENSE            terms of distribution and reuse (BSD-like or GNU GPL)
+   COPYING            GNU General Public License (GPL)
+   Makefile.unx       Unix makefile
+   Makefile.w32       Windows (MSVC) makefile
+   makevms.com        OpenVMS build script
+   rpng-win.c         Windows front end for the basic viewer
+   rpng-x.c           X Window System (Unix, OpenVMS) front end
+   readpng.c          generic back end for the basic viewer
+   readpng.h          header file for the basic viewer
+   rpng2-win.c        Windows front end for the progressive viewer
+   rpng2-x.c          X front end for the progressive viewer
+   readpng2.c         generic back end for the progressive viewer
+   readpng2.h         header file for the progressive viewer
+   wpng.c             generic (text) front end for the converter
+   writepng.c         generic back end for the converter
+   writepng.h         header file for the converter
+   toucan.png         transparent PNG for testing (by Stefan Schneider)
+Note that, although the programs are designed to be functional, their
+primary purpose is to illustrate how to use libpng to add PNG support to
+other programs.  As such, their user interfaces are crude and definitely
+are not intended for everyday use.
+Please see http://www.libpng.org/pub/png/pngbook.html for further infor-
+mation and links to the latest version of the source code, and Chapters
+13-15 of the book for detailed discussion of the three programs.
+Greg Roelofs
+http://pobox.com/~newt/greg_contact.html
+16 March 2008
+BUILD INSTRUCTIONS
+ - Prerequisites (in order of compilation):
+      - zlib            http://zlib.net/
+      - libpng          http://www.libpng.org/pub/png/libpng.html
+      - pngbook         http://www.libpng.org/pub/png/book/sources.html
+     The pngbook demo programs are explicitly designed to demonstrate proper
+     coding techniques for using the libpng reference library.  As a result,
+     you need to download and build both zlib (on which libpng depends) and
+     libpng.  A common build setup is to place the zlib, libpng and pngbook
+     subdirectory trees ("folders") in the same parent directory.  Then the
+     libpng build can refer to files in ../zlib (or ..\zlib or [-.zlib]),
+     and similarly for the pngbook build.
+     Note that all three packages are designed to be built from a command
+     line by default; those who wish to use a graphical or other integrated
+     development environments are on their own.
+ - Unix:
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a directory and change into that directory.
+     Copy Makefile.unx to Makefile and edit the PNG* and Z* variables
+     appropriately (possibly also the X* variables if necessary).
+     make
+     There is no "install" target, so copy the three executables somewhere
+     in your path or run them from the current directory.  All three will
+     print a basic usage screen when run without any command-line arguments;
+     see the book for more details.
+ - Windows:
+     Unpack the latest pngbook sources (which should correspond to this
+     README file) into a folder, open a "DOS shell" or "command prompt"
+     or equivalent command-line window, and cd into the folder where you
+     unpacked the source code.
+     For MSVC, set up the necessary environment variables by invoking
+        %devstudio%\vc\bin\vcvars32.bat
+     where where %devstudio% is the installation directory for MSVC /
+     DevStudio.  If you get "environment out of space" errors under 95/98,
+     create a desktop shortcut with "c:\windows\command.com /e:4096" as
+     the program command line and set the working directory to the pngbook
+     directory.  Then double-click to open the new DOS-prompt window with
+     a bigger environment and retry the commands above.
+     Copy Makefile.w32 to Makefile and edit the PNGPATH and ZPATH variables
+     appropriately (possibly also the "INC" and "LIB" variables if needed).
+     Note that the names of the dynamic and static libpng and zlib libraries
+     used in the makefile may change in later releases of the libraries.
+     Also note that, as of libpng version 1.0.5, MSVC DLL builds do not work.
+     This makefile therefore builds statically linked executables, but if
+     the DLL problems ever get fixed, uncommenting the appropriate PNGLIB
+     and ZLIB lines will build dynamically linked executables instead.
+     Do the build by typing
+        nmake
+     The result should be three executables:  rpng-win.exe, rpng2-win.exe,
+     and wpng.exe.  Copy them somewhere in your PATH or run them from the
+     current folder.  Like the Unix versions, the two windowed programs
+     (rpng and rpng2) now display a usage screen in a console window when
+     invoked without command-line arguments; this is new behavior as of
+     the June 2001 release.  Note that the programs use the Unix-style "-"
+     character to specify options, instead of the more common DOS/Windows
+     "/" character.  (For example:  "rpng2-win -bgpat 4 foo.png", not
+     "rpng2-win /bgpat 4 foo.png")
+ - OpenVMS:
+     Unpack the pngbook sources into a subdirectory and change into that
+     subdirectory.
+     Edit makevms.com appropriately, specifically the zpath and pngpath
+     variables.
+     @makevms
+     To run the programs, they probably first need to be set up as "foreign
+     symbols," with "disk" and "dir" set appropriately:
+     $ rpng  == "$disk:[dir]rpng-x.exe"
+     $ rpng2 == "$disk:[dir]rpng2-x.exe"
+     $ wpng  == "$disk:[dir]wpng.exe"
+     All three will print a basic usage screen when run without any command-
+     line arguments; see the book for more details.  Note that the options
+     style is Unix-like, i.e., preceded by "-" rather than "/".
+RUNNING THE PROGRAMS:  (VERY) BRIEF INTRO
+     rpng is a simple PNG viewer that can display transparent PNGs with a
+     specified background color; for example,
+        rpng -bgcolor \#ff0000 toucan.png
+     would display the image with a red background.  rpng2 is a progressive
+     viewer that simulates a web browser in some respects; it can display
+     images against either a background color or a dynamically generated
+     background image.  For example:
+        rpng2 -bgpat 16 toucan.png
+     wpng is a purely command-line image converter from binary PBMPLUS/NetPBM
+     format (.pgm or .ppm) to PNG; for example,
+        wpng -time < toucan-notrans.ppm > toucan-notrans.png
+     would convert the specified PPM file (using redirection) to PNG, auto-
+     matically setting the PNG modification-time chunk.
+     All options can be abbreviated to the shortest unique value; for example,
+     "-bgc" for -bgcolor (versus "-bgp" for -bgpat), or "-g" for -gamma.
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/makevms.com b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/makevms.com
new file mode 100644
index 0000000..29a5727
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/makevms.com
@@ -0,0 +1,132 @@
+$!------------------------------------------------------------------------------
+$! make "PNG: The Definitive Guide" demo programs (for X) under OpenVMS
+$!
+$! Script created by Martin Zinser for libpng; modified by Greg Roelofs
+$! for standalone pngbook source distribution.
+$!
+$!
+$!    Set locations where zlib and libpng sources live.
+$!
+$ zpath   = ""
+$ pngpath = ""
+$!
+$ if f$search("[---.zlib]zlib.h").nes."" then zpath = "[---.zlib]"
+$ if f$search("[--]png.h").nes."" then pngpath = "[--]"
+$!
+$ if f$search("[-.zlib]zlib.h").nes."" then zpath = "[-.zlib]"
+$ if f$search("[-.libpng]png.h").nes."" then pngpath = "[-.libpng]"
+$!
+$ if zpath .eqs. ""
+$ then
+$   write sys$output "zlib include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$ if pngpath .eqs. ""
+$ then
+$   write sys$output "libpng include not found. Exiting..."
+$   exit 2
+$ endif
+$!
+$!    Look for the compiler used.
+$!
+$ ccopt="/include=(''zpath',''pngpath')"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "''pngpath'libpng.olb/lib"
+$ write lopt "''zpath'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$!
+$!    Build 'em.
+$!
+$ write sys$output "Compiling PNG book programs ..."
+$   CALL MAKE readpng.OBJ "cc ''CCOPT' readpng" -
+        readpng.c readpng.h
+$   CALL MAKE readpng2.OBJ "cc ''CCOPT' readpng2" -
+        readpng2.c readpng2.h
+$   CALL MAKE writepng.OBJ "cc ''CCOPT' writepng" -
+        writepng.c writepng.h
+$   write sys$output "Building rpng-x..."
+$   CALL MAKE rpng-x.OBJ "cc ''CCOPT' rpng-x" -
+        rpng-x.c readpng.h
+$   call make rpng-x.exe -
+        "LINK rpng-x,readpng,lib.opt/opt,x11.opt/opt" -
+        rpng-x.obj readpng.obj
+$   write sys$output "Building rpng2-x..."
+$   CALL MAKE rpng2-x.OBJ "cc ''CCOPT' rpng2-x" -
+        rpng2-x.c readpng2.h
+$   call make rpng2-x.exe -
+        "LINK rpng2-x,readpng2,lib.opt/opt,x11.opt/opt" -
+        rpng2-x.obj readpng2.obj
+$   write sys$output "Building wpng..."
+$   CALL MAKE wpng.OBJ "cc ''CCOPT' wpng" -
+        wpng.c writepng.h
+$   call make wpng.exe -
+        "LINK wpng,writepng,lib.opt/opt" -
+        wpng.obj writepng.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.c
new file mode 100644
index 0000000..27a2f11
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.c
@@ -0,0 +1,311 @@
+/*---------------------------------------------------------------------------
+   rpng - simple PNG display program                              readpng.c
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#include <stdio.h>
+#include <stdlib.h>
+#include "png.h"        /* libpng header; includes zlib.h */
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+/* future versions of libpng will provide this macro: */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr)   ((png_ptr)->jmpbuf)
+#endif
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+png_uint_32  width, height;
+int  bit_depth, color_type;
+uch  *image_data = NULL;
+void readpng_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    uch sig[8];
+    /* first do a quick check that the file really is a PNG image; could
+     * have used slightly more general png_sig_cmp() function instead */
+    fread(sig, 1, 8, infile);
+    if (png_sig_cmp(sig, 0, 8))
+        return 1;   /* bad signature */
+    /* could pass pointers to user-defined error handlers instead of NULLs: */
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+    png_init_io(png_ptr, infile);
+    png_set_sig_bytes(png_ptr, 8);  /* we already read the 8 signature bytes */
+    png_read_info(png_ptr, info_ptr);  /* read all PNG info up to image data */
+    /* alternatively, could make separate calls to png_get_image_width(),
+     * etc., but want bit_depth and color_type for later [don't care about
+     * compression_type and filter_type => NULLs] */
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+      NULL, NULL, NULL);
+    *pWidth = width;
+    *pHeight = height;
+    /* OK, that's all we need for now; return happy */
+    return 0;
+}
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    png_color_16p pBackground;
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+    if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+        return 1;
+    /* it is not obvious from the libpng documentation, but this function
+     * takes a pointer to a pointer, and it always returns valid red, green
+     * and blue values, regardless of color_type: */
+    png_get_bKGD(png_ptr, info_ptr, &pBackground);
+    /* however, it always returns the raw bKGD data, regardless of any
+     * bit-depth transformations, so check depth and adjust if necessary */
+    if (bit_depth == 16) {
+        *red   = pBackground->red   >> 8;
+        *green = pBackground->green >> 8;
+        *blue  = pBackground->blue  >> 8;
+    } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+        if (bit_depth == 1)
+            *red = *green = *blue = pBackground->gray? 255 : 0;
+        else if (bit_depth == 2)
+            *red = *green = *blue = (255/3) * pBackground->gray;
+        else /* bit_depth == 4 */
+            *red = *green = *blue = (255/15) * pBackground->gray;
+    } else {
+        *red   = (uch)pBackground->red;
+        *green = (uch)pBackground->green;
+        *blue  = (uch)pBackground->blue;
+    }
+    return 0;
+}
+/* display_exponent == LUT_exponent * CRT_exponent */
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    double  gamma;
+    png_uint_32  i, rowbytes;
+    png_bytepp  row_pointers = NULL;
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+    /* unlike the example in the libpng documentation, we have *no* idea where
+     * this file may have come from--so if it doesn't have a file gamma, don't
+     * do any correction ("do no harm") */
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, display_exponent, gamma);
+    /* all transformations have been registered; now update info_ptr data,
+     * get rowbytes and channels, and allocate image memory */
+    png_read_update_info(png_ptr, info_ptr);
+    *pRowbytes = rowbytes = png_get_rowbytes(png_ptr, info_ptr);
+    *pChannels = (int)png_get_channels(png_ptr, info_ptr);
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return NULL;
+    }
+    if ((row_pointers = (png_bytepp)malloc(height*sizeof(png_bytep))) == NULL) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        free(image_data);
+        image_data = NULL;
+        return NULL;
+    }
+    Trace((stderr, "readpng_get_image:  channels = %d, rowbytes = %ld, height = %ld\n",
+        *pChannels, rowbytes, height));
+    /* set the individual row_pointers to point at the correct offsets */
+    for (i = 0;  i < height;  ++i)
+        row_pointers[i] = image_data + i*rowbytes;
+    /* now we can go ahead and just read the whole image */
+    png_read_image(png_ptr, row_pointers);
+    /* and we're done!  (png_read_end() can be omitted if no processing of
+     * post-IDAT text/time/etc. is desired) */
+    free(row_pointers);
+    row_pointers = NULL;
+    png_read_end(png_ptr, NULL);
+    return image_data;
+}
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+    if (png_ptr && info_ptr) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        png_ptr = NULL;
+        info_ptr = NULL;
+    }
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.h
new file mode 100644
index 0000000..ec6b483
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng.h
@@ -0,0 +1,88 @@
+/*---------------------------------------------------------------------------
+   rpng - simple PNG display program                              readpng.h
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+/* prototypes for public functions in readpng.c */
+void readpng_version_info(void);
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight);
+int readpng_get_bgcolor(uch *bg_red, uch *bg_green, uch *bg_blue);
+uch *readpng_get_image(double display_exponent, int *pChannels,
+                       ulg *pRowbytes);
+void readpng_cleanup(int free_image_data);
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.c
new file mode 100644
index 0000000..3bbd2ec
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.c
@@ -0,0 +1,511 @@
+/*---------------------------------------------------------------------------
+   rpng2 - progressive-model PNG display program                 readpng2.c
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#include <stdlib.h>     /* for exit() prototype */
+#include <setjmp.h>
+#include <zlib.h>
+#include "png.h"        /* libpng header from the local directory */
+#include "readpng2.h"   /* typedefs, common macros, public prototypes */
+/* local prototypes */
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                 png_uint_32 row_num, int pass);
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr);
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg);
+void readpng2_version_info(void)
+{
+    fprintf(stderr, "   Compiled with libpng %s; using libpng %s\n",
+      PNG_LIBPNG_VER_STRING, png_libpng_ver);
+    fprintf(stderr, "   and with zlib %s; using zlib %s.\n",
+      ZLIB_VERSION, zlib_version);
+}
+int readpng2_check_sig(uch *sig, int num)
+{
+    return !png_sig_cmp(sig, 0, num);
+}
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory */
+int readpng2_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+      readpng2_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        return 4;   /* out of memory */
+    }
+    /* we could create a second info struct here (end_info), but it's only
+     * useful if we want to keep pre- and post-IDAT chunk info separated
+     * (mainly for PNG-aware image editors and converters) */
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or exit immediately, so here we are: */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        return 2;
+    }
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+    /* prepare the reader to ignore all recognized chunks whose data won't be
+     * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT,
+     * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */
+    {
+        /* These byte strings were copied from png.h.  If a future libpng
+         * version recognizes more chunks, add them to this list.  If a
+         * future version of readpng2.c recognizes more chunks, delete them
+         * from this list. */
+        static /* const */ png_byte chunks_to_ignore[] = {
+             99,  72,  82,  77, '\0',  /* cHRM */
+            104,  73,  83,  84, '\0',  /* hIST */
+            105,  67,  67,  80, '\0',  /* iCCP */
+            105,  84,  88, 116, '\0',  /* iTXt */
+            111,  70,  70, 115, '\0',  /* oFFs */
+            112,  67,  65,  76, '\0',  /* pCAL */
+            112,  72,  89, 115, '\0',  /* pHYs */
+            115,  66,  73,  84, '\0',  /* sBIT */
+            115,  67,  65,  76, '\0',  /* sCAL */
+            115,  80,  76,  84, '\0',  /* sPLT */
+            115,  84,  69,  82, '\0',  /* sTER */
+            116,  69,  88, 116, '\0',  /* tEXt */
+            116,  73,  77,  69, '\0',  /* tIME */
+            122,  84,  88, 116, '\0'   /* zTXt */
+        };
+        png_set_keep_unknown_chunks(png_ptr, 1 /* PNG_HANDLE_CHUNK_NEVER */,
+          chunks_to_ignore, sizeof(chunks_to_ignore)/5);
+    }
+#endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
+    /* instead of doing png_init_io() here, now we set up our callback
+     * functions for progressive decoding */
+    png_set_progressive_read_fn(png_ptr, mainprog_ptr,
+      readpng2_info_callback, readpng2_row_callback, readpng2_end_callback);
+    /* make sure we save our pointers for use in readpng2_decode_data() */
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+    /* and that's all there is to initialization */
+    return 0;
+}
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    /* setjmp() must be called in every function that calls a PNG-reading
+     * libpng function */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+    /* hand off the next chunk of input data to libpng for decoding */
+    png_process_data(png_ptr, info_ptr, rawbuf, length);
+    return 0;
+}
+static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+    int  color_type, bit_depth;
+    png_uint_32 width, height;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    double  gamma;
+#else
+    png_fixed_point gamma;
+#endif
+    /* setjmp() doesn't make sense here, because we'd either have to exit(),
+     * longjmp() ourselves, or return control to libpng, which doesn't want
+     * to see us again.  By not doing anything here, libpng will instead jump
+     * to readpng2_decode_data(), which can return an error value to the main
+     * program. */
+    /* retrieve the pointer to our special-purpose struct, using the png_ptr
+     * that libpng passed back to us (i.e., not a global this time--there's
+     * no real difference for a single image, but for a multithreaded browser
+     * decoding several PNG images at the same time, one needs to avoid mixing
+     * up different images' structs) */
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we be hosed */
+        fprintf(stderr,
+          "readpng2 error:  main struct not recoverable in info_callback.\n");
+        fflush(stderr);
+        return;
+        /*
+         * Alternatively, we could call our error-handler just like libpng
+         * does, which would effectively terminate the program.  Since this
+         * can only happen if png_ptr gets redirected somewhere odd or the
+         * main PNG struct gets wiped, we're probably toast anyway.  (If
+         * png_ptr itself is NULL, we would not have been called.)
+         */
+    }
+    /* this is just like in the non-progressive case */
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+       NULL, NULL, NULL);
+    mainprog_ptr->width = (ulg)width;
+    mainprog_ptr->height = (ulg)height;
+    /* since we know we've read all of the PNG file's "header" (i.e., up
+     * to IDAT), we can check for a background color here */
+    if (mainprog_ptr->need_bgcolor &&
+        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
+    {
+        png_color_16p pBackground;
+        /* it is not obvious from the libpng documentation, but this function
+         * takes a pointer to a pointer, and it always returns valid red,
+         * green and blue values, regardless of color_type: */
+        png_get_bKGD(png_ptr, info_ptr, &pBackground);
+        /* however, it always returns the raw bKGD data, regardless of any
+         * bit-depth transformations, so check depth and adjust if necessary */
+        if (bit_depth == 16) {
+            mainprog_ptr->bg_red   = pBackground->red   >> 8;
+            mainprog_ptr->bg_green = pBackground->green >> 8;
+            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
+        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
+            if (bit_depth == 1)
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = pBackground->gray? 255 : 0;
+            else if (bit_depth == 2)
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = (255/3) * pBackground->gray;
+            else /* bit_depth == 4 */
+                mainprog_ptr->bg_red = mainprog_ptr->bg_green =
+                  mainprog_ptr->bg_blue = (255/15) * pBackground->gray;
+        } else {
+            mainprog_ptr->bg_red   = (uch)pBackground->red;
+            mainprog_ptr->bg_green = (uch)pBackground->green;
+            mainprog_ptr->bg_blue  = (uch)pBackground->blue;
+        }
+    }
+    /* as before, let libpng expand palette images to RGB, low-bit-depth
+     * grayscale images to 8 bits, transparency chunks to full alpha channel;
+     * strip 16-bit-per-sample images to 8 bits per sample; and convert
+     * grayscale to RGB[A] */
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_expand(png_ptr);
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand(png_ptr);
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_expand(png_ptr);
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (bit_depth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+    if (color_type == PNG_COLOR_TYPE_GRAY ||
+        color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+    /* Unlike the basic viewer, which was designed to operate on local files,
+     * this program is intended to simulate a web browser--even though we
+     * actually read from a local file, too.  But because we are pretending
+     * that most of the images originate on the Internet, we follow the recom-
+     * mendation of the sRGB proposal and treat unlabelled images (no gAMA
+     * chunk) as existing in the sRGB color space.  That is, we assume that
+     * such images have a file gamma of 0.45455, which corresponds to a PC-like
+     * display system.  This change in assumptions will have no effect on a
+     * PC-like system, but on a Mac, SGI, NeXT or other system with a non-
+     * identity lookup table, it will darken unlabelled images, which effec-
+     * tively favors images from PC-like systems over those originating on
+     * the local platform.  Note that mainprog_ptr->display_exponent is the
+     * "gamma" value for the entire display system, i.e., the product of
+     * LUT_exponent and CRT_exponent. */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+    if (png_get_gAMA(png_ptr, info_ptr, &gamma))
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma);
+    else
+        png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455);
+#else
+    if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma))
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma);
+    else
+        png_set_gamma_fixed(png_ptr,
+            (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455);
+#endif
+    /* we'll let libpng expand interlaced images, too */
+    mainprog_ptr->passes = png_set_interlace_handling(png_ptr);
+    /* all transformations have been registered; now update info_ptr data and
+     * then get rowbytes and channels */
+    png_read_update_info(png_ptr, info_ptr);
+    mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr);
+    mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr);
+    /* Call the main program to allocate memory for the image buffer and
+     * initialize windows and whatnot.  (The old-style function-pointer
+     * invocation is used for compatibility with a few supposedly ANSI
+     * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */
+    (*mainprog_ptr->mainprog_init)();
+    /* and that takes care of initialization */
+    return;
+}
+static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row,
+                                  png_uint_32 row_num, int pass)
+{
+    mainprog_info  *mainprog_ptr;
+    /* first check whether the row differs from the previous pass; if not,
+     * nothing to combine or display */
+    if (!new_row)
+        return;
+    /* retrieve the pointer to our special-purpose struct so we can access
+     * the old rows and image-display callback function */
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+    /* save the pass number for optional use by the front end */
+    mainprog_ptr->pass = pass;
+    /* have libpng either combine the new row data with the existing row data
+     * from previous passes (if interlaced) or else just copy the new row
+     * into the main program's image buffer */
+    png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num],
+      new_row);
+    /* finally, call the display routine in the main program with the number
+     * of the row we just updated */
+    (*mainprog_ptr->mainprog_display_row)(row_num);
+    /* and we're ready for more */
+    return;
+}
+static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr)
+{
+    mainprog_info  *mainprog_ptr;
+    /* retrieve the pointer to our special-purpose struct */
+    mainprog_ptr = png_get_progressive_ptr(png_ptr);
+    /* let the main program know that it should flush any buffered image
+     * data to the display now and set a "done" flag or whatever, but note
+     * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do
+     * NOT call readpng2_cleanup() either here or in the finish_display()
+     * routine; wait until control returns to the main program via
+     * readpng2_decode_data() */
+    (*mainprog_ptr->mainprog_finish_display)();
+    /* all done */
+    return;
+}
+void readpng2_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    if (png_ptr && info_ptr)
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+    mainprog_ptr->png_ptr = NULL;
+    mainprog_ptr->info_ptr = NULL;
+}
+static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+    fprintf(stderr, "readpng2 libpng error: %s\n", msg);
+    fflush(stderr);
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "readpng2 severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.h
new file mode 100644
index 0000000..7a59263
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readpng2.h
@@ -0,0 +1,116 @@
+/*---------------------------------------------------------------------------
+   rpng2 - progressive-model PNG display program                 readpng2.h
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+enum rpng2_states {
+    kPreInit = 0,
+    kWindowInit,
+    kDone
+};
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+typedef struct _mainprog_info {
+    double display_exponent;
+    ulg width;
+    ulg height;
+    void *png_ptr;
+    void *info_ptr;
+    void (*mainprog_init)(void);
+    void (*mainprog_display_row)(ulg row_num);
+    void (*mainprog_finish_display)(void);
+    uch *image_data;
+    uch **row_pointers;
+    jmp_buf jmpbuf;
+    int passes;              /* not used */
+    int pass;
+    int rowbytes;
+    int channels;
+    int need_bgcolor;
+    int state;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+/* prototypes for public functions in readpng2.c */
+void readpng2_version_info(void);
+int readpng2_check_sig(uch *sig, int num);
+int readpng2_init(mainprog_info *mainprog_ptr);
+int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length);
+void readpng2_cleanup(mainprog_info *mainprog_ptr);
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readppm.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readppm.c
new file mode 100644
index 0000000..1ba2092
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/readppm.c
@@ -0,0 +1,179 @@
+/*---------------------------------------------------------------------------
+   rpng - simple PNG display program                              readppm.c
+  ---------------------------------------------------------------------------
+   This is a special-purpose replacement for readpng.c that allows binary
+   PPM files to be used in place of PNG images.
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#include <stdio.h>
+#include <stdlib.h>
+#include "readpng.h"    /* typedefs, common macros, public prototypes */
+ulg  width, height;
+int  bit_depth, color_type, channels;
+uch  *image_data = NULL;
+FILE *saved_infile;
+void readpng_version_info()
+{
+    fprintf(stderr, "   Compiled without libpng, zlib or PBMPLUS/NetPBM.\n");
+}
+/* return value = 0 for success, 1 for bad sig, 2 for bad IHDR, 4 for no mem */
+int readpng_init(FILE *infile, ulg *pWidth, ulg *pHeight)
+{
+    static uch ppmline[256];
+    int maxval;
+    saved_infile = infile;
+    fgets(ppmline, 256, infile);
+    if (ppmline[0] != 'P' || ppmline[1] != '6') {
+        fprintf(stderr, "ERROR:  not a PPM file\n");
+        return 1;
+    }
+    /* possible color types:  P5 = grayscale (0), P6 = RGB (2), P8 = RGBA (6) */
+    if (ppmline[1] == '6') {
+        color_type = 2;
+        channels = 3;
+    } else if (ppmline[1] == '8') {
+        color_type = 6;
+        channels = 4;
+    } else /* if (ppmline[1] == '5') */ {
+        color_type = 0;
+        channels = 1;
+    }
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%lu %lu", &width, &height);
+    do {
+        fgets(ppmline, 256, infile);
+    } while (ppmline[0] == '#');
+    sscanf(ppmline, "%d", &maxval);
+    if (maxval != 255) {
+        fprintf(stderr, "ERROR:  maxval = %d\n", maxval);
+        return 2;
+    }
+    bit_depth = 8;
+    *pWidth = width;
+    *pHeight = height;
+    return 0;
+}
+/* returns 0 if succeeds, 1 if fails due to no bKGD chunk, 2 if libpng error;
+ * scales values to 8-bit if necessary */
+int readpng_get_bgcolor(uch *red, uch *green, uch *blue)
+{
+    return 1;
+}
+/* display_exponent == LUT_exponent * CRT_exponent */
+uch *readpng_get_image(double display_exponent, int *pChannels, ulg *pRowbytes)
+{
+    ulg  rowbytes;
+    /* expand palette images to RGB, low-bit-depth grayscale images to 8 bits,
+     * transparency chunks to full alpha channel; strip 16-bit-per-sample
+     * images to 8 bits per sample; and convert grayscale to RGB[A] */
+    /* GRR WARNING:  grayscale needs to be expanded and channels reset! */
+    *pRowbytes = rowbytes = channels*width;
+    *pChannels = channels;
+    if ((image_data = (uch *)malloc(rowbytes*height)) == NULL) {
+        return NULL;
+    }
+    Trace((stderr, "readpng_get_image:  rowbytes = %ld, height = %ld\n", rowbytes, height));
+    /* now we can go ahead and just read the whole image */
+    fread(image_data, 1L, rowbytes*height, saved_infile);
+    return image_data;
+}
+void readpng_cleanup(int free_image_data)
+{
+    if (free_image_data && image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-win.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-win.c
new file mode 100644
index 0000000..1c22282
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-win.c
@@ -0,0 +1,728 @@
+/*---------------------------------------------------------------------------
+   rpng - simple PNG display program                             rpng-win.c
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for 32-bit Windows; it may compile under 16-bit Windows
+   with a little tweaking (or maybe not).
+   to do:
+    - handle quoted command-line args (especially filenames with spaces)
+    - have minimum window width:  oh well
+    - use %.1023s to simplify truncation of title-bar string?
+  ---------------------------------------------------------------------------
+   Changelog:
+    - 1.00:  initial public release
+    - 1.01:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.02:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#define PROGNAME  "rpng-win"
+#define LONGNAME  "Simple PNG Viewer for Windows"
+#define VERSION   "2.01 of 16 March 2008"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>      /* only for _getch() */
+#endif
+/* #define DEBUG  :  this enables the Trace() macros */
+#include "readpng.h"    /* typedefs, common macros, readpng prototypes */
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+/* local prototypes */
+static int        rpng_win_create_window(HINSTANCE hInst, int showmode);
+static int        rpng_win_display_image(void);
+static void       rpng_win_cleanup(void);
+LRESULT CALLBACK  rpng_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+static double display_exponent;
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+/* Windows-specific variables */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+static HWND global_hwnd;
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char *p, *q, **argv = args;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+    filename = (char *)NULL;
+#ifndef __CYGWIN__
+    /* First reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
+     * incantation. */
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+    /* Next set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+    /* Now parse the command line for options and the PNG filename. */
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+    if (!filename)
+        ++error;
+    /* print usage screen if any errors up to this point */
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg] file.png\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen.\n"
+#endif
+          "\n", PROGNAME, default_display_exponent);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+    }
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+    /* do the basic Windows initialization stuff, make the window and fill it
+     * with the background color */
+    if (rpng_win_create_window(hInst, showmode))
+        exit(2);
+    /* decode the image, all at once */
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+    readpng_cleanup(FALSE);
+    fclose(infile);
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+    /* display image (composite with background if requested) */
+    Trace((stderr, "calling rpng_win_display_image()\n"))
+    if (rpng_win_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_win_display_image()\n"))
+    /* wait for the user to tell us when to quit */
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+    /* OK, we're done:  clean up all image and Windows resources and go away */
+    rpng_win_cleanup();
+    return msg.wParam;
+}
+static int rpng_win_create_window(HINSTANCE hInst, int showmode)
+{
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+    wimage_rowbytes = ((3*image_width + 3L) >> 2) << 2;
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*image_height)))
+    {
+        return 4;   /* fail */
+    }
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = image_width;
+    bmih->biHeight = -((long)image_height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+/*---------------------------------------------------------------------------
+    Fill in background color (black by default); data are in BGR order.
+  ---------------------------------------------------------------------------*/
+    for (j = 0;  j < image_height;  ++j) {
+        dest = wimage_data + j*wimage_rowbytes;
+        for (i = image_width;  i > 0;  --i) {
+            *dest++ = bg_blue;
+            *dest++ = bg_green;
+            *dest++ = bg_red;
+        }
+    }
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+    memset(&wndclass, 0, sizeof(wndclass));
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng_win_wndproc;
+    wndclass.hInstance = hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+    RegisterClassEx(&wndclass);
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, image_width+extra_width,
+      image_height+extra_height, NULL, NULL, hInst, NULL);
+    ShowWindow(global_hwnd, showmode);
+    UpdateWindow(global_hwnd);
+    return 0;
+} /* end function rpng_win_create_window() */
+static int rpng_win_display_image()
+{
+    uch *src, *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow;
+    RECT rect;
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "(width = %ld, rowbytes = %ld, wimage_rowbytes = %d)\n",
+      image_width, image_rowbytes, wimage_rowbytes))
+/*---------------------------------------------------------------------------
+    Blast image data to buffer.  This whole routine takes place before the
+    message loop begins, so there's no real point in any pseudo-progressive
+    display...
+  ---------------------------------------------------------------------------*/
+    for (lastrow = row = 0;  row < image_height;  ++row) {
+        src = image_data + row*image_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        if (image_channels == 3) {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dest++ = b;
+                *dest++ = g;   /* note reverse order */
+                *dest++ = r;
+            }
+        } else /* if (image_channels == 4) */ {
+            for (i = image_width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (a == 255) {
+                    *dest++ = b;
+                    *dest++ = g;
+                    *dest++ = r;
+                } else if (a == 0) {
+                    *dest++ = bg_blue;
+                    *dest++ = bg_green;
+                    *dest++ = bg_red;
+                } else {
+                    /* this macro (copied from png.h) composites the
+                     * foreground and background values and puts the
+                     * result into the first argument; there are no
+                     * side effects with the first argument */
+                    alpha_composite(*dest++, b, a, bg_blue);
+                    alpha_composite(*dest++, g, a, bg_green);
+                    alpha_composite(*dest++, r, a, bg_red);
+                }
+            }
+        }
+        /* display after every 16 lines */
+        if (((row+1) & 0xf) == 0) {
+            rect.left = 0L;
+            rect.top = (LONG)lastrow;
+            rect.right = (LONG)image_width;      /* possibly off by one? */
+            rect.bottom = (LONG)lastrow + 16L;   /* possibly off by one? */
+            InvalidateRect(global_hwnd, &rect, FALSE);
+            UpdateWindow(global_hwnd);     /* similar to XFlush() */
+            lastrow = row + 1;
+        }
+    }
+    Trace((stderr, "calling final image-flush routine\n"))
+    if (lastrow < image_height) {
+        rect.left = 0L;
+        rect.top = (LONG)lastrow;
+        rect.right = (LONG)image_width;      /* possibly off by one? */
+        rect.bottom = (LONG)image_height;    /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);     /* similar to XFlush() */
+    }
+/*
+    last param determines whether or not background is wiped before paint
+    InvalidateRect(global_hwnd, NULL, TRUE);
+    UpdateWindow(global_hwnd);
+ */
+    return 0;
+}
+static void rpng_win_cleanup()
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+LRESULT CALLBACK rpng_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+                    /*                    dest                          */
+            rc = StretchDIBits(hdc, 0, 0, image_width, image_height,
+                    /*                    source                        */
+                                    0, 0, image_width, image_height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                    /*              iUsage: no clue                     */
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {      /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:     /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+        case WM_LBUTTONDOWN:   /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-x.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-x.c
new file mode 100644
index 0000000..fc8be88
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng-x.c
@@ -0,0 +1,904 @@
+/*---------------------------------------------------------------------------
+   rpng - simple PNG display program                               rpng-x.c
+   This program decodes and displays PNG images, with gamma correction and
+   optionally with a user-specified background color (in case the image has
+   transparency).  It is very nearly the most basic PNG viewer possible.
+   This version is for the X Window System (tested by author under Unix and
+   by Martin Zinser under OpenVMS; may work under OS/2 with some tweaking).
+   to do:
+    - 8-bit (colormapped) X support
+    - use %.1023s to simplify truncation of title-bar string?
+  ---------------------------------------------------------------------------
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed long/ulong mis-
+              match; switched to png_jmpbuf() macro
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added extra set of parentheses to png_jmpbuf() macro; fixed
+              command-line parsing bug
+    - 1.12:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
+    - 1.13:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.14:  added support for X resources (thanks to Gerhard Niklasch)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed improper display of usage screen on PNG error(s)
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#define PROGNAME  "rpng-x"
+#define LONGNAME  "Simple PNG Viewer for X"
+#define VERSION   "2.01 of 16 March 2008"
+#define RESNAME   "rpng"        /* our X resource application name */
+#define RESCLASS  "Rpng"        /* our X resource class name */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>
+/* #define DEBUG  :  this enables the Trace() macros */
+#include "readpng.h"   /* typedefs, common macros, readpng prototypes */
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+/* local prototypes */
+static int  rpng_x_create_window(void);
+static int  rpng_x_display_image(void);
+static void rpng_x_cleanup(void);
+static int  rpng_x_msb(ulg u32val);
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+static char *bgstr;
+static uch bg_red=0, bg_green=0, bg_blue=0;
+static double display_exponent;
+static ulg image_width, image_height, image_rowbytes;
+static int image_channels;
+static uch *image_data;
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+/*
+ulg numcolors=0, pixels[256];
+ush reds[256], greens[256], blues[256];
+ */
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p;
+    int rc, alen, flen;
+    int error = 0;
+    int have_bg = FALSE;
+    double LUT_exponent;               /* just the lookup table */
+    double CRT_exponent = 2.2;         /* just the monitor */
+    double default_display_exponent;   /* whole display system */
+    XEvent e;
+    KeySym k;
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+    /* First set the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+#if defined(NeXT)
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to get the
+     * "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        display_exponent = atof(p);
+    else
+        display_exponent = default_display_exponent;
+    /* Now parse the command line for options and the PNG filename. */
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                display_exponent = atof(*argv);
+                if (display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else
+                    have_bg = TRUE;
+            }
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+    if (!filename)
+        ++error;
+    /* print usage screen if any errors up to this point */
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+        readpng_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg] file.png\n"
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n"
+          "\n", PROGNAME, default_display_exponent);
+        exit(1);
+    }
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        if ((rc = readpng_init(infile, &image_width, &image_height)) != 0) {
+            switch (rc) {
+                case 1:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] is not a PNG file: incorrect signature\n",
+                      filename);
+                    break;
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng_cleanup(TRUE);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+    /* if the user didn't specify a background color on the command line,
+     * check for one in the PNG file--if not, the initialized values of 0
+     * (black) will be used */
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        bg_red   = (uch)r;
+        bg_green = (uch)g;
+        bg_blue  = (uch)b;
+    } else if (readpng_get_bgcolor(&bg_red, &bg_green, &bg_blue) > 1) {
+        readpng_cleanup(TRUE);
+        fprintf(stderr, PROGNAME
+          ":  libpng error while checking for background color\n");
+        exit(2);
+    }
+    /* do the basic X initialization stuff, make the window and fill it
+     * with the background color */
+    if (rpng_x_create_window())
+        exit(2);
+    /* decode the image, all at once */
+    Trace((stderr, "calling readpng_get_image()\n"))
+    image_data = readpng_get_image(display_exponent, &image_channels,
+      &image_rowbytes);
+    Trace((stderr, "done with readpng_get_image()\n"))
+    /* done with PNG file, so clean up to minimize memory usage (but do NOT
+     * nuke image_data!) */
+    readpng_cleanup(FALSE);
+    fclose(infile);
+    if (!image_data) {
+        fprintf(stderr, PROGNAME ":  unable to decode PNG image\n");
+        exit(3);
+    }
+    /* display image (composite with background if requested) */
+    Trace((stderr, "calling rpng_x_display_image()\n"))
+    if (rpng_x_display_image()) {
+        free(image_data);
+        exit(4);
+    }
+    Trace((stderr, "done with rpng_x_display_image()\n"))
+    /* wait for the user to tell us when to quit */
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+    do
+        XNextEvent(display, &e);
+    while (!(e.type == ButtonPress && e.xbutton.button == Button1) &&
+           !(e.type == KeyPress &&    /*  v--- or 1 for shifted keys */
+             ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape) ));
+    /* OK, we're done:  clean up all image and X resources and go away */
+    rpng_x_cleanup();
+    return 0;
+}
+static int rpng_x_create_window(void)
+{
+    uch *xdata;
+    int need_colormap = FALSE;
+    int screen, pad;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+#if 0
+/* GRR:  add 8-bit support */
+    if (/* depth != 8 && */ depth != 16 && depth != 24 && depth != 32) {
+        fprintf(stderr,
+          "screen depth %d not supported (only 16-, 24- or 32-bit TrueColor)\n",
+          depth);
+        return 2;
+    }
+    XMatchVisualInfo(display, screen, depth,
+      (depth == 8)? PseudoColor : TrueColor, &visual_info);
+    visual = visual_info.visual;
+#else
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+#endif
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng_x_msb(GMask);
+        BShift = 15 - rpng_x_msb(BMask);
+    } else if (depth > 16) {
+#define NO_24BIT_MASKS
+#ifdef NO_24BIT_MASKS
+        RShift = rpng_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng_x_msb(GMask) - 7;
+        BShift = rpng_x_msb(BMask) - 7;
+#else
+        RShift = 7 - rpng_x_msb(RMask);     /* these are right-shifts, too */
+        GShift = 7 - rpng_x_msb(GMask);
+        BShift = 7 - rpng_x_msb(BMask);
+#endif
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+    window = XCreateWindow(display, root, 0, 0, image_width, image_height, 0,
+      depth, InputOutput, visual, attrmask, &attr);
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+    /* OK if any hints allocation fails; XSetWMProperties() allows NULLs */
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)image_width;
+        size_hints->min_height = size_hints->max_height = (int)image_height;
+    }
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+    XMapWindow(display, window);
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        bg_pixel = ((ulg)bg_red   << RShift) |
+                   ((ulg)bg_green << GShift) |
+                   ((ulg)bg_blue  << BShift);
+    } else if (depth == 16) {
+        bg_pixel = ((((ulg)bg_red   << 8) >> RShift) & RMask) |
+                   ((((ulg)bg_green << 8) >> GShift) & GMask) |
+                   ((((ulg)bg_blue  << 8) >> BShift) & BMask);
+    } else /* depth == 8 */ {
+        /* GRR:  add 8-bit support */
+    }
+    XSetForeground(display, gc, bg_pixel);
+    XFillRectangle(display, window, gc, 0, 0, image_width, image_height);
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush.
+  ---------------------------------------------------------------------------*/
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+    XFlush(display);
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*image_width*image_height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*image_width*image_height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(image_width*image_height);
+        pad = 8;
+    }
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, image_width, image_height, pad, 0);
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (like Linux/x86, old VAXen, etc.)--this is not the most
+     * efficient approach (the giant if-test would be better), but in the
+     * interest of clarity, we take the easy way out... */
+    ximage->byte_order = MSBFirst;
+    return 0;
+} /* end function rpng_x_create_window() */
+static int rpng_x_display_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+/*  int bpp = ximage->bits_per_pixel;  */
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      image_channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %ld, ximage_rowbytes = %d)\n",
+      image_width, image_rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG:  this assumes bpp == 32, but may be 24: */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+#endif
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+    } else if (depth == 16) {
+        ush red, green, blue;
+        for (lastrow = row = 0;  row < image_height;  ++row) {
+            src = image_data + row*image_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (image_channels == 3) {
+                for (i = image_width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (image_channels == 4) */ {
+                for (i = image_width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, image_width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+    } else /* depth == 8 */ {
+        /* GRR:  add 8-bit support */
+    }
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < image_height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, image_width, image_height-lastrow);
+        XFlush(display);
+    }
+    return 0;
+}
+static void rpng_x_cleanup(void)
+{
+    if (image_data) {
+        free(image_data);
+        image_data = NULL;
+    }
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+    if (have_gc)
+        XFreeGC(display, gc);
+    if (have_window)
+        XDestroyWindow(display, window);
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+static int rpng_x_msb(ulg u32val)
+{
+    int i;
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-win.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-win.c
new file mode 100644
index 0000000..2303b58
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-win.c
@@ -0,0 +1,1253 @@
+/*---------------------------------------------------------------------------
+   rpng2 - progressive-model PNG display program                rpng2-win.c
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for 32-bit Windows; it may compile under 16-bit Windows with a little
+   tweaking (or maybe not).  Thanks to Adam Costello and Pieter S. van der
+   Meulen for the "diamond" and "radial waves" patterns, respectively.
+   to do (someday, maybe):
+    - handle quoted command-line args (especially filenames with spaces)
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+    - have minimum window width:  oh well
+  ---------------------------------------------------------------------------
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  fixed cut-and-paste error in usage screen (oops...)
+    - 1.03:  modified to allow abbreviated options
+    - 1.04:  removed bogus extra argument from usage fprintf() [Glenn R-P?];
+              fixed command-line parsing bug
+    - 1.10:  enabled "message window"/console (thanks to David Geldreich)
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  made minor tweak to usage screen to fit within 25-line console
+    - 1.22:  added AMD64/EM64T support (__x86_64__)
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases
+    - 2.03:  removed runtime MMX-enabling/disabling and obsolete -mmx* options
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#define PROGNAME  "rpng2-win"
+#define LONGNAME  "Progressive PNG Viewer for Windows"
+#define VERSION   "2.02 of 16 March 2008"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>    /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>      /* only for PvdM background code */
+#include <windows.h>
+#ifdef __CYGWIN__
+/* getch replacement. Turns out, we don't really need this,
+ * but leave it here if we ever enable any of the uses of
+ * _getch in the main code
+ */
+#include <unistd.h>
+#include <termio.h>
+#include <sys/ioctl.h>
+int repl_getch( void )
+{
+  char ch;
+  int fd = fileno(stdin);
+  struct termio old_tty, new_tty;
+  ioctl(fd, TCGETA, &old_tty);
+  new_tty = old_tty;
+  new_tty.c_lflag &= ~(ICANON | ECHO | ISIG);
+  ioctl(fd, TCSETA, &new_tty);
+  fread(&ch, 1, sizeof(ch), stdin);
+  ioctl(fd, TCSETA, &old_tty);
+  return ch;
+}
+#define _getch repl_getch
+#else
+#include <conio.h>     /* only for _getch() */
+#endif
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+/* #define DEBUG */     /* this enables the Trace() macros */
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+/* local prototypes */
+static void       rpng2_win_init(void);
+static int        rpng2_win_create_window(void);
+static int        rpng2_win_load_bg_image(void);
+static void       rpng2_win_display_row(ulg row);
+static void       rpng2_win_finish_display(void);
+static void       rpng2_win_cleanup(void);
+LRESULT CALLBACK  rpng2_win_wndproc(HWND, UINT, WPARAM, LPARAM);
+static char titlebar[1024];
+static char *progname = PROGNAME;
+static char *appname = LONGNAME;
+static char *filename;
+static FILE *infile;
+static mainprog_info rpng2_info;
+static uch inbuf[INBUFSIZE];
+static int incount;
+static int pat = 6;         /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200}     /* 15:  ice blue */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+/* Windows-specific global variables (could go in struct, but messy...) */
+static ulg wimage_rowbytes;
+static uch *dib;
+static uch *wimage_data;
+static BITMAPINFOHEADER *bmih;
+static HWND global_hwnd;
+static HINSTANCE global_hInst;
+static int global_showmode;
+int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, PSTR cmd, int showmode)
+{
+    char *args[1024];                 /* arbitrary limit, but should suffice */
+    char **argv = args;
+    char *p, *q, *bgstr = NULL;
+    int argc = 0;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+    double LUT_exponent;              /* just the lookup table */
+    double CRT_exponent = 2.2;        /* just the monitor */
+    double default_display_exponent;  /* whole display system */
+    MSG msg;
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+    global_hInst = hInst;
+    global_showmode = showmode;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+#ifndef __CYGWIN__
+    /* Next reenable console output, which normally goes to the bit bucket
+     * for windowed apps.  Closing the console window will terminate the
+     * app.  Thanks to David.Geldreich@realviz.com for supplying the magical
+     * incantation. */
+    AllocConsole();
+    freopen("CONOUT$", "a", stderr);
+    freopen("CONOUT$", "a", stdout);
+#endif
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities.  And
+     * yes, these ifdefs are completely wasted in a Windows program... */
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+    /* Windows really hates command lines, so we have to set up our own argv.
+     * Note that we do NOT bother with quoted arguments here, so don't use
+     * filenames with spaces in 'em! */
+    argv[argc++] = PROGNAME;
+    p = cmd;
+    for (;;) {
+        if (*p == ' ')
+            while (*++p == ' ')
+                ;
+        /* now p points at the first non-space after some spaces */
+        if (*p == '\0')
+            break;    /* nothing after the spaces:  done */
+        argv[argc++] = q = p;
+        while (*q && *q != ' ')
+            ++q;
+        /* now q points at a space or the end of the string */
+        if (*q == '\0')
+            break;    /* last argv already terminated; quit */
+        *q = '\0';    /* change space to terminator */
+        p = q + 1;
+    }
+    argv[argc] = NULL;   /* terminate the argv array itself */
+    /* Now parse the command line for options and the PNG filename. */
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv) - 1;
+                if (pat < 0 || pat >= num_bgpat)
+                    ++error;
+                else {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+    if (!filename)
+        ++error;
+    /* print usage screen if any errors up to this point */
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-gamma exp] [-bgcolor bg | -bgpat pat] [-timing]\n"
+          "        %*s file.png\n\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat option\n"
+          "    pat \tdesired background pattern number (1-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor option\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "\nPress Q, Esc or mouse button 1 after image is displayed to quit.\n"
+#ifndef __CYGWIN__
+          "Press Q or Esc to quit this usage screen. ",
+#else
+          ,
+#endif
+          PROGNAME,
+#if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__)) && \
+    !(defined(__CYGWIN__) || defined(__MINGW32__))
+          (int)strlen(PROGNAME), " ",
+#endif
+          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat);
+        fflush(stderr);
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(1);
+    }
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        }
+        if (error)
+            fclose(infile);
+    }
+    if (error) {
+#ifndef __CYGWIN__
+        int ch;
+#endif
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+#ifndef __CYGWIN__
+        do
+            ch = _getch();
+        while (ch != 'q' && ch != 'Q' && ch != 0x1B);
+#endif
+        exit(2);
+    } else {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, appname);
+#ifndef __CYGWIN__
+        fprintf(stderr,
+          "\n   [console window:  closing this window will terminate %s]\n\n",
+          PROGNAME);
+#endif
+        fflush(stderr);
+    }
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+    /* set some final rpng2_info variables before entering main data loop */
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_win_init;
+    rpng2_info.mainprog_display_row = rpng2_win_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_win_finish_display;
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call Sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+        if (timing)
+            Sleep(1000L);
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+    /* clean up PNG stuff and report any decoding errors */
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+    /* wait for the user to tell us when to quit */
+    while (GetMessage(&msg, NULL, 0, 0)) {
+        TranslateMessage(&msg);
+        DispatchMessage(&msg);
+    }
+    /* we're done:  clean up all image and Windows resources and go away */
+    Trace((stderr, "about to call rpng2_win_cleanup()\n"))
+    rpng2_win_cleanup();
+    return msg.wParam;
+}
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+static void rpng2_win_init()
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+    Trace((stderr, "beginning rpng2_win_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+/*---------------------------------------------------------------------------
+    Do the basic Windows initialization stuff, make the window, and fill it
+    with the user-specified, file-specified or default background color.
+  ---------------------------------------------------------------------------*/
+    if (rpng2_win_create_window()) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+    rpng2_info.state = kWindowInit;
+}
+static int rpng2_win_create_window()
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *dest;
+    int extra_width, extra_height;
+    ulg i, j;
+    WNDCLASSEX wndclass;
+    RECT rect;
+/*---------------------------------------------------------------------------
+    Allocate memory for the display-specific version of the image (round up
+    to multiple of 4 for Windows DIB).
+  ---------------------------------------------------------------------------*/
+    wimage_rowbytes = ((3*rpng2_info.width + 3L) >> 2) << 2;
+    if (!(dib = (uch *)malloc(sizeof(BITMAPINFOHEADER) +
+                              wimage_rowbytes*rpng2_info.height)))
+    {
+        return 4;   /* fail */
+    }
+/*---------------------------------------------------------------------------
+    Initialize the DIB.  Negative height means to use top-down BMP ordering
+    (must be uncompressed, but that's what we want).  Bit count of 1, 4 or 8
+    implies a colormap of RGBX quads, but 24-bit BMPs just use B,G,R values
+    directly => wimage_data begins immediately after BMP header.
+  ---------------------------------------------------------------------------*/
+    memset(dib, 0, sizeof(BITMAPINFOHEADER));
+    bmih = (BITMAPINFOHEADER *)dib;
+    bmih->biSize = sizeof(BITMAPINFOHEADER);
+    bmih->biWidth = rpng2_info.width;
+    bmih->biHeight = -((long)rpng2_info.height);
+    bmih->biPlanes = 1;
+    bmih->biBitCount = 24;
+    bmih->biCompression = 0;
+    wimage_data = dib + sizeof(BITMAPINFOHEADER);
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black), but
+    defer loading faked "background image" until window is displayed (may be
+    slow to compute).  Data are in BGR order.
+  ---------------------------------------------------------------------------*/
+    if (bg_image) {   /* just fill with black for now */
+        memset(wimage_data, 0, wimage_rowbytes*rpng2_info.height);
+    } else {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+/*---------------------------------------------------------------------------
+    Set the window parameters.
+  ---------------------------------------------------------------------------*/
+    memset(&wndclass, 0, sizeof(wndclass));
+    wndclass.cbSize = sizeof(wndclass);
+    wndclass.style = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc = rpng2_win_wndproc;
+    wndclass.hInstance = global_hInst;
+    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
+    wndclass.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
+    wndclass.lpszMenuName = NULL;
+    wndclass.lpszClassName = progname;
+    wndclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
+    RegisterClassEx(&wndclass);
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+    extra_width  = 2*(GetSystemMetrics(SM_CXBORDER) +
+                      GetSystemMetrics(SM_CXDLGFRAME));
+    extra_height = 2*(GetSystemMetrics(SM_CYBORDER) +
+                      GetSystemMetrics(SM_CYDLGFRAME)) +
+                      GetSystemMetrics(SM_CYCAPTION);
+    global_hwnd = CreateWindow(progname, titlebar, WS_OVERLAPPEDWINDOW,
+      CW_USEDEFAULT, CW_USEDEFAULT, rpng2_info.width+extra_width,
+      rpng2_info.height+extra_height, NULL, NULL, global_hInst, NULL);
+    ShowWindow(global_hwnd, global_showmode);
+    UpdateWindow(global_hwnd);
+/*---------------------------------------------------------------------------
+    Now compute the background image and display it.  If it fails (memory
+    allocation), revert to a plain background color.
+  ---------------------------------------------------------------------------*/
+    if (bg_image) {
+        static const char *msg = "Computing background image...";
+        int x, y, len = strlen(msg);
+        HDC hdc = GetDC(global_hwnd);
+        TEXTMETRIC tm;
+        GetTextMetrics(hdc, &tm);
+        x = (rpng2_info.width - len*tm.tmAveCharWidth)/2;
+        y = (rpng2_info.height - tm.tmHeight)/2;
+        SetBkMode(hdc, TRANSPARENT);
+        SetTextColor(hdc, GetSysColor(COLOR_HIGHLIGHTTEXT));
+        /* this can still begin out of bounds even if x is positive (???): */
+        TextOut(hdc, ((x < 0)? 0 : x), ((y < 0)? 0 : y), msg, len);
+        ReleaseDC(global_hwnd, hdc);
+        rpng2_win_load_bg_image();   /* resets bg_image if fails */
+    }
+    if (!bg_image) {
+        for (j = 0;  j < rpng2_info.height;  ++j) {
+            dest = wimage_data + j*wimage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            }
+        }
+    }
+    rect.left = 0L;
+    rect.top = 0L;
+    rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+    rect.bottom = (LONG)rpng2_info.height;     /* possibly off by one? */
+    InvalidateRect(global_hwnd, &rect, FALSE);
+    UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+    return 0;
+} /* end function rpng2_win_create_window() */
+static int rpng2_win_load_bg_image()
+{
+    uch *src, *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max = (bgscale-1);
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            even_odd_vert = (row / bgscale) & 1;
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (i / bgscale) & 1;
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {         /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                     /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;        /* not inverted or */
+                        *dest++ = g2;        /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;    /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 1) {
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = row % bgscale;
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = i % bgscale;
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+        hh = rpng2_info.height / 2;
+        hw = rpng2_info.width / 2;
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = row - hh;
+            dest = bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = i - hw;
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode;
+    calling function will handle invalidation and UpdateWindow() call.
+  ---------------------------------------------------------------------------*/
+    for (row = 0;  row < rpng2_info.height;  ++row) {
+        src = bg_data + row*bg_rowbytes;
+        dest = wimage_data + row*wimage_rowbytes;
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r1 = *src++;
+            g1 = *src++;
+            b1 = *src++;
+            *dest++ = b1;
+            *dest++ = g1;   /* note reverse order */
+            *dest++ = r1;
+        }
+    }
+    return 0;
+} /* end function rpng2_win_load_bg_image() */
+static void rpng2_win_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL, *dest;
+    uch r, g, b, a;
+    ulg i;
+    static int rows=0;
+    static ulg firstrow;
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call InvalidateRect() for
+    every row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+    Trace((stderr, "beginning rpng2_win_display_row()\n"))
+    if (rows == 0)
+        firstrow = row;   /* first row not yet displayed */
+    ++rows;   /* count of rows received but not yet displayed */
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and the lack of an outer
+    loop (over rows), this routine is identical to rpng_win_display_image()
+    in the non-progressive version of the program.
+  ---------------------------------------------------------------------------*/
+    src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+    if (bg_image)
+        src2 = bg_data + row*bg_rowbytes;
+    dest = wimage_data + row*wimage_rowbytes;
+    if (rpng2_info.channels == 3) {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            *dest++ = b;
+            *dest++ = g;   /* note reverse order */
+            *dest++ = r;
+        }
+    } else /* if (rpng2_info.channels == 4) */ {
+        for (i = rpng2_info.width;  i > 0;  --i) {
+            r = *src++;
+            g = *src++;
+            b = *src++;
+            a = *src++;
+            if (bg_image) {
+                bg_red   = *src2++;
+                bg_green = *src2++;
+                bg_blue  = *src2++;
+            }
+            if (a == 255) {
+                *dest++ = b;
+                *dest++ = g;
+                *dest++ = r;
+            } else if (a == 0) {
+                *dest++ = bg_blue;
+                *dest++ = bg_green;
+                *dest++ = bg_red;
+            } else {
+                /* this macro (copied from png.h) composites the
+                 * foreground and background values and puts the
+                 * result into the first argument; there are no
+                 * side effects with the first argument */
+                alpha_composite(*dest++, b, a, bg_blue);
+                alpha_composite(*dest++, g, a, bg_green);
+                alpha_composite(*dest++, r, a, bg_red);
+            }
+        }
+    }
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on last row.  (Region may include
+    previously displayed lines due to interlacing--i.e., not contiguous.)
+  ---------------------------------------------------------------------------*/
+    if ((rows & 0xf) == 0 || row == rpng2_info.height-1) {
+        RECT rect;
+        rect.left = 0L;
+        rect.top = (LONG)firstrow;
+        rect.right = (LONG)rpng2_info.width;       /* possibly off by one? */
+        rect.bottom = (LONG)row + 1L;              /* possibly off by one? */
+        InvalidateRect(global_hwnd, &rect, FALSE);
+        UpdateWindow(global_hwnd);                 /* similar to XFlush() */
+        rows = 0;
+    }
+} /* end function rpng2_win_display_row() */
+static void rpng2_win_finish_display()
+{
+    Trace((stderr, "beginning rpng2_win_finish_display()\n"))
+    /* last row has already been displayed by rpng2_win_display_row(), so
+     * we have nothing to do here except set a flag and let the user know
+     * that the image is done */
+    rpng2_info.state = kDone;
+    printf(
+#ifndef __CYGWIN__
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n"
+#else
+      "Done.  Press mouse button 1 (within image window) to quit.\n"
+#endif
+    );
+    fflush(stdout);
+}
+static void rpng2_win_cleanup()
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+    if (dib) {
+        free(dib);
+        dib = NULL;
+    }
+}
+LRESULT CALLBACK rpng2_win_wndproc(HWND hwnd, UINT iMsg, WPARAM wP, LPARAM lP)
+{
+    HDC         hdc;
+    PAINTSTRUCT ps;
+    int rc;
+    switch (iMsg) {
+        case WM_CREATE:
+            /* one-time processing here, if any */
+            return 0;
+        case WM_PAINT:
+            hdc = BeginPaint(hwnd, &ps);
+            rc = StretchDIBits(hdc, 0, 0, rpng2_info.width, rpng2_info.height,
+                                    0, 0, rpng2_info.width, rpng2_info.height,
+                                    wimage_data, (BITMAPINFO *)bmih,
+                                    0, SRCCOPY);
+            EndPaint(hwnd, &ps);
+            return 0;
+        /* wait for the user to tell us when to quit */
+        case WM_CHAR:
+            switch (wP) {       /* only need one, so ignore repeat count */
+                case 'q':
+                case 'Q':
+                case 0x1B:      /* Esc key */
+                    PostQuitMessage(0);
+            }
+            return 0;
+        case WM_LBUTTONDOWN:    /* another way of quitting */
+        case WM_DESTROY:
+            PostQuitMessage(0);
+            return 0;
+    }
+    return DefWindowProc(hwnd, iMsg, wP, lP);
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-x.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-x.c
new file mode 100644
index 0000000..6c687db
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/rpng2-x.c
@@ -0,0 +1,2107 @@
+/*---------------------------------------------------------------------------
+   rpng2 - progressive-model PNG display program                  rpng2-x.c
+   This program decodes and displays PNG files progressively, as if it were
+   a web browser (though the front end is only set up to read from files).
+   It supports gamma correction, user-specified background colors, and user-
+   specified background patterns (for transparent images).  This version is
+   for the X Window System (tested by the author under Unix and by Martin
+   Zinser under OpenVMS; may work under OS/2 with a little tweaking).
+   Thanks to Adam Costello and Pieter S. van der Meulen for the "diamond"
+   and "radial waves" patterns, respectively.
+   to do (someday, maybe):
+    - fix expose/redraw code:  don't draw entire row if only part exposed
+    - 8-bit (colormapped) X support
+    - finish resizable checkerboard-gradient (sizes 4-128?)
+    - use %.1023s to simplify truncation of title-bar string?
+  ---------------------------------------------------------------------------
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options; fixed char/uchar mismatch
+    - 1.10:  added support for non-default visuals; fixed X pixel-conversion
+    - 1.11:  added -usleep option for demos; fixed command-line parsing bug
+    - 1.12:  added -pause option for demos and testing
+    - 1.20:  added runtime MMX-enabling/disabling and new -mmx* options
+    - 1.21:  fixed some small X memory leaks (thanks to Fran�ois Petitjean)
+    - 1.22:  fixed XFreeGC() crash bug (thanks to Patrick Welche)
+    - 1.23:  added -bgpat 0 mode (std white/gray checkerboard, 8x8 squares)
+    - 1.30:  added -loop option for -bgpat (ifdef FEATURE_LOOP); fixed bpp =
+              24; added support for X resources (thanks to Gerhard Niklasch)
+    - 1.31:  added code to skip unused chunks (thanks to Glenn Randers-Pehrson)
+    - 1.32:  added AMD64/EM64T support (__x86_64__); added basic expose/redraw
+              handling
+    - 2.00:  dual-licensed (added GNU GPL)
+    - 2.01:  fixed 64-bit typo in readpng2.c; fixed -pause usage description
+    - 2.02:  fixed improper display of usage screen on PNG error(s); fixed
+              unexpected-EOF and file-read-error cases; fixed Trace() cut-and-
+              paste bugs
+    - 2.03:  deleted runtime MMX-enabling/disabling and obsolete -mmx* options
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2008 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#define PROGNAME  "rpng2-x"
+#define LONGNAME  "Progressive PNG Viewer for X"
+#define VERSION   "2.03 of 25 February 2010"
+#define RESNAME   "rpng2"       /* our X resource application name */
+#define RESCLASS  "Rpng"       /* our X resource class name */
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <setjmp.h>       /* for jmpbuf declaration in readpng2.h */
+#include <time.h>
+#include <math.h>         /* only for PvdM background code */
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
+#include <X11/Xos.h>
+#include <X11/keysym.h>   /* defines XK_* macros */
+#ifdef VMS
+#  include <unistd.h>
+#endif
+/* all for PvdM background code: */
+#ifndef PI
+#  define PI             3.141592653589793238
+#endif
+#define PI_2             (PI*0.5)
+#define INV_PI_360       (360.0 / PI)
+#define MAX(a,b)         (a>b?a:b)
+#define MIN(a,b)         (a<b?a:b)
+#define CLIP(a,min,max)  MAX(min,MIN((a),max))
+#define ABS(a)           ((a)<0?-(a):(a))
+#define CLIP8P(c)        MAX(0,(MIN((c),255)))   /* 8-bit pos. integer (uch) */
+#define ROUNDF(f)        ((int)(f + 0.5))
+#define QUIT(e,k) ((e.type == ButtonPress && e.xbutton.button == Button1) ||  \
+                  (e.type == KeyPress &&   /*  v--- or 1 for shifted keys */  \
+                  ((k = XLookupKeysym(&e.xkey, 0)) == XK_q || k == XK_Escape)))
+#define NO_24BIT_MASKS /* undef case not fully written--only for redisplay() */
+#define rgb1_max   bg_freq
+#define rgb1_min   bg_gray
+#define rgb2_max   bg_bsat
+#define rgb2_min   bg_brot
+/* #define DEBUG */     /* this enables the Trace() macros */
+#include "readpng2.h"   /* typedefs, common macros, readpng2 prototypes */
+/* could just include png.h, but this macro is the only thing we need
+ * (name and typedefs changed to local versions); note that side effects
+ * only happen with alpha (which could easily be avoided with
+ * "ush acopy = (alpha);") */
+#define alpha_composite(composite, fg, alpha, bg) {               \
+    ush temp = ((ush)(fg)*(ush)(alpha) +                          \
+                (ush)(bg)*(ush)(255 - (ush)(alpha)) + (ush)128);  \
+    (composite) = (uch)((temp + (temp >> 8)) >> 8);               \
+}
+#define INBUFSIZE 4096   /* with pseudo-timing on (1 sec delay/block), this
+                          *  block size corresponds roughly to a download
+                          *  speed 10% faster than theoretical 33.6K maximum
+                          *  (assuming 8 data bits, 1 stop bit and no other
+                          *  overhead) */
+/* local prototypes */
+static void rpng2_x_init (void);
+static int  rpng2_x_create_window (void);
+static int  rpng2_x_load_bg_image (void);
+static void rpng2_x_display_row (ulg row);
+static void rpng2_x_finish_display (void);
+static void rpng2_x_redisplay_image (ulg startcol, ulg startrow,
+                                     ulg width, ulg height);
+#ifdef FEATURE_LOOP
+static void rpng2_x_reload_bg_image (void);
+static int  is_number (char *p);
+#endif
+static void rpng2_x_cleanup (void);
+static int  rpng2_x_msb (ulg u32val);
+static char titlebar[1024], *window_name = titlebar;
+static char *appname = LONGNAME;
+static char *icon_name = PROGNAME;
+static char *res_name = RESNAME;
+static char *res_class = RESCLASS;
+static char *filename;
+static FILE *infile;
+static mainprog_info rpng2_info;
+static uch inbuf[INBUFSIZE];
+static int incount;
+static int pat = 6;        /* must be less than num_bgpat */
+static int bg_image = 0;
+static int bgscale, bgscale_default = 16;
+static ulg bg_rowbytes;
+static uch *bg_data;
+int pause_after_pass = FALSE;
+int demo_timing = FALSE;
+ulg usleep_duration = 0L;
+static struct rgb_color {
+    uch r, g, b;
+} rgb[] = {
+    {  0,   0,   0},    /*  0:  black */
+    {255, 255, 255},    /*  1:  white */
+    {173, 132,  57},    /*  2:  tan */
+    { 64, 132,   0},    /*  3:  medium green */
+    {189, 117,   1},    /*  4:  gold */
+    {253, 249,   1},    /*  5:  yellow */
+    {  0,   0, 255},    /*  6:  blue */
+    {  0,   0, 120},    /*  7:  medium blue */
+    {255,   0, 255},    /*  8:  magenta */
+    { 64,   0,  64},    /*  9:  dark magenta */
+    {255,   0,   0},    /* 10:  red */
+    { 64,   0,   0},    /* 11:  dark red */
+    {255, 127,   0},    /* 12:  orange */
+    {192,  96,   0},    /* 13:  darker orange */
+    { 24,  60,   0},    /* 14:  dark green-yellow */
+    { 85, 125, 200},    /* 15:  ice blue */
+    {192, 192, 192}     /* 16:  Netscape/Mosaic gray */
+};
+/* not used for now, but should be for error-checking:
+static int num_rgb = sizeof(rgb) / sizeof(struct rgb_color);
+ */
+/*
+    This whole struct is a fairly cheesy way to keep the number of
+    command-line options to a minimum.  The radial-waves background
+    type is a particularly poor fit to the integer elements of the
+    struct...but a few macros and a little fixed-point math will do
+    wonders for ya.
+    type bits:
+       F E D C B A 9 8 7 6 5 4 3 2 1 0
+                             | | | | |
+                             | | +-+-+-- 0 = sharp-edged checkerboard
+                             | |         1 = soft diamonds
+                             | |         2 = radial waves
+                             | |       3-7 = undefined
+                             | +-- gradient #2 inverted?
+                             +-- alternating columns inverted?
+ */
+static struct background_pattern {
+    ush type;
+    int rgb1_max, rgb1_min;     /* or bg_freq, bg_gray */
+    int rgb2_max, rgb2_min;     /* or bg_bsat, bg_brot (both scaled by 10)*/
+} bg[] = {
+    {0,     1,1, 16,16},        /* checkered:  white vs. light gray (basic) */
+    {0+8,   2,0,  1,15},        /* checkered:  tan/black vs. white/ice blue */
+    {0+24,  2,0,  1,0},         /* checkered:  tan/black vs. white/black */
+    {0+8,   4,5,  0,2},         /* checkered:  gold/yellow vs. black/tan */
+    {0+8,   4,5,  0,6},         /* checkered:  gold/yellow vs. black/blue */
+    {0,     7,0,  8,9},         /* checkered:  deep blue/black vs. magenta */
+    {0+8,  13,0,  5,14},        /* checkered:  orange/black vs. yellow */
+    {0+8,  12,0, 10,11},        /* checkered:  orange/black vs. red */
+    {1,     7,0,  8,0},         /* diamonds:  deep blue/black vs. magenta */
+    {1,    12,0, 11,0},         /* diamonds:  orange vs. dark red */
+    {1,    10,0,  7,0},         /* diamonds:  red vs. medium blue */
+    {1,     4,0,  5,0},         /* diamonds:  gold vs. yellow */
+    {1,     3,0,  0,0},         /* diamonds:  medium green vs. black */
+    {2,    16, 100,  20,   0},  /* radial:  ~hard radial color-beams */
+    {2,    18, 100,  10,   2},  /* radial:  soft, curved radial color-beams */
+    {2,    16, 256, 100, 250},  /* radial:  very tight spiral */
+    {2, 10000, 256,  11,   0}   /* radial:  dipole-moire' (almost fractal) */
+};
+static int num_bgpat = sizeof(bg) / sizeof(struct background_pattern);
+/* X-specific variables */
+static char *displayname;
+static XImage *ximage;
+static Display *display;
+static int depth;
+static Visual *visual;
+static XVisualInfo *visual_list;
+static int RShift, GShift, BShift;
+static ulg RMask, GMask, BMask;
+static Window window;
+static GC gc;
+static Colormap colormap;
+static int have_nondefault_visual = FALSE;
+static int have_colormap = FALSE;
+static int have_window = FALSE;
+static int have_gc = FALSE;
+int main(int argc, char **argv)
+{
+#ifdef sgi
+    char tmpline[80];
+#endif
+    char *p, *bgstr = NULL;
+    int rc, alen, flen;
+    int error = 0;
+    int timing = FALSE;
+    int have_bg = FALSE;
+#ifdef FEATURE_LOOP
+    int loop = FALSE;
+    long loop_interval = -1;            /* seconds (100,000 max) */
+#endif
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    XEvent e;
+    KeySym k;
+    /* First initialize a few things, just to be sure--memset takes care of
+     * default background color (black), booleans (FALSE), pointers (NULL),
+     * etc. */
+    displayname = (char *)NULL;
+    filename = (char *)NULL;
+    memset(&rpng2_info, 0, sizeof(mainprog_info));
+    /* Set the default value for our display-system exponent, i.e., the
+     * product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  This is not an
+     * exhaustive list of LUT values (e.g., OpenStep has a lot of weird
+     * ones), but it should cover 99% of the current possibilities. */
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    infile = fopen("/etc/config/system.glGammaVal", "r");
+    if (infile) {
+        double sgi_gamma;
+        fgets(tmpline, 80, infile);
+        fclose(infile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+    if ((p = getenv("SCREEN_GAMMA")) != NULL)
+        rpng2_info.display_exponent = atof(p);
+    else
+        rpng2_info.display_exponent = default_display_exponent;
+    /* Now parse the command line for options and the PNG filename. */
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-display", 2)) {
+            if (!*++argv)
+                ++error;
+            else
+                displayname = *argv;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                rpng2_info.display_exponent = atof(*argv);
+                if (rpng2_info.display_exponent <= 0.0)
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    have_bg = TRUE;
+                    bg_image = FALSE;
+                }
+            }
+        } else if (!strncmp(*argv, "-bgpat", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                pat = atoi(*argv);
+                if (pat >= 0 && pat < num_bgpat) {
+                    bg_image = TRUE;
+                    have_bg = FALSE;
+                } else
+                    ++error;
+            }
+        } else if (!strncmp(*argv, "-usleep", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                usleep_duration = (ulg)atol(*argv);
+                demo_timing = TRUE;
+            }
+        } else if (!strncmp(*argv, "-pause", 2)) {
+            pause_after_pass = TRUE;
+        } else if (!strncmp(*argv, "-timing", 2)) {
+            timing = TRUE;
+#ifdef FEATURE_LOOP
+        } else if (!strncmp(*argv, "-loop", 2)) {
+            loop = TRUE;
+            if (!argv[1] || !is_number(argv[1]))
+                loop_interval = 2;
+            else {
+                ++argv;
+                loop_interval = atol(*argv);
+                if (loop_interval < 0)
+                    loop_interval = 2;
+                else if (loop_interval > 100000)   /* bit more than one day */
+                    loop_interval = 100000;
+            }
+#endif
+        } else {
+            if (**argv != '-') {
+                filename = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+    if (!filename)
+        ++error;
+    /* print usage screen if any errors up to this point */
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n\n", PROGNAME, VERSION, appname);
+        readpng2_version_info();
+        fprintf(stderr, "\n"
+          "Usage:  %s [-display xdpy] [-gamma exp] [-bgcolor bg | -bgpat pat]\n"
+#ifdef FEATURE_LOOP
+          "        %*s [-usleep dur | -timing] [-pause] [-loop [sec]] file.png\n\n"
+#else
+          "        %*s [-usleep dur | -timing] [-pause] file.png\n\n"
+#endif
+          "    xdpy\tname of the target X display (e.g., ``hostname:0'')\n"
+          "    exp \ttransfer-function exponent (``gamma'') of the display\n"
+          "\t\t  system in floating-point format (e.g., ``%.1f''); equal\n"
+          "\t\t  to the product of the lookup-table exponent (varies)\n"
+          "\t\t  and the CRT exponent (usually 2.2); must be positive\n"
+          "    bg  \tdesired background color in 7-character hex RGB format\n"
+          "\t\t  (e.g., ``#ff7700'' for orange:  same as HTML colors);\n"
+          "\t\t  used with transparent images; overrides -bgpat\n"
+          "    pat \tdesired background pattern number (0-%d); used with\n"
+          "\t\t  transparent images; overrides -bgcolor\n"
+#ifdef FEATURE_LOOP
+          "    -loop\tloops through background images after initial display\n"
+          "\t\t  is complete (depends on -bgpat)\n"
+          "    sec \tseconds to display each background image (default = 2)\n"
+#endif
+          "    dur \tduration in microseconds to wait after displaying each\n"
+          "\t\t  row (for demo purposes)\n"
+          "    -timing\tenables delay for every block read, to simulate modem\n"
+          "\t\t  download of image (~36 Kbps)\n"
+          "    -pause\tpauses after displaying each pass until mouse clicked\n"
+          "\nPress Q, Esc or mouse button 1 (within image window, after image\n"
+          "is displayed) to quit.\n"
+          "\n", PROGNAME,
+          (int)strlen(PROGNAME), " ", default_display_exponent, num_bgpat-1);
+        exit(1);
+    }
+    if (!(infile = fopen(filename, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open PNG file [%s]\n", filename);
+        ++error;
+    } else {
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+        if (incount < 8 || !readpng2_check_sig(inbuf, 8)) {
+            fprintf(stderr, PROGNAME
+              ":  [%s] is not a PNG file: incorrect signature\n",
+              filename);
+            ++error;
+        } else if ((rc = readpng2_init(&rpng2_info)) != 0) {
+            switch (rc) {
+                case 2:
+                    fprintf(stderr, PROGNAME
+                      ":  [%s] has bad IHDR (libpng longjmp)\n", filename);
+                    break;
+                case 4:
+                    fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                    break;
+                default:
+                    fprintf(stderr, PROGNAME
+                      ":  unknown readpng2_init() error\n");
+                    break;
+            }
+            ++error;
+        } else {
+            Trace((stderr, "about to call XOpenDisplay()\n"))
+            display = XOpenDisplay(displayname);
+            if (!display) {
+                readpng2_cleanup(&rpng2_info);
+                fprintf(stderr, PROGNAME ":  can't open X display [%s]\n",
+                  displayname? displayname : "default");
+                ++error;
+            }
+        }
+        if (error)
+            fclose(infile);
+    }
+    if (error) {
+        fprintf(stderr, PROGNAME ":  aborting.\n");
+        exit(2);
+    }
+    /* set the title-bar string, but make sure buffer doesn't overflow */
+    alen = strlen(appname);
+    flen = strlen(filename);
+    if (alen + flen + 3 > 1023)
+        sprintf(titlebar, "%s:  ...%s", appname, filename+(alen+flen+6-1023));
+    else
+        sprintf(titlebar, "%s:  %s", appname, filename);
+    /* set some final rpng2_info variables before entering main data loop */
+    if (have_bg) {
+        unsigned r, g, b;   /* this approach quiets compiler warnings */
+        sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+        rpng2_info.bg_red   = (uch)r;
+        rpng2_info.bg_green = (uch)g;
+        rpng2_info.bg_blue  = (uch)b;
+    } else
+        rpng2_info.need_bgcolor = TRUE;
+    rpng2_info.state = kPreInit;
+    rpng2_info.mainprog_init = rpng2_x_init;
+    rpng2_info.mainprog_display_row = rpng2_x_display_row;
+    rpng2_info.mainprog_finish_display = rpng2_x_finish_display;
+    /* OK, this is the fun part:  call readpng2_decode_data() at the start of
+     * the loop to deal with our first buffer of data (read in above to verify
+     * that the file is a PNG image), then loop through the file and continue
+     * calling the same routine to handle each chunk of data.  It in turn
+     * passes the data to libpng, which will invoke one or more of our call-
+     * backs as decoded data become available.  We optionally call sleep() for
+     * one second per iteration to simulate downloading the image via an analog
+     * modem. */
+    for (;;) {
+        Trace((stderr, "about to call readpng2_decode_data()\n"))
+        if (readpng2_decode_data(&rpng2_info, inbuf, incount))
+            ++error;
+        Trace((stderr, "done with readpng2_decode_data()\n"))
+        if (error || incount != INBUFSIZE || rpng2_info.state == kDone) {
+            if (rpng2_info.state == kDone) {
+                Trace((stderr, "done decoding PNG image\n"))
+            } else if (ferror(infile)) {
+                fprintf(stderr, PROGNAME
+                  ":  error while reading PNG image file\n");
+                exit(3);
+            } else if (feof(infile)) {
+                fprintf(stderr, PROGNAME ":  end of file reached "
+                  "(unexpectedly) while reading PNG image file\n");
+                exit(3);
+            } else /* if (error) */ {
+                /* will print error message below */
+            }
+            break;
+        }
+        if (timing)
+            sleep(1);
+        incount = fread(inbuf, 1, INBUFSIZE, infile);
+    }
+    /* clean up PNG stuff and report any decoding errors */
+    fclose(infile);
+    Trace((stderr, "about to call readpng2_cleanup()\n"))
+    readpng2_cleanup(&rpng2_info);
+    if (error) {
+        fprintf(stderr, PROGNAME ":  libpng error while decoding PNG image\n");
+        exit(3);
+    }
+#ifdef FEATURE_LOOP
+    if (loop && bg_image) {
+        Trace((stderr, "entering -loop loop (FEATURE_LOOP)\n"))
+        for (;;) {
+            int i, use_sleep;
+            struct timeval now, then;
+            /* get current time and add loop_interval to get target time */
+            if (gettimeofday(&then, NULL) == 0) {
+                then.tv_sec += loop_interval;
+                use_sleep = FALSE;
+            } else
+                use_sleep = TRUE;
+            /* do quick check for a quit event but don't wait for it */
+            /* GRR BUG:  should also check for Expose events and redraw... */
+            if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask, &e))
+                if (QUIT(e,k))
+                    break;
+            /* generate next background image */
+            if (++pat >= num_bgpat)
+                pat = 0;
+            rpng2_x_reload_bg_image();
+            /* wait for timeout, using whatever means are available */
+            if (use_sleep || gettimeofday(&now, NULL) != 0) {
+                for (i = loop_interval;  i > 0;  --i) {
+                    sleep(1);
+                    /* GRR BUG:  also need to check for Expose (and redraw!) */
+                    if (XCheckMaskEvent(display, KeyPressMask | ButtonPressMask,
+                        &e) && QUIT(e,k))
+                        break;
+                }
+            } else {
+                /* Y2038 BUG! */
+                if (now.tv_sec < then.tv_sec ||
+                    (now.tv_sec == then.tv_sec && now.tv_usec < then.tv_usec))
+                {
+                    int quit = FALSE;
+                    long seconds_to_go = then.tv_sec - now.tv_sec;
+                    long usleep_usec;
+                    /* basically chew up most of remaining loop-interval with
+                     *  calls to sleep(1) interleaved with checks for quit
+                     *  events, but also recalc time-to-go periodically; when
+                     *  done, clean up any remaining time with usleep() call
+                     *  (could also use SIGALRM, but signals are a pain...) */
+                    while (seconds_to_go-- > 1) {
+                        int seconds_done = 0;
+                        for (i = seconds_to_go;  i > 0 && !quit;  --i) {
+                            sleep(1);
+                            /* GRR BUG:  need to check for Expose and redraw */
+                            if (XCheckMaskEvent(display, KeyPressMask |
+                                ButtonPressMask, &e) && QUIT(e,k))
+                                quit = TRUE;
+                            if (++seconds_done > 1000)
+                                break;   /* time to redo seconds_to_go meas. */
+                        }
+                        if (quit)
+                            break;
+                        /* OK, more than 1000 seconds since last check:
+                         *  correct the time-to-go measurement for drift */
+                        if (gettimeofday(&now, NULL) == 0) {
+                            if (now.tv_sec >= then.tv_sec)
+                                break;
+                            seconds_to_go = then.tv_sec - now.tv_sec;
+                        } else
+                            ++seconds_to_go;  /* restore what we subtracted */
+                    }
+                    if (quit)
+                        break;   /* breaks outer do-loop, skips redisplay */
+                    /* since difference between "now" and "then" is already
+                     *  eaten up to within a couple of seconds, don't need to
+                     *  worry about overflow--but might have overshot (neg.) */
+                    if (gettimeofday(&now, NULL) == 0) {
+                        usleep_usec = 1000000L*(then.tv_sec - now.tv_sec) +
+                          then.tv_usec - now.tv_usec;
+                        if (usleep_usec > 0)
+                            usleep((ulg)usleep_usec);
+                    }
+                }
+            }
+            /* composite image against new background and display (note that
+             *  we do not take into account the time spent doing this...) */
+            rpng2_x_redisplay_image (0, 0, rpng2_info.width, rpng2_info.height);
+        }
+    } else /* FALL THROUGH and do the normal thing */
+#endif /* FEATURE_LOOP */
+    /* wait for the user to tell us when to quit */
+    if (rpng2_info.state >= kWindowInit) {
+        Trace((stderr, "entering final wait-for-quit-event loop\n"))
+        do {
+            XNextEvent(display, &e);
+            if (e.type == Expose) {
+                XExposeEvent *ex = (XExposeEvent *)&e;
+                rpng2_x_redisplay_image (ex->x, ex->y, ex->width, ex->height);
+            }
+        } while (!QUIT(e,k));
+    } else {
+        fprintf(stderr, PROGNAME ":  init callback never called:  probable "
+          "libpng error while decoding PNG metadata\n");
+        exit(4);
+    }
+    /* we're done:  clean up all image and X resources and go away */
+    Trace((stderr, "about to call rpng2_x_cleanup()\n"))
+    rpng2_x_cleanup();
+    return 0;
+}
+/* this function is called by readpng2_info_callback() in readpng2.c, which
+ * in turn is called by libpng after all of the pre-IDAT chunks have been
+ * read and processed--i.e., we now have enough info to finish initializing */
+static void rpng2_x_init(void)
+{
+    ulg i;
+    ulg rowbytes = rpng2_info.rowbytes;
+    Trace((stderr, "beginning rpng2_x_init()\n"))
+    Trace((stderr, "  rowbytes = %d\n", rpng2_info.rowbytes))
+    Trace((stderr, "  width  = %ld\n", rpng2_info.width))
+    Trace((stderr, "  height = %ld\n", rpng2_info.height))
+    rpng2_info.image_data = (uch *)malloc(rowbytes * rpng2_info.height);
+    if (!rpng2_info.image_data) {
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+    rpng2_info.row_pointers = (uch **)malloc(rpng2_info.height * sizeof(uch *));
+    if (!rpng2_info.row_pointers) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+        readpng2_cleanup(&rpng2_info);
+        return;
+    }
+    for (i = 0;  i < rpng2_info.height;  ++i)
+        rpng2_info.row_pointers[i] = rpng2_info.image_data + i*rowbytes;
+    /* do the basic X initialization stuff, make the window, and fill it with
+     * the user-specified, file-specified or default background color or
+     * pattern */
+    if (rpng2_x_create_window()) {
+        /* GRR TEMPORARY HACK:  this is fundamentally no different from cases
+         * above; libpng should call our error handler to longjmp() back to us
+         * when png_ptr goes away.  If we/it segfault instead, seems like a
+         * libpng bug... */
+        /* we're here via libpng callback, so if window fails, clean and bail */
+        readpng2_cleanup(&rpng2_info);
+        rpng2_x_cleanup();
+        exit(2);
+    }
+    rpng2_info.state = kWindowInit;
+}
+static int rpng2_x_create_window(void)
+{
+    ulg bg_red   = rpng2_info.bg_red;
+    ulg bg_green = rpng2_info.bg_green;
+    ulg bg_blue  = rpng2_info.bg_blue;
+    ulg bg_pixel = 0L;
+    ulg attrmask;
+    int need_colormap = FALSE;
+    int screen, pad;
+    uch *xdata;
+    Window root;
+    XEvent e;
+    XGCValues gcvalues;
+    XSetWindowAttributes attr;
+    XTextProperty windowName, *pWindowName = &windowName;
+    XTextProperty iconName, *pIconName = &iconName;
+    XVisualInfo visual_info;
+    XSizeHints *size_hints;
+    XWMHints *wm_hints;
+    XClassHint *class_hints;
+    Trace((stderr, "beginning rpng2_x_create_window()\n"))
+    screen = DefaultScreen(display);
+    depth = DisplayPlanes(display, screen);
+    root = RootWindow(display, screen);
+#ifdef DEBUG
+    XSynchronize(display, True);
+#endif
+    if (depth != 16 && depth != 24 && depth != 32) {
+        int visuals_matched = 0;
+        Trace((stderr, "default depth is %d:  checking other visuals\n",
+          depth))
+        /* 24-bit first */
+        visual_info.screen = screen;
+        visual_info.depth = 24;
+        visual_list = XGetVisualInfo(display,
+          VisualScreenMask | VisualDepthMask, &visual_info, &visuals_matched);
+        if (visuals_matched == 0) {
+/* GRR:  add 15-, 16- and 32-bit TrueColor visuals (also DirectColor?) */
+            fprintf(stderr, "default screen depth %d not supported, and no"
+              " 24-bit visuals found\n", depth);
+            return 2;
+        }
+        Trace((stderr, "XGetVisualInfo() returned %d 24-bit visuals\n",
+          visuals_matched))
+        visual = visual_list[0].visual;
+        depth = visual_list[0].depth;
+/*
+        colormap_size = visual_list[0].colormap_size;
+        visual_class = visual->class;
+        visualID = XVisualIDFromVisual(visual);
+ */
+        have_nondefault_visual = TRUE;
+        need_colormap = TRUE;
+    } else {
+        XMatchVisualInfo(display, screen, depth, TrueColor, &visual_info);
+        visual = visual_info.visual;
+    }
+    RMask = visual->red_mask;
+    GMask = visual->green_mask;
+    BMask = visual->blue_mask;
+/* GRR:  add/check 8-bit support */
+    if (depth == 8 || need_colormap) {
+        colormap = XCreateColormap(display, root, visual, AllocNone);
+        if (!colormap) {
+            fprintf(stderr, "XCreateColormap() failed\n");
+            return 2;
+        }
+        have_colormap = TRUE;
+        if (depth == 8)
+            bg_image = FALSE;   /* gradient just wastes palette entries */
+    }
+    if (depth == 15 || depth == 16) {
+        RShift = 15 - rpng2_x_msb(RMask);    /* these are right-shifts */
+        GShift = 15 - rpng2_x_msb(GMask);
+        BShift = 15 - rpng2_x_msb(BMask);
+    } else if (depth > 16) {
+        RShift = rpng2_x_msb(RMask) - 7;     /* these are left-shifts */
+        GShift = rpng2_x_msb(GMask) - 7;
+        BShift = rpng2_x_msb(BMask) - 7;
+    }
+    if (depth >= 15 && (RShift < 0 || GShift < 0 || BShift < 0)) {
+        fprintf(stderr, "rpng2 internal logic error:  negative X shift(s)!\n");
+        return 2;
+    }
+/*---------------------------------------------------------------------------
+    Finally, create the window.
+  ---------------------------------------------------------------------------*/
+    attr.backing_store = Always;
+    attr.event_mask = ExposureMask | KeyPressMask | ButtonPressMask;
+    attrmask = CWBackingStore | CWEventMask;
+    if (have_nondefault_visual) {
+        attr.colormap = colormap;
+        attr.background_pixel = 0;
+        attr.border_pixel = 1;
+        attrmask |= CWColormap | CWBackPixel | CWBorderPixel;
+    }
+    window = XCreateWindow(display, root, 0, 0, rpng2_info.width,
+      rpng2_info.height, 0, depth, InputOutput, visual, attrmask, &attr);
+    if (window == None) {
+        fprintf(stderr, "XCreateWindow() failed\n");
+        return 2;
+    } else
+        have_window = TRUE;
+    if (depth == 8)
+        XSetWindowColormap(display, window, colormap);
+    if (!XStringListToTextProperty(&window_name, 1, pWindowName))
+        pWindowName = NULL;
+    if (!XStringListToTextProperty(&icon_name, 1, pIconName))
+        pIconName = NULL;
+    /* OK if either hints allocation fails; XSetWMProperties() allows NULLs */
+    if ((size_hints = XAllocSizeHints()) != NULL) {
+        /* window will not be resizable */
+        size_hints->flags = PMinSize | PMaxSize;
+        size_hints->min_width = size_hints->max_width = (int)rpng2_info.width;
+        size_hints->min_height = size_hints->max_height =
+          (int)rpng2_info.height;
+    }
+    if ((wm_hints = XAllocWMHints()) != NULL) {
+        wm_hints->initial_state = NormalState;
+        wm_hints->input = True;
+     /* wm_hints->icon_pixmap = icon_pixmap; */
+        wm_hints->flags = StateHint | InputHint  /* | IconPixmapHint */ ;
+    }
+    if ((class_hints = XAllocClassHint()) != NULL) {
+        class_hints->res_name = res_name;
+        class_hints->res_class = res_class;
+    }
+    XSetWMProperties(display, window, pWindowName, pIconName, NULL, 0,
+      size_hints, wm_hints, class_hints);
+    /* various properties and hints no longer needed; free memory */
+    if (pWindowName)
+       XFree(pWindowName->value);
+    if (pIconName)
+       XFree(pIconName->value);
+    if (size_hints)
+        XFree(size_hints);
+    if (wm_hints)
+       XFree(wm_hints);
+    if (class_hints)
+       XFree(class_hints);
+    XMapWindow(display, window);
+    gc = XCreateGC(display, window, 0, &gcvalues);
+    have_gc = TRUE;
+/*---------------------------------------------------------------------------
+    Allocate memory for the X- and display-specific version of the image.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        xdata = (uch *)malloc(4*rpng2_info.width*rpng2_info.height);
+        pad = 32;
+    } else if (depth == 16) {
+        xdata = (uch *)malloc(2*rpng2_info.width*rpng2_info.height);
+        pad = 16;
+    } else /* depth == 8 */ {
+        xdata = (uch *)malloc(rpng2_info.width*rpng2_info.height);
+        pad = 8;
+    }
+    if (!xdata) {
+        fprintf(stderr, PROGNAME ":  unable to allocate image memory\n");
+        return 4;
+    }
+    ximage = XCreateImage(display, visual, depth, ZPixmap, 0,
+      (char *)xdata, rpng2_info.width, rpng2_info.height, pad, 0);
+    if (!ximage) {
+        fprintf(stderr, PROGNAME ":  XCreateImage() failed\n");
+        free(xdata);
+        return 3;
+    }
+    /* to avoid testing the byte order every pixel (or doubling the size of
+     * the drawing routine with a giant if-test), we arbitrarily set the byte
+     * order to MSBFirst and let Xlib worry about inverting things on little-
+     * endian machines (e.g., Linux/x86, old VAXen, etc.)--this is not the
+     * most efficient approach (the giant if-test would be better), but in
+     * the interest of clarity, we'll take the easy way out... */
+    ximage->byte_order = MSBFirst;
+/*---------------------------------------------------------------------------
+    Fill window with the specified background color (default is black) or
+    faked "background image" (but latter is disabled if 8-bit; gradients
+    just waste palette entries).
+  ---------------------------------------------------------------------------*/
+    if (bg_image)
+        rpng2_x_load_bg_image();    /* resets bg_image if fails */
+    if (!bg_image) {
+        if (depth == 24 || depth == 32) {
+            bg_pixel = (bg_red   << RShift) |
+                       (bg_green << GShift) |
+                       (bg_blue  << BShift);
+        } else if (depth == 16) {
+            bg_pixel = (((bg_red   << 8) >> RShift) & RMask) |
+                       (((bg_green << 8) >> GShift) & GMask) |
+                       (((bg_blue  << 8) >> BShift) & BMask);
+        } else /* depth == 8 */ {
+            /* GRR:  add 8-bit support */
+        }
+        XSetForeground(display, gc, bg_pixel);
+        XFillRectangle(display, window, gc, 0, 0, rpng2_info.width,
+          rpng2_info.height);
+    }
+/*---------------------------------------------------------------------------
+    Wait for first Expose event to do any drawing, then flush and return.
+  ---------------------------------------------------------------------------*/
+    do
+        XNextEvent(display, &e);
+    while (e.type != Expose || e.xexpose.count);
+    XFlush(display);
+    return 0;
+} /* end function rpng2_x_create_window() */
+static int rpng2_x_load_bg_image(void)
+{
+    uch *src;
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, row;
+    ulg pixel;
+/*---------------------------------------------------------------------------
+    Allocate buffer for fake background image to be used with transparent
+    images; if this fails, revert to plain background color.
+  ---------------------------------------------------------------------------*/
+    bg_rowbytes = 3 * rpng2_info.width;
+    bg_data = (uch *)malloc(bg_rowbytes * rpng2_info.height);
+    if (!bg_data) {
+        fprintf(stderr, PROGNAME
+          ":  unable to allocate memory for background image\n");
+        bg_image = 0;
+        return 1;
+    }
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 1) {
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+        fprintf(stderr, "%s:  computing radial background...",
+          PROGNAME);
+        fflush(stderr);
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+        fprintf(stderr, "done.\n");
+        fflush(stderr);
+    }
+/*---------------------------------------------------------------------------
+    Blast background image to display buffer before beginning PNG decode.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (bpp == 32) {    /* slightly optimized version */
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+    } else if (depth == 16) {
+        ush red, green, blue;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            src = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);  ++src;
+                green = ((ush)(*src) << 8);  ++src;
+                blue  = ((ush)(*src) << 8);  ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+    } else /* depth == 8 */ {
+        /* GRR:  add 8-bit support */
+    }
+    XPutImage(display, window, gc, ximage, 0, 0, 0, 0, rpng2_info.width,
+      rpng2_info.height);
+    return 0;
+} /* end function rpng2_x_load_bg_image() */
+static void rpng2_x_display_row(ulg row)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    ulg i, pixel;
+    static int rows=0, prevpass=(-1);
+    static ulg firstrow;
+/*---------------------------------------------------------------------------
+    rows and firstrow simply track how many rows (and which ones) have not
+    yet been displayed; alternatively, we could call XPutImage() for every
+    row and not bother with the records-keeping.
+  ---------------------------------------------------------------------------*/
+    Trace((stderr, "beginning rpng2_x_display_row()\n"))
+    if (rpng2_info.pass != prevpass) {
+        if (pause_after_pass && rpng2_info.pass > 0) {
+            XEvent e;
+            KeySym k;
+            fprintf(stderr,
+              "%s:  end of pass %d of 7; click in image window to continue\n",
+              PROGNAME, prevpass + 1);
+            do
+                XNextEvent(display, &e);
+            while (!QUIT(e,k));
+        }
+        fprintf(stderr, "%s:  pass %d of 7\r", PROGNAME, rpng2_info.pass + 1);
+        fflush(stderr);
+        prevpass = rpng2_info.pass;
+    }
+    if (rows == 0)
+        firstrow = row;   /* first row that is not yet displayed */
+    ++rows;   /* count of rows received but not yet displayed */
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct, the lack of an outer loop
+    (over rows) and moving the XPutImage() call outside the "if (depth)"
+    tests, this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+        src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = *src++;
+                green = *src++;
+                blue  = *src++;
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = r;
+                    green = g;
+                    blue  = b;
+                } else if (a == 0) {
+                    red   = bg_red;
+                    green = bg_green;
+                    blue  = bg_blue;
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result into the
+                     * first argument */
+                    alpha_composite(red,   r, a, bg_red);
+                    alpha_composite(green, g, a, bg_green);
+                    alpha_composite(blue,  b, a, bg_blue);
+                }
+                pixel = (red   << RShift) |
+                        (green << GShift) |
+                        (blue  << BShift);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                if (bpp == 32) {
+                    *dest++ = (char)((pixel >> 24) & 0xff);
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                } else {
+                    /* GRR BUG?  this assumes bpp == 24 & bits are packed low */
+                    /*           (probably need to use RShift, RMask, etc.) */
+                    *dest++ = (char)((pixel >> 16) & 0xff);
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+        }
+    } else if (depth == 16) {
+        ush red, green, blue;
+        src = rpng2_info.row_pointers[row];
+        if (bg_image)
+            src2 = bg_data + row*bg_rowbytes;
+        dest = ximage->data + row*ximage_rowbytes;
+        if (rpng2_info.channels == 3) {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                red   = ((ush)(*src) << 8);
+                ++src;
+                green = ((ush)(*src) << 8);
+                ++src;
+                blue  = ((ush)(*src) << 8);
+                ++src;
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        } else /* if (rpng2_info.channels == 4) */ {
+            for (i = rpng2_info.width;  i > 0;  --i) {
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                a = *src++;
+                if (bg_image) {
+                    bg_red   = *src2++;
+                    bg_green = *src2++;
+                    bg_blue  = *src2++;
+                }
+                if (a == 255) {
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                } else if (a == 0) {
+                    red   = ((ush)bg_red   << 8);
+                    green = ((ush)bg_green << 8);
+                    blue  = ((ush)bg_blue  << 8);
+                } else {
+                    /* this macro (from png.h) composites the foreground
+                     * and background values and puts the result back into
+                     * the first argument (== fg byte here:  safe) */
+                    alpha_composite(r, r, a, bg_red);
+                    alpha_composite(g, g, a, bg_green);
+                    alpha_composite(b, b, a, bg_blue);
+                    red   = ((ush)r << 8);
+                    green = ((ush)g << 8);
+                    blue  = ((ush)b << 8);
+                }
+                pixel = ((red   >> RShift) & RMask) |
+                        ((green >> GShift) & GMask) |
+                        ((blue  >> BShift) & BMask);
+                /* recall that we set ximage->byte_order = MSBFirst above */
+                *dest++ = (char)((pixel >>  8) & 0xff);
+                *dest++ = (char)( pixel        & 0xff);
+            }
+        }
+    } else /* depth == 8 */ {
+        /* GRR:  add 8-bit support */
+    }
+/*---------------------------------------------------------------------------
+    Display after every 16 rows or when on one of last two rows.  (Region
+    may include previously displayed lines due to interlacing--i.e., not
+    contiguous.  Also, second-to-last row is final one in interlaced images
+    with odd number of rows.)  For demos, flush (and delay) after every 16th
+    row so "sparse" passes don't go twice as fast.
+  ---------------------------------------------------------------------------*/
+    if (demo_timing && (row - firstrow >= 16 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+        usleep(usleep_duration);
+    } else
+    if (!demo_timing && ((rows & 0xf) == 0 || row >= rpng2_info.height-2)) {
+        XPutImage(display, window, gc, ximage, 0, (int)firstrow, 0,
+          (int)firstrow, rpng2_info.width, row - firstrow + 1);
+        XFlush(display);
+        rows = 0;
+    }
+}
+static void rpng2_x_finish_display(void)
+{
+    Trace((stderr, "beginning rpng2_x_finish_display()\n"))
+    /* last row has already been displayed by rpng2_x_display_row(), so we
+     * have nothing to do here except set a flag and let the user know that
+     * the image is done */
+    rpng2_info.state = kDone;
+    printf(
+      "Done.  Press Q, Esc or mouse button 1 (within image window) to quit.\n");
+    fflush(stdout);
+}
+static void rpng2_x_redisplay_image(ulg startcol, ulg startrow,
+                                    ulg width, ulg height)
+{
+    uch bg_red   = rpng2_info.bg_red;
+    uch bg_green = rpng2_info.bg_green;
+    uch bg_blue  = rpng2_info.bg_blue;
+    uch *src, *src2=NULL;
+    char *dest;
+    uch r, g, b, a;
+    ulg i, row, lastrow = 0;
+    ulg pixel;
+    int ximage_rowbytes = ximage->bytes_per_line;
+    Trace((stderr, "beginning display loop (image_channels == %d)\n",
+      rpng2_info.channels))
+    Trace((stderr, "   (width = %ld, rowbytes = %d, ximage_rowbytes = %d)\n",
+      rpng2_info.width, rpng2_info.rowbytes, ximage_rowbytes))
+    Trace((stderr, "   (bpp = %d)\n", ximage->bits_per_pixel))
+    Trace((stderr, "   (byte_order = %s)\n", ximage->byte_order == MSBFirst?
+      "MSBFirst" : (ximage->byte_order == LSBFirst? "LSBFirst" : "unknown")))
+/*---------------------------------------------------------------------------
+    Aside from the use of the rpng2_info struct and of src2 (for background
+    image), this routine is identical to rpng_x_display_image() in the non-
+    progressive version of the program--for the simple reason that redisplay
+    of the image against a new background happens after the image is fully
+    decoded and therefore is, by definition, non-progressive.
+  ---------------------------------------------------------------------------*/
+    if (depth == 24 || depth == 32) {
+        ulg red, green, blue;
+        int bpp = ximage->bits_per_pixel;
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.image_data + row*rpng2_info.rowbytes;
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = *src++;
+                    green = *src++;
+                    blue  = *src++;
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = r;
+                        green = g;
+                        blue  = b;
+                    } else if (a == 0) {
+                        red   = bg_red;
+                        green = bg_green;
+                        blue  = bg_blue;
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result into the
+                         * first argument */
+                        alpha_composite(red,   r, a, bg_red);
+                        alpha_composite(green, g, a, bg_green);
+                        alpha_composite(blue,  b, a, bg_blue);
+                    }
+#ifdef NO_24BIT_MASKS
+                    pixel = (red   << RShift) |
+                            (green << GShift) |
+                            (blue  << BShift);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift, RMask, etc.) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#else
+                    red   = (RShift < 0)? red   << (-RShift) : red   >> RShift;
+                    green = (GShift < 0)? green << (-GShift) : green >> GShift;
+                    blue  = (BShift < 0)? blue  << (-BShift) : blue  >> BShift;
+                    pixel = (red & RMask) | (green & GMask) | (blue & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    if (bpp == 32) {
+                        *dest++ = (char)((pixel >> 24) & 0xff);
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    } else {
+                        /* GRR BUG */
+                        /* this assumes bpp == 24 & bits are packed low */
+                        /* (probably need to use RShift/RMask/etc. here, too) */
+                        *dest++ = (char)((pixel >> 16) & 0xff);
+                        *dest++ = (char)((pixel >>  8) & 0xff);
+                        *dest++ = (char)( pixel        & 0xff);
+                    }
+#endif
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+    } else if (depth == 16) {
+        ush red, green, blue;
+        for (lastrow = row = startrow;  row < startrow+height;  ++row) {
+            src = rpng2_info.row_pointers[row];
+            if (bg_image)
+                src2 = bg_data + row*bg_rowbytes;
+            dest = ximage->data + row*ximage_rowbytes;
+            if (rpng2_info.channels == 3) {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    red   = ((ush)(*src) << 8);
+                    ++src;
+                    green = ((ush)(*src) << 8);
+                    ++src;
+                    blue  = ((ush)(*src) << 8);
+                    ++src;
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            } else /* if (rpng2_info.channels == 4) */ {
+                for (i = rpng2_info.width;  i > 0;  --i) {
+                    r = *src++;
+                    g = *src++;
+                    b = *src++;
+                    a = *src++;
+                    if (bg_image) {
+                        bg_red   = *src2++;
+                        bg_green = *src2++;
+                        bg_blue  = *src2++;
+                    }
+                    if (a == 255) {
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    } else if (a == 0) {
+                        red   = ((ush)bg_red   << 8);
+                        green = ((ush)bg_green << 8);
+                        blue  = ((ush)bg_blue  << 8);
+                    } else {
+                        /* this macro (from png.h) composites the foreground
+                         * and background values and puts the result back into
+                         * the first argument (== fg byte here:  safe) */
+                        alpha_composite(r, r, a, bg_red);
+                        alpha_composite(g, g, a, bg_green);
+                        alpha_composite(b, b, a, bg_blue);
+                        red   = ((ush)r << 8);
+                        green = ((ush)g << 8);
+                        blue  = ((ush)b << 8);
+                    }
+                    pixel = ((red   >> RShift) & RMask) |
+                            ((green >> GShift) & GMask) |
+                            ((blue  >> BShift) & BMask);
+                    /* recall that we set ximage->byte_order = MSBFirst above */
+                    *dest++ = (char)((pixel >>  8) & 0xff);
+                    *dest++ = (char)( pixel        & 0xff);
+                }
+            }
+            /* display after every 16 lines */
+            if (((row+1) & 0xf) == 0) {
+                XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+                  (int)lastrow, rpng2_info.width, 16);
+                XFlush(display);
+                lastrow = row + 1;
+            }
+        }
+    } else /* depth == 8 */ {
+        /* GRR:  add 8-bit support */
+    }
+    Trace((stderr, "calling final XPutImage()\n"))
+    if (lastrow < startrow+height) {
+        XPutImage(display, window, gc, ximage, 0, (int)lastrow, 0,
+          (int)lastrow, rpng2_info.width, rpng2_info.height-lastrow);
+        XFlush(display);
+    }
+} /* end function rpng2_x_redisplay_image() */
+#ifdef FEATURE_LOOP
+static void rpng2_x_reload_bg_image(void)
+{
+    char *dest;
+    uch r1, r2, g1, g2, b1, b2;
+    uch r1_inv, r2_inv, g1_inv, g2_inv, b1_inv, b2_inv;
+    int k, hmax, max;
+    int xidx, yidx, yidx_max;
+    int even_odd_vert, even_odd_horiz, even_odd;
+    int invert_gradient2 = (bg[pat].type & 0x08);
+    int invert_column;
+    ulg i, row;
+    bgscale = (pat == 0)? 8 : bgscale_default;
+    yidx_max = bgscale - 1;
+/*---------------------------------------------------------------------------
+    Vertical gradients (ramps) in NxN squares, alternating direction and
+    colors (N == bgscale).
+  ---------------------------------------------------------------------------*/
+    if ((bg[pat].type & 0x07) == 0) {
+        uch r1_min  = rgb[bg[pat].rgb1_min].r;
+        uch g1_min  = rgb[bg[pat].rgb1_min].g;
+        uch b1_min  = rgb[bg[pat].rgb1_min].b;
+        uch r2_min  = rgb[bg[pat].rgb2_min].r;
+        uch g2_min  = rgb[bg[pat].rgb2_min].g;
+        uch b2_min  = rgb[bg[pat].rgb2_min].b;
+        int r1_diff = rgb[bg[pat].rgb1_max].r - r1_min;
+        int g1_diff = rgb[bg[pat].rgb1_max].g - g1_min;
+        int b1_diff = rgb[bg[pat].rgb1_max].b - b1_min;
+        int r2_diff = rgb[bg[pat].rgb2_max].r - r2_min;
+        int g2_diff = rgb[bg[pat].rgb2_max].g - g2_min;
+        int b2_diff = rgb[bg[pat].rgb2_max].b - b2_min;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            even_odd_vert = (int)((row / bgscale) & 1);
+            r1 = r1_min + (r1_diff * yidx) / yidx_max;
+            g1 = g1_min + (g1_diff * yidx) / yidx_max;
+            b1 = b1_min + (b1_diff * yidx) / yidx_max;
+            r1_inv = r1_min + (r1_diff * (yidx_max-yidx)) / yidx_max;
+            g1_inv = g1_min + (g1_diff * (yidx_max-yidx)) / yidx_max;
+            b1_inv = b1_min + (b1_diff * (yidx_max-yidx)) / yidx_max;
+            r2 = r2_min + (r2_diff * yidx) / yidx_max;
+            g2 = g2_min + (g2_diff * yidx) / yidx_max;
+            b2 = b2_min + (b2_diff * yidx) / yidx_max;
+            r2_inv = r2_min + (r2_diff * (yidx_max-yidx)) / yidx_max;
+            g2_inv = g2_min + (g2_diff * (yidx_max-yidx)) / yidx_max;
+            b2_inv = b2_min + (b2_diff * (yidx_max-yidx)) / yidx_max;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                even_odd_horiz = (int)((i / bgscale) & 1);
+                even_odd = even_odd_vert ^ even_odd_horiz;
+                invert_column =
+                  (even_odd_horiz && (bg[pat].type & 0x10));
+                if (even_odd == 0) {        /* gradient #1 */
+                    if (invert_column) {
+                        *dest++ = r1_inv;
+                        *dest++ = g1_inv;
+                        *dest++ = b1_inv;
+                    } else {
+                        *dest++ = r1;
+                        *dest++ = g1;
+                        *dest++ = b1;
+                    }
+                } else {                    /* gradient #2 */
+                    if ((invert_column && invert_gradient2) ||
+                        (!invert_column && !invert_gradient2))
+                    {
+                        *dest++ = r2;       /* not inverted or */
+                        *dest++ = g2;       /*  doubly inverted */
+                        *dest++ = b2;
+                    } else {
+                        *dest++ = r2_inv;
+                        *dest++ = g2_inv;   /* singly inverted */
+                        *dest++ = b2_inv;
+                    }
+                }
+            }
+        }
+/*---------------------------------------------------------------------------
+    Soft gradient-diamonds with scale = bgscale.  Code contributed by Adam
+    M. Costello.
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 1) {
+        hmax = (bgscale-1)/2;   /* half the max weight of a color */
+        max = 2*hmax;           /* the max weight of a color */
+        r1 = rgb[bg[pat].rgb1_max].r;
+        g1 = rgb[bg[pat].rgb1_max].g;
+        b1 = rgb[bg[pat].rgb1_max].b;
+        r2 = rgb[bg[pat].rgb2_max].r;
+        g2 = rgb[bg[pat].rgb2_max].g;
+        b2 = rgb[bg[pat].rgb2_max].b;
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            yidx = (int)(row % bgscale);
+            if (yidx > hmax)
+                yidx = bgscale-1 - yidx;
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                xidx = (int)(i % bgscale);
+                if (xidx > hmax)
+                    xidx = bgscale-1 - xidx;
+                k = xidx + yidx;
+                *dest++ = (k*r1 + (max-k)*r2) / max;
+                *dest++ = (k*g1 + (max-k)*g2) / max;
+                *dest++ = (k*b1 + (max-k)*b2) / max;
+            }
+        }
+/*---------------------------------------------------------------------------
+    Radial "starburst" with azimuthal sinusoids; [eventually number of sinu-
+    soids will equal bgscale?].  This one is slow but very cool.  Code con-
+    tributed by Pieter S. van der Meulen (originally in Smalltalk).
+  ---------------------------------------------------------------------------*/
+    } else if ((bg[pat].type & 0x07) == 2) {
+        uch ch;
+        int ii, x, y, hw, hh, grayspot;
+        double freq, rotate, saturate, gray, intensity;
+        double angle=0.0, aoffset=0.0, maxDist, dist;
+        double red=0.0, green=0.0, blue=0.0, hue, s, v, f, p, q, t;
+        hh = (int)(rpng2_info.height / 2);
+        hw = (int)(rpng2_info.width / 2);
+        /* variables for radial waves:
+         *   aoffset:  number of degrees to rotate hue [CURRENTLY NOT USED]
+         *   freq:  number of color beams originating from the center
+         *   grayspot:  size of the graying center area (anti-alias)
+         *   rotate:  rotation of the beams as a function of radius
+         *   saturate:  saturation of beams' shape azimuthally
+         */
+        angle = CLIP(angle, 0.0, 360.0);
+        grayspot = CLIP(bg[pat].bg_gray, 1, (hh + hw));
+        freq = MAX((double)bg[pat].bg_freq, 0.0);
+        saturate = (double)bg[pat].bg_bsat * 0.1;
+        rotate = (double)bg[pat].bg_brot * 0.1;
+        gray = 0.0;
+        intensity = 0.0;
+        maxDist = (double)((hw*hw) + (hh*hh));
+        for (row = 0;  row < rpng2_info.height;  ++row) {
+            y = (int)(row - hh);
+            dest = (char *)bg_data + row*bg_rowbytes;
+            for (i = 0;  i < rpng2_info.width;  ++i) {
+                x = (int)(i - hw);
+                angle = (x == 0)? PI_2 : atan((double)y / (double)x);
+                gray = (double)MAX(ABS(y), ABS(x)) / grayspot;
+                gray = MIN(1.0, gray);
+                dist = (double)((x*x) + (y*y)) / maxDist;
+                intensity = cos((angle+(rotate*dist*PI)) * freq) *
+                  gray * saturate;
+                intensity = (MAX(MIN(intensity,1.0),-1.0) + 1.0) * 0.5;
+                hue = (angle + PI) * INV_PI_360 + aoffset;
+                s = gray * ((double)(ABS(x)+ABS(y)) / (double)(hw + hh));
+                s = MIN(MAX(s,0.0), 1.0);
+                v = MIN(MAX(intensity,0.0), 1.0);
+                if (s == 0.0) {
+                    ch = (uch)(v * 255.0);
+                    *dest++ = ch;
+                    *dest++ = ch;
+                    *dest++ = ch;
+                } else {
+                    if ((hue < 0.0) || (hue >= 360.0))
+                        hue -= (((int)(hue / 360.0)) * 360.0);
+                    hue /= 60.0;
+                    ii = (int)hue;
+                    f = hue - (double)ii;
+                    p = (1.0 - s) * v;
+                    q = (1.0 - (s * f)) * v;
+                    t = (1.0 - (s * (1.0 - f))) * v;
+                    if      (ii == 0) { red = v; green = t; blue = p; }
+                    else if (ii == 1) { red = q; green = v; blue = p; }
+                    else if (ii == 2) { red = p; green = v; blue = t; }
+                    else if (ii == 3) { red = p; green = q; blue = v; }
+                    else if (ii == 4) { red = t; green = p; blue = v; }
+                    else if (ii == 5) { red = v; green = p; blue = q; }
+                    *dest++ = (uch)(red * 255.0);
+                    *dest++ = (uch)(green * 255.0);
+                    *dest++ = (uch)(blue * 255.0);
+                }
+            }
+        }
+    }
+} /* end function rpng2_x_reload_bg_image() */
+static int is_number(char *p)
+{
+    while (*p) {
+        if (!isdigit(*p))
+            return FALSE;
+        ++p;
+    }
+    return TRUE;
+}
+#endif /* FEATURE_LOOP */
+static void rpng2_x_cleanup(void)
+{
+    if (bg_image && bg_data) {
+        free(bg_data);
+        bg_data = NULL;
+    }
+    if (rpng2_info.image_data) {
+        free(rpng2_info.image_data);
+        rpng2_info.image_data = NULL;
+    }
+    if (rpng2_info.row_pointers) {
+        free(rpng2_info.row_pointers);
+        rpng2_info.row_pointers = NULL;
+    }
+    if (ximage) {
+        if (ximage->data) {
+            free(ximage->data);           /* we allocated it, so we free it */
+            ximage->data = (char *)NULL;  /*  instead of XDestroyImage() */
+        }
+        XDestroyImage(ximage);
+        ximage = NULL;
+    }
+    if (have_gc)
+        XFreeGC(display, gc);
+    if (have_window)
+        XDestroyWindow(display, window);
+    if (have_colormap)
+        XFreeColormap(display, colormap);
+    if (have_nondefault_visual)
+        XFree(visual_list);
+}
+static int rpng2_x_msb(ulg u32val)
+{
+    int i;
+    for (i = 31;  i >= 0;  --i) {
+        if (u32val & 0x80000000L)
+            break;
+        u32val <<= 1;
+    }
+    return i;
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/toucan.png b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/toucan.png
new file mode 100644
index 0000000..03960d4
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/toucan.png
Binary files differ
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/wpng.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/wpng.c
new file mode 100644
index 0000000..30372a3
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/wpng.c
@@ -0,0 +1,853 @@
+/*---------------------------------------------------------------------------
+   wpng - simple PNG-writing program                                 wpng.c
+   This program converts certain NetPBM binary files (grayscale and RGB,
+   maxval = 255) to PNG.  Non-interlaced PNGs are written progressively;
+   interlaced PNGs are read and written in one memory-intensive blast.
+   Thanks to Jean-loup Gailly for providing the necessary trick to read
+   interactive text from the keyboard while stdin is redirected.  Thanks
+   to Cosmin Truta for Cygwin fixes.
+   NOTE:  includes provisional support for PNM type "8" (portable alphamap)
+          images, presumed to be a 32-bit interleaved RGBA format; no pro-
+          vision for possible interleaved grayscale+alpha (16-bit) format.
+          THIS IS UNLIKELY TO BECOME AN OFFICIAL NETPBM ALPHA FORMAT!
+   to do:
+    - delete output file if quit before calling any writepng routines
+    - process backspace with -text option under DOS/Win? (currently get ^H)
+  ---------------------------------------------------------------------------
+   Changelog:
+    - 1.01:  initial public release
+    - 1.02:  modified to allow abbreviated options
+    - 1.03:  removed extraneous character from usage screen; fixed bug in
+              command-line parsing
+    - 1.04:  fixed DOS/OS2/Win32 detection, including partial Cygwin fix
+              (see http://home.att.net/~perlspinr/diffs/GregBook_cygwin.diff)
+    - 2.00:  dual-licensed (added GNU GPL)
+        [REPORTED BUG (win32 only):  "contrib/gregbook/wpng.c - cmd line
+         dose not work!  In order to do something useful I needed to redirect
+         both input and output, with cygwin and with bcc32 as well.  Under
+         Linux, the same wpng appears to work fine.  I don't know what is
+         the problem."]
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#define PROGNAME  "wpng"
+#define VERSION   "2.00 of 2 June 2007"
+#define APPNAME   "Simple PGM/PPM/PAM to PNG Converter"
+#if defined(__MSDOS__) || defined(__OS2__)
+#  define DOS_OS2_W32
+#elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
+#  ifndef __GNUC__   /* treat Win32 native ports of gcc as Unix environments */
+#    define DOS_OS2_W32
+#  endif
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <setjmp.h>     /* for jmpbuf declaration in writepng.h */
+#include <time.h>
+#ifdef DOS_OS2_W32
+#  include <io.h>       /* for isatty(), setmode() prototypes */
+#  include <fcntl.h>    /* O_BINARY for fdopen() without text translation */
+#  ifdef __EMX__
+#    ifndef getch
+#      define getch() _read_kbd(0, 1, 0)    /* need getche() */
+#    endif
+#  else /* !__EMX__ */
+#    ifdef __GO32__
+#      include <pc.h>
+#      define getch() getkey()  /* GRR:  need getche() */
+#    else
+#      include <conio.h>        /* for getche() console input */
+#    endif
+#  endif /* ?__EMX__ */
+#  define FGETS(buf,len,stream)  dos_kbd_gets(buf,len)
+#else
+#  include <unistd.h>           /* for isatty() prototype */
+#  define FGETS fgets
+#endif
+/* #define DEBUG  :  this enables the Trace() macros */
+/* #define FORBID_LATIN1_CTRL  :  this requires the user to re-enter any
+   text that includes control characters discouraged by the PNG spec; text
+   that includes an escape character (27) must be re-entered regardless */
+#include "writepng.h"   /* typedefs, common macros, writepng prototypes */
+/* local prototypes */
+static int  wpng_isvalid_latin1(uch *p, int len);
+static void wpng_cleanup(void);
+#ifdef DOS_OS2_W32
+   static char *dos_kbd_gets(char *buf, int len);
+#endif
+static mainprog_info wpng_info;   /* lone global */
+int main(int argc, char **argv)
+{
+#ifndef DOS_OS2_W32
+    FILE *keybd;
+#endif
+#ifdef sgi
+    FILE *tmpfile;      /* or we could just use keybd, since no overlap */
+    char tmpline[80];
+#endif
+    char *inname = NULL, outname[256];
+    char *p, pnmchar, pnmline[256];
+    char *bgstr, *textbuf = NULL;
+    ulg rowbytes;
+    int rc, len = 0;
+    int error = 0;
+    int text = FALSE;
+    int maxval;
+    double LUT_exponent;                /* just the lookup table */
+    double CRT_exponent = 2.2;          /* just the monitor */
+    double default_display_exponent;    /* whole display system */
+    double default_gamma = 0.0;
+    wpng_info.infile = NULL;
+    wpng_info.outfile = NULL;
+    wpng_info.image_data = NULL;
+    wpng_info.row_pointers = NULL;
+    wpng_info.filter = FALSE;
+    wpng_info.interlaced = FALSE;
+    wpng_info.have_bg = FALSE;
+    wpng_info.have_time = FALSE;
+    wpng_info.have_text = 0;
+    wpng_info.gamma = 0.0;
+    /* First get the default value for our display-system exponent, i.e.,
+     * the product of the CRT exponent and the exponent corresponding to
+     * the frame-buffer's lookup table (LUT), if any.  If the PNM image
+     * looks correct on the user's display system, its file gamma is the
+     * inverse of this value.  (Note that this is not an exhaustive list
+     * of LUT values--e.g., OpenStep has a lot of weird ones--but it should
+     * cover 99% of the current possibilities.  This section must ensure
+     * that default_display_exponent is positive.) */
+#if defined(NeXT)
+    /* third-party utilities can modify the default LUT exponent */
+    LUT_exponent = 1.0 / 2.2;
+    /*
+    if (some_next_function_that_returns_gamma(&next_gamma))
+        LUT_exponent = 1.0 / next_gamma;
+     */
+#elif defined(sgi)
+    LUT_exponent = 1.0 / 1.7;
+    /* there doesn't seem to be any documented function to
+     * get the "gamma" value, so we do it the hard way */
+    tmpfile = fopen("/etc/config/system.glGammaVal", "r");
+    if (tmpfile) {
+        double sgi_gamma;
+        fgets(tmpline, 80, tmpfile);
+        fclose(tmpfile);
+        sgi_gamma = atof(tmpline);
+        if (sgi_gamma > 0.0)
+            LUT_exponent = 1.0 / sgi_gamma;
+    }
+#elif defined(Macintosh)
+    LUT_exponent = 1.8 / 2.61;
+    /*
+    if (some_mac_function_that_returns_gamma(&mac_gamma))
+        LUT_exponent = mac_gamma / 2.61;
+     */
+#else
+    LUT_exponent = 1.0;   /* assume no LUT:  most PCs */
+#endif
+    /* the defaults above give 1.0, 1.3, 1.5 and 2.2, respectively: */
+    default_display_exponent = LUT_exponent * CRT_exponent;
+    /* If the user has set the SCREEN_GAMMA environment variable as suggested
+     * (somewhat imprecisely) in the libpng documentation, use that; otherwise
+     * use the default value we just calculated.  Either way, the user may
+     * override this via a command-line option. */
+    if ((p = getenv("SCREEN_GAMMA")) != NULL) {
+        double exponent = atof(p);
+        if (exponent > 0.0)
+            default_gamma = 1.0 / exponent;
+    }
+    if (default_gamma == 0.0)
+        default_gamma = 1.0 / default_display_exponent;
+    /* Now parse the command line for options and the PNM filename. */
+    while (*++argv && !error) {
+        if (!strncmp(*argv, "-i", 2)) {
+            wpng_info.interlaced = TRUE;
+        } else if (!strncmp(*argv, "-time", 3)) {
+            wpng_info.modtime = time(NULL);
+            wpng_info.have_time = TRUE;
+        } else if (!strncmp(*argv, "-text", 3)) {
+            text = TRUE;
+        } else if (!strncmp(*argv, "-gamma", 2)) {
+            if (!*++argv)
+                ++error;
+            else {
+                wpng_info.gamma = atof(*argv);
+                if (wpng_info.gamma <= 0.0)
+                    ++error;
+                else if (wpng_info.gamma > 1.01)
+                    fprintf(stderr, PROGNAME
+                      " warning:  file gammas are usually less than 1.0\n");
+            }
+        } else if (!strncmp(*argv, "-bgcolor", 4)) {
+            if (!*++argv)
+                ++error;
+            else {
+                bgstr = *argv;
+                if (strlen(bgstr) != 7 || bgstr[0] != '#')
+                    ++error;
+                else {
+                    unsigned r, g, b;  /* this way quiets compiler warnings */
+                    sscanf(bgstr+1, "%2x%2x%2x", &r, &g, &b);
+                    wpng_info.bg_red   = (uch)r;
+                    wpng_info.bg_green = (uch)g;
+                    wpng_info.bg_blue  = (uch)b;
+                    wpng_info.have_bg = TRUE;
+                }
+            }
+        } else {
+            if (**argv != '-') {
+                inname = *argv;
+                if (argv[1])   /* shouldn't be any more args after filename */
+                    ++error;
+            } else
+                ++error;   /* not expecting any other options */
+        }
+    }
+    /* open the input and output files, or register an error and abort */
+    if (!inname) {
+        if (isatty(0)) {
+            fprintf(stderr, PROGNAME
+              ":  must give input filename or provide image data via stdin\n");
+            ++error;
+        } else {
+#ifdef DOS_OS2_W32
+            /* some buggy C libraries require BOTH setmode() and fdopen(bin) */
+            setmode(fileno(stdin), O_BINARY);
+            setmode(fileno(stdout), O_BINARY);
+#endif
+            if ((wpng_info.infile = fdopen(fileno(stdin), "rb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdin in binary mode\n");
+                ++error;
+            } else
+            if ((wpng_info.outfile = fdopen(fileno(stdout), "wb")) == NULL) {
+                fprintf(stderr, PROGNAME
+                  ":  unable to reopen stdout in binary mode\n");
+                fclose(wpng_info.infile);
+                ++error;
+            } else
+                wpng_info.filter = TRUE;
+        }
+    } else if ((len = strlen(inname)) > 250) {
+        fprintf(stderr, PROGNAME ":  input filename is too long [%d chars]\n",
+          len);
+        ++error;
+    } else if (!(wpng_info.infile = fopen(inname, "rb"))) {
+        fprintf(stderr, PROGNAME ":  can't open input file [%s]\n", inname);
+        ++error;
+    }
+    if (!error) {
+        fgets(pnmline, 256, wpng_info.infile);
+        if (pnmline[0] != 'P' || ((pnmchar = pnmline[1]) != '5' &&
+            pnmchar != '6' && pnmchar != '8'))
+        {
+            fprintf(stderr, PROGNAME
+              ":  input file [%s] is not a binary PGM, PPM or PAM file\n",
+              inname);
+            ++error;
+        } else {
+            wpng_info.pnmtype = (int)(pnmchar - '0');
+            if (wpng_info.pnmtype != 8)
+                wpng_info.have_bg = FALSE;  /* no need for bg if opaque */
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* lose any comments */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%ld %ld", &wpng_info.width, &wpng_info.height);
+            do {
+                fgets(pnmline, 256, wpng_info.infile);  /* more comment lines */
+            } while (pnmline[0] == '#');
+            sscanf(pnmline, "%d", &maxval);
+            if (wpng_info.width <= 0L || wpng_info.height <= 0L ||
+                maxval != 255)
+            {
+                fprintf(stderr, PROGNAME
+                  ":  only positive width/height, maxval == 255 allowed \n");
+                ++error;
+            }
+            wpng_info.sample_depth = 8;  /* <==> maxval 255 */
+            if (!wpng_info.filter) {
+                /* make outname from inname */
+                if ((p = strrchr(inname, '.')) == NULL ||
+                    (p - inname) != (len - 4))
+                {
+                    strcpy(outname, inname);
+                    strcpy(outname+len, ".png");
+                } else {
+                    len -= 4;
+                    strncpy(outname, inname, len);
+                    strcpy(outname+len, ".png");
+                }
+                /* check if outname already exists; if not, open */
+                if ((wpng_info.outfile = fopen(outname, "rb")) != NULL) {
+                    fprintf(stderr, PROGNAME ":  output file exists [%s]\n",
+                      outname);
+                    fclose(wpng_info.outfile);
+                    ++error;
+                } else if (!(wpng_info.outfile = fopen(outname, "wb"))) {
+                    fprintf(stderr, PROGNAME ":  can't open output file [%s]\n",
+                      outname);
+                    ++error;
+                }
+            }
+        }
+        if (error) {
+            fclose(wpng_info.infile);
+            wpng_info.infile = NULL;
+            if (wpng_info.filter) {
+                fclose(wpng_info.outfile);
+                wpng_info.outfile = NULL;
+            }
+        }
+    }
+    /* if we had any errors, print usage and die horrible death...arrr! */
+    if (error) {
+        fprintf(stderr, "\n%s %s:  %s\n", PROGNAME, VERSION, APPNAME);
+        writepng_version_info();
+        fprintf(stderr, "\n"
+"Usage:  %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] pnmfile\n"
+"or: ... | %s [-gamma exp] [-bgcolor bg] [-text] [-time] [-interlace] | ...\n"
+         "    exp \ttransfer-function exponent (``gamma'') of the image in\n"
+         "\t\t  floating-point format (e.g., ``%.5f''); if image looks\n"
+         "\t\t  correct on given display system, image gamma is equal to\n"
+         "\t\t  inverse of display-system exponent, i.e., 1 / (LUT * CRT)\n"
+         "\t\t  (where LUT = lookup-table exponent and CRT = CRT exponent;\n"
+         "\t\t  first varies, second is usually 2.2, all are positive)\n"
+         "    bg  \tdesired background color for alpha-channel images, in\n"
+         "\t\t  7-character hex RGB format (e.g., ``#ff7700'' for orange:\n"
+         "\t\t  same as HTML colors)\n"
+         "    -text\tprompt interactively for text info (tEXt chunks)\n"
+         "    -time\tinclude a tIME chunk (last modification time)\n"
+         "    -interlace\twrite interlaced PNG image\n"
+         "\n"
+"pnmfile or stdin must be a binary PGM (`P5'), PPM (`P6') or (extremely\n"
+"unofficial and unsupported!) PAM (`P8') file.  Currently it is required\n"
+"to have maxval == 255 (i.e., no scaling).  If pnmfile is specified, it\n"
+"is converted to the corresponding PNG file with the same base name but a\n"
+"``.png'' extension; files read from stdin are converted and sent to stdout.\n"
+"The conversion is progressive (low memory usage) unless interlacing is\n"
+"requested; in that case the whole image will be buffered in memory and\n"
+"written in one call.\n"
+         "\n", PROGNAME, PROGNAME, default_gamma);
+        exit(1);
+    }
+    /* prepare the text buffers for libpng's use; note that even though
+     * PNG's png_text struct includes a length field, we don't have to fill
+     * it out */
+    if (text &&
+#ifndef DOS_OS2_W32
+        (keybd = fdopen(fileno(stderr), "r")) != NULL &&
+#endif
+        (textbuf = (char *)malloc((5 + 9)*75)) != NULL)
+    {
+        int i, valid, result;
+        fprintf(stderr,
+          "Enter text info (no more than 72 characters per line);\n");
+        fprintf(stderr, "to skip a field, hit the <Enter> key.\n");
+        /* note:  just <Enter> leaves len == 1 */
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_TITLE_OFFSET;
+            fprintf(stderr, "  Title: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.title = p;
+                wpng_info.have_text |= TEXT_TITLE;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_TITLE;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_TITLE;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_AUTHOR_OFFSET;
+            fprintf(stderr, "  Author: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.author = p;
+                wpng_info.have_text |= TEXT_AUTHOR;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_AUTHOR;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_AUTHOR;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_DESC_OFFSET;
+            fprintf(stderr, "  Description (up to 9 lines):\n");
+            for (i = 1;  i < 10;  ++i) {
+                fprintf(stderr, "    [%d] ", i);
+                fflush(stderr);
+                if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1)
+                    p += len;   /* now points at NULL; char before is newline */
+                else
+                    break;
+            }
+            if ((len = p - (textbuf + TEXT_DESC_OFFSET)) > 1) {
+                if (p[-1] == '\n') {
+                    p[-1] = '\0';
+                    --len;
+                }
+                wpng_info.desc = textbuf + TEXT_DESC_OFFSET;
+                wpng_info.have_text |= TEXT_DESC;
+                p = textbuf + TEXT_DESC_OFFSET;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_DESC;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_DESC;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_COPY_OFFSET;
+            fprintf(stderr, "  Copyright: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.copyright = p;
+                wpng_info.have_text |= TEXT_COPY;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_COPY;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_COPY;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_EMAIL_OFFSET;
+            fprintf(stderr, "  E-mail: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.email = p;
+                wpng_info.have_text |= TEXT_EMAIL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_EMAIL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_EMAIL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+        do {
+            valid = TRUE;
+            p = textbuf + TEXT_URL_OFFSET;
+            fprintf(stderr, "  URL: ");
+            fflush(stderr);
+            if (FGETS(p, 74, keybd) && (len = strlen(p)) > 1) {
+                if (p[len-1] == '\n')
+                    p[--len] = '\0';
+                wpng_info.url = p;
+                wpng_info.have_text |= TEXT_URL;
+                if ((result = wpng_isvalid_latin1((uch *)p, len)) >= 0) {
+                    fprintf(stderr, "    " PROGNAME " warning:  character code"
+                      " %u is %sdiscouraged by the PNG\n    specification "
+                      "[first occurrence was at character position #%d]\n",
+                      (unsigned)p[result], (p[result] == 27)? "strongly " : "",
+                      result+1);
+                    fflush(stderr);
+#ifdef FORBID_LATIN1_CTRL
+                    wpng_info.have_text &= ~TEXT_URL;
+                    valid = FALSE;
+#else
+                    if (p[result] == 27) {    /* escape character */
+                        wpng_info.have_text &= ~TEXT_URL;
+                        valid = FALSE;
+                    }
+#endif
+                }
+            }
+        } while (!valid);
+#ifndef DOS_OS2_W32
+        fclose(keybd);
+#endif
+    } else if (text) {
+        fprintf(stderr, PROGNAME ":  unable to allocate memory for text\n");
+        text = FALSE;
+        wpng_info.have_text = 0;
+    }
+    /* allocate libpng stuff, initialize transformations, write pre-IDAT data */
+    if ((rc = writepng_init(&wpng_info)) != 0) {
+        switch (rc) {
+            case 2:
+                fprintf(stderr, PROGNAME
+                  ":  libpng initialization problem (longjmp)\n");
+                break;
+            case 4:
+                fprintf(stderr, PROGNAME ":  insufficient memory\n");
+                break;
+            case 11:
+                fprintf(stderr, PROGNAME
+                  ":  internal logic error (unexpected PNM type)\n");
+                break;
+            default:
+                fprintf(stderr, PROGNAME
+                  ":  unknown writepng_init() error\n");
+                break;
+        }
+        exit(rc);
+    }
+    /* free textbuf, since it's a completely local variable and all text info
+     * has just been written to the PNG file */
+    if (text && textbuf) {
+        free(textbuf);
+        textbuf = NULL;
+    }
+    /* calculate rowbytes on basis of image type; note that this becomes much
+     * more complicated if we choose to support PBM type, ASCII PNM types, or
+     * 16-bit-per-sample binary data [currently not an official NetPBM type] */
+    if (wpng_info.pnmtype == 5)
+        rowbytes = wpng_info.width;
+    else if (wpng_info.pnmtype == 6)
+        rowbytes = wpng_info.width * 3;
+    else /* if (wpng_info.pnmtype == 8) */
+        rowbytes = wpng_info.width * 4;
+    /* read and write the image, either in its entirety (if writing interlaced
+     * PNG) or row by row (if non-interlaced) */
+    fprintf(stderr, "Encoding image data...\n");
+    fflush(stderr);
+    if (wpng_info.interlaced) {
+        long i;
+        ulg bytes;
+        ulg image_bytes = rowbytes * wpng_info.height;   /* overflow? */
+        wpng_info.image_data = (uch *)malloc(image_bytes);
+        wpng_info.row_pointers = (uch **)malloc(wpng_info.height*sizeof(uch *));
+        if (wpng_info.image_data == NULL || wpng_info.row_pointers == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        for (i = 0;  i < wpng_info.height;  ++i)
+            wpng_info.row_pointers[i] = wpng_info.image_data + i*rowbytes;
+        bytes = fread(wpng_info.image_data, 1, image_bytes, wpng_info.infile);
+        if (bytes != image_bytes) {
+            fprintf(stderr, PROGNAME ":  expected %lu bytes, got %lu bytes\n",
+              image_bytes, bytes);
+            fprintf(stderr, "  (continuing anyway)\n");
+        }
+        if (writepng_encode_image(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME
+              ":  libpng problem (longjmp) while writing image data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+    } else /* not interlaced:  write progressively (row by row) */ {
+        long j;
+        ulg bytes;
+        wpng_info.image_data = (uch *)malloc(rowbytes);
+        if (wpng_info.image_data == NULL) {
+            fprintf(stderr, PROGNAME ":  insufficient memory for row data\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(5);
+        }
+        error = 0;
+        for (j = wpng_info.height;  j > 0L;  --j) {
+            bytes = fread(wpng_info.image_data, 1, rowbytes, wpng_info.infile);
+            if (bytes != rowbytes) {
+                fprintf(stderr, PROGNAME
+                  ":  expected %lu bytes, got %lu bytes (row %ld)\n", rowbytes,
+                  bytes, wpng_info.height-j);
+                ++error;
+                break;
+            }
+            if (writepng_encode_row(&wpng_info) != 0) {
+                fprintf(stderr, PROGNAME
+                  ":  libpng problem (longjmp) while writing row %ld\n",
+                  wpng_info.height-j);
+                ++error;
+                break;
+            }
+        }
+        if (error) {
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+        if (writepng_encode_finish(&wpng_info) != 0) {
+            fprintf(stderr, PROGNAME ":  error on final libpng call\n");
+            writepng_cleanup(&wpng_info);
+            wpng_cleanup();
+            exit(2);
+        }
+    }
+    /* OK, we're done (successfully):  clean up all resources and quit */
+    fprintf(stderr, "Done.\n");
+    fflush(stderr);
+    writepng_cleanup(&wpng_info);
+    wpng_cleanup();
+    return 0;
+}
+static int wpng_isvalid_latin1(uch *p, int len)
+{
+    int i, result = -1;
+    for (i = 0;  i < len;  ++i) {
+        if (p[i] == 10 || (p[i] > 31 && p[i] < 127) || p[i] > 160)
+            continue;           /* character is completely OK */
+        if (result < 0 || (p[result] != 27 && p[i] == 27))
+            result = i;         /* mark location of first questionable one */
+    }                           /*  or of first escape character (bad) */
+    return result;
+}
+static void wpng_cleanup(void)
+{
+    if (wpng_info.outfile) {
+        fclose(wpng_info.outfile);
+        wpng_info.outfile = NULL;
+    }
+    if (wpng_info.infile) {
+        fclose(wpng_info.infile);
+        wpng_info.infile = NULL;
+    }
+    if (wpng_info.image_data) {
+        free(wpng_info.image_data);
+        wpng_info.image_data = NULL;
+    }
+    if (wpng_info.row_pointers) {
+        free(wpng_info.row_pointers);
+        wpng_info.row_pointers = NULL;
+    }
+}
+#ifdef DOS_OS2_W32
+static char *dos_kbd_gets(char *buf, int len)
+{
+    int ch, count=0;
+    do {
+        buf[count++] = ch = getche();
+    } while (ch != '\r' && count < len-1);
+    buf[count--] = '\0';        /* terminate string */
+    if (buf[count] == '\r')     /* Enter key makes CR, so change to newline */
+        buf[count] = '\n';
+    fprintf(stderr, "\n");      /* Enter key does *not* cause a newline */
+    fflush(stderr);
+    return buf;
+}
+#endif /* DOS_OS2_W32 */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.c
new file mode 100644
index 0000000..8373c16
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.c
@@ -0,0 +1,400 @@
+/*---------------------------------------------------------------------------
+   wpng - simple PNG-writing program                             writepng.c
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#include <stdlib.h>     /* for exit() prototype */
+#include "png.h"        /* libpng header; includes zlib.h and setjmp.h */
+#include "writepng.h"   /* typedefs, common macros, public prototypes */
+/* local prototype */
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg);
+void writepng_version_info(void)
+{
+  fprintf(stderr, "   Compiled with libpng %s; using libpng %s.\n",
+    PNG_LIBPNG_VER_STRING, png_libpng_ver);
+  fprintf(stderr, "   Compiled with zlib %s; using zlib %s.\n",
+    ZLIB_VERSION, zlib_version);
+}
+/* returns 0 for success, 2 for libpng problem, 4 for out of memory, 11 for
+ *  unexpected pnmtype; note that outfile might be stdout */
+int writepng_init(mainprog_info *mainprog_ptr)
+{
+    png_structp  png_ptr;       /* note:  temporary variables! */
+    png_infop  info_ptr;
+    int color_type, interlace_type;
+    /* could also replace libpng warning-handler (final NULL), but no need: */
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, mainprog_ptr,
+      writepng_error_handler, NULL);
+    if (!png_ptr)
+        return 4;   /* out of memory */
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_write_struct(&png_ptr, NULL);
+        return 4;   /* out of memory */
+    }
+    /* setjmp() must be called in every function that calls a PNG-writing
+     * libpng function, unless an alternate error handler was installed--
+     * but compatible error handlers must either use longjmp() themselves
+     * (as in this program) or some other method to return control to
+     * application code, so here we go: */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 2;
+    }
+    /* make sure outfile is (re)opened in BINARY mode */
+    png_init_io(png_ptr, mainprog_ptr->outfile);
+    /* set the compression levels--in general, always want to leave filtering
+     * turned on (except for palette images) and allow all of the filters,
+     * which is the default; want 32K zlib window, unless entire image buffer
+     * is 16K or smaller (unknown here)--also the default; usually want max
+     * compression (NOT the default); and remaining compression flags should
+     * be left alone */
+    png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
+/*
+    >> this is default for no filtering; Z_FILTERED is default otherwise:
+    png_set_compression_strategy(png_ptr, Z_DEFAULT_STRATEGY);
+    >> these are all defaults:
+    png_set_compression_mem_level(png_ptr, 8);
+    png_set_compression_window_bits(png_ptr, 15);
+    png_set_compression_method(png_ptr, 8);
+ */
+    /* set the image parameters appropriately */
+    if (mainprog_ptr->pnmtype == 5)
+        color_type = PNG_COLOR_TYPE_GRAY;
+    else if (mainprog_ptr->pnmtype == 6)
+        color_type = PNG_COLOR_TYPE_RGB;
+    else if (mainprog_ptr->pnmtype == 8)
+        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+    else {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return 11;
+    }
+    interlace_type = mainprog_ptr->interlaced? PNG_INTERLACE_ADAM7 :
+                                               PNG_INTERLACE_NONE;
+    png_set_IHDR(png_ptr, info_ptr, mainprog_ptr->width, mainprog_ptr->height,
+      mainprog_ptr->sample_depth, color_type, interlace_type,
+      PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+    if (mainprog_ptr->gamma > 0.0)
+        png_set_gAMA(png_ptr, info_ptr, mainprog_ptr->gamma);
+    if (mainprog_ptr->have_bg) {   /* we know it's RGBA, not gray+alpha */
+        png_color_16  background;
+        background.red = mainprog_ptr->bg_red;
+        background.green = mainprog_ptr->bg_green;
+        background.blue = mainprog_ptr->bg_blue;
+        png_set_bKGD(png_ptr, info_ptr, &background);
+    }
+    if (mainprog_ptr->have_time) {
+        png_time  modtime;
+        png_convert_from_time_t(&modtime, mainprog_ptr->modtime);
+        png_set_tIME(png_ptr, info_ptr, &modtime);
+    }
+    if (mainprog_ptr->have_text) {
+        png_text  text[6];
+        int  num_text = 0;
+        if (mainprog_ptr->have_text & TEXT_TITLE) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Title";
+            text[num_text].text = mainprog_ptr->title;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_AUTHOR) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Author";
+            text[num_text].text = mainprog_ptr->author;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_DESC) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Description";
+            text[num_text].text = mainprog_ptr->desc;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_COPY) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "Copyright";
+            text[num_text].text = mainprog_ptr->copyright;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_EMAIL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "E-mail";
+            text[num_text].text = mainprog_ptr->email;
+            ++num_text;
+        }
+        if (mainprog_ptr->have_text & TEXT_URL) {
+            text[num_text].compression = PNG_TEXT_COMPRESSION_NONE;
+            text[num_text].key = "URL";
+            text[num_text].text = mainprog_ptr->url;
+            ++num_text;
+        }
+        png_set_text(png_ptr, info_ptr, text, num_text);
+    }
+    /* write all chunks up to (but not including) first IDAT */
+    png_write_info(png_ptr, info_ptr);
+    /* if we wanted to write any more text info *after* the image data, we
+     * would set up text struct(s) here and call png_set_text() again, with
+     * just the new data; png_set_tIME() could also go here, but it would
+     * have no effect since we already called it above (only one tIME chunk
+     * allowed) */
+    /* set up the transformations:  for now, just pack low-bit-depth pixels
+     * into bytes (one, two or four pixels per byte) */
+    png_set_packing(png_ptr);
+/*  png_set_shift(png_ptr, &sig_bit);  to scale low-bit-depth values */
+    /* make sure we save our pointers for use in writepng_encode_image() */
+    mainprog_ptr->png_ptr = png_ptr;
+    mainprog_ptr->info_ptr = info_ptr;
+    /* OK, that's all we need to do for now; return happy */
+    return 0;
+}
+/* returns 0 for success, 2 for libpng (longjmp) problem */
+int writepng_encode_image(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+    /* and now we just write the whole image; libpng takes care of interlacing
+     * for us */
+    png_write_image(png_ptr, mainprog_ptr->row_pointers);
+    /* since that's it, we also close out the end of the PNG file now--if we
+     * had any text or time info to write after the IDATs, second argument
+     * would be info_ptr, but we optimize slightly by sending NULL pointer: */
+    png_write_end(png_ptr, NULL);
+    return 0;
+}
+/* returns 0 if succeeds, 2 if libpng problem */
+int writepng_encode_row(mainprog_info *mainprog_ptr)  /* NON-interlaced only! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+    /* image_data points at our one row of image data */
+    png_write_row(png_ptr, mainprog_ptr->image_data);
+    return 0;
+}
+/* returns 0 if succeeds, 2 if libpng problem */
+int writepng_encode_finish(mainprog_info *mainprog_ptr)   /* NON-interlaced! */
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    /* as always, setjmp() must be called in every function that calls a
+     * PNG-writing libpng function */
+    if (setjmp(mainprog_ptr->jmpbuf)) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        mainprog_ptr->png_ptr = NULL;
+        mainprog_ptr->info_ptr = NULL;
+        return 2;
+    }
+    /* close out PNG file; if we had any text or time info to write after
+     * the IDATs, second argument would be info_ptr: */
+    png_write_end(png_ptr, NULL);
+    return 0;
+}
+void writepng_cleanup(mainprog_info *mainprog_ptr)
+{
+    png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr;
+    png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr;
+    if (png_ptr && info_ptr)
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+}
+static void writepng_error_handler(png_structp png_ptr, png_const_charp msg)
+{
+    mainprog_info  *mainprog_ptr;
+    /* This function, aside from the extra step of retrieving the "error
+     * pointer" (below) and the fact that it exists within the application
+     * rather than within libpng, is essentially identical to libpng's
+     * default error handler.  The second point is critical:  since both
+     * setjmp() and longjmp() are called from the same code, they are
+     * guaranteed to have compatible notions of how big a jmp_buf is,
+     * regardless of whether _BSD_SOURCE or anything else has (or has not)
+     * been defined. */
+    fprintf(stderr, "writepng libpng error: %s\n", msg);
+    fflush(stderr);
+    mainprog_ptr = png_get_error_ptr(png_ptr);
+    if (mainprog_ptr == NULL) {         /* we are completely hosed now */
+        fprintf(stderr,
+          "writepng severe error:  jmpbuf not recoverable; terminating.\n");
+        fflush(stderr);
+        exit(99);
+    }
+    /* Now we have our data structure we can use the information in it
+     * to return control to our own higher level code (all the points
+     * where 'setjmp' is called in this file.)  This will work with other
+     * error handling mechanisms as well - libpng always calls png_error
+     * when it can proceed no further, thus, so long as the error handler
+     * is intercepted, application code can do its own error recovery.
+     */
+    longjmp(mainprog_ptr->jmpbuf, 1);
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.h
new file mode 100644
index 0000000..904e4fb
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/gregbook/writepng.h
@@ -0,0 +1,133 @@
+/*---------------------------------------------------------------------------
+   wpng - simple PNG-writing program                             writepng.h
+  ---------------------------------------------------------------------------
+      Copyright (c) 1998-2007 Greg Roelofs.  All rights reserved.
+      This software is provided "as is," without warranty of any kind,
+      express or implied.  In no event shall the author or contributors
+      be held liable for any damages arising in any way from the use of
+      this software.
+      The contents of this file are DUAL-LICENSED.  You may modify and/or
+      redistribute this software according to the terms of one of the
+      following two licenses (at your option):
+      LICENSE 1 ("BSD-like with advertising clause"):
+      Permission is granted to anyone to use this software for any purpose,
+      including commercial applications, and to alter it and redistribute
+      it freely, subject to the following restrictions:
+      1. Redistributions of source code must retain the above copyright
+         notice, disclaimer, and this list of conditions.
+      2. Redistributions in binary form must reproduce the above copyright
+         notice, disclaimer, and this list of conditions in the documenta-
+         tion and/or other materials provided with the distribution.
+      3. All advertising materials mentioning features or use of this
+         software must display the following acknowledgment:
+            This product includes software developed by Greg Roelofs
+            and contributors for the book, "PNG: The Definitive Guide,"
+            published by O'Reilly and Associates.
+      LICENSE 2 (GNU GPL v2 or later):
+      This program is free software; you can redistribute it and/or modify
+      it under the terms of the GNU General Public License as published by
+      the Free Software Foundation; either version 2 of the License, or
+      (at your option) any later version.
+      This program is distributed in the hope that it will be useful,
+      but WITHOUT ANY WARRANTY; without even the implied warranty of
+      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+      GNU General Public License for more details.
+      You should have received a copy of the GNU General Public License
+      along with this program; if not, write to the Free Software Foundation,
+      Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  ---------------------------------------------------------------------------*/
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+#ifndef MAX
+#  define MAX(a,b)  ((a) > (b)? (a) : (b))
+#  define MIN(a,b)  ((a) < (b)? (a) : (b))
+#endif
+#ifdef DEBUG
+#  define Trace(x)  {fprintf x ; fflush(stderr); fflush(stdout);}
+#else
+#  define Trace(x)  ;
+#endif
+#define TEXT_TITLE    0x01
+#define TEXT_AUTHOR   0x02
+#define TEXT_DESC     0x04
+#define TEXT_COPY     0x08
+#define TEXT_EMAIL    0x10
+#define TEXT_URL      0x20
+#define TEXT_TITLE_OFFSET        0
+#define TEXT_AUTHOR_OFFSET      72
+#define TEXT_COPY_OFFSET     (2*72)
+#define TEXT_EMAIL_OFFSET    (3*72)
+#define TEXT_URL_OFFSET      (4*72)
+#define TEXT_DESC_OFFSET     (5*72)
+typedef unsigned char   uch;
+typedef unsigned short  ush;
+typedef unsigned long   ulg;
+typedef struct _mainprog_info {
+    double gamma;
+    long width;
+    long height;
+    time_t modtime;
+    FILE *infile;
+    FILE *outfile;
+    void *png_ptr;
+    void *info_ptr;
+    uch *image_data;
+    uch **row_pointers;
+    char *title;
+    char *author;
+    char *desc;
+    char *copyright;
+    char *email;
+    char *url;
+    int filter;    /* command-line-filter flag, not PNG row filter! */
+    int pnmtype;
+    int sample_depth;
+    int interlaced;
+    int have_bg;
+    int have_time;
+    int have_text;
+    jmp_buf jmpbuf;
+    uch bg_red;
+    uch bg_green;
+    uch bg_blue;
+} mainprog_info;
+/* prototypes for public functions in writepng.c */
+void writepng_version_info(void);
+int writepng_init(mainprog_info *mainprog_ptr);
+int writepng_encode_image(mainprog_info *mainprog_ptr);
+int writepng_encode_row(mainprog_info *mainprog_ptr);
+int writepng_encode_finish(mainprog_info *mainprog_ptr);
+void writepng_cleanup(mainprog_info *mainprog_ptr);
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c
new file mode 100644
index 0000000..c7068fa
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/libtests/pngvalid.c
@@ -0,0 +1,9837 @@
+/* pngvalid.c - validate libpng by constructing then reading png files.
+ *
+ * Last changed in libpng 1.5.8 [%RDATE%]
+ * Copyright (c) 2012 Glenn Randers-Pehrson
+ * Written by John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ *   This is a C program that is intended to be linked against libpng.  It
+ *   generates bitmaps internally, stores them as PNG files (using the
+ *   sequential write code) then reads them back (using the sequential
+ *   read code) and validates that the result has the correct data.
+ *
+ *   The program can be modified and extended to test the correctness of
+ *   transformations performed by libpng.
+ */
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1 /* For floating point */
+#define _GNU_SOURCE 1 /* For the floating point exception extension */
+#include <signal.h>
+#ifdef HAVE_FEENABLEEXCEPT
+#  include <fenv.h>
+#endif
+/* Define the following to use this test against your installed libpng, rather
+ * than the one being built here:
+ */
+#ifdef PNG_FREESTANDING_TESTS
+#  include <png.h>
+#else
+#  include "../../png.h"
+#endif
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the PNG_CONST. */
+typedef png_byte *png_const_bytep;
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+   -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+   -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+   (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+   (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+   ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+   ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+   ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+   ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+/* This comes from pnglibconf.h afer 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+   ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+#include "zlib.h"   /* For crc32 */
+#include <float.h>  /* For floating point constants */
+#include <stdlib.h> /* For malloc */
+#include <string.h> /* For memcpy, memset */
+#include <math.h>   /* For floor */
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+#  if defined(__GNUC__) || defined(_MSC_VER)
+#     define UNUSED(param) (void)param;
+#  else
+#     define UNUSED(param)
+#  endif
+#endif
+/***************************** EXCEPTION HANDLING *****************************/
+#include "../visupng/cexcept.h"
+#ifdef __cplusplus
+#  define this not_the_cpp_this
+#  define new not_the_cpp_new
+#  define voidcast(type, value) static_cast<type>(value)
+#else
+#  define voidcast(type, value) (value)
+#endif /* __cplusplus */
+struct png_store;
+define_exception_type(struct png_store*);
+/* The following are macros to reduce typing everywhere where the well known
+ * name 'the_exception_context' must be defined.
+ */
+#define anon_context(ps) struct exception_context *the_exception_context = \
+   &(ps)->exception_context
+#define context(ps,fault) anon_context(ps); png_store *fault
+/******************************* UTILITIES ************************************/
+/* Error handling is particularly problematic in production code - error
+ * handlers often themselves have bugs which lead to programs that detect
+ * minor errors crashing.  The following functions deal with one very
+ * common class of errors in error handlers - attempting to format error or
+ * warning messages into buffers that are too small.
+ */
+static size_t safecat(char *buffer, size_t bufsize, size_t pos,
+   PNG_CONST char *cat)
+{
+   while (pos < bufsize && cat != NULL && *cat != 0)
+      buffer[pos++] = *cat++;
+   if (pos >= bufsize)
+      pos = bufsize-1;
+   buffer[pos] = 0;
+   return pos;
+}
+static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
+{
+   char number[64];
+   sprintf(number, "%d", n);
+   return safecat(buffer, bufsize, pos, number);
+}
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
+    int precision)
+{
+   char number[64];
+   sprintf(number, "%.*f", precision, d);
+   return safecat(buffer, bufsize, pos, number);
+}
+#endif
+static PNG_CONST char invalid[] = "invalid";
+static PNG_CONST char sep[] = ": ";
+static PNG_CONST char *colour_types[8] =
+{
+   "grayscale", invalid, "truecolour", "indexed-colour",
+   "grayscale with alpha", invalid, "truecolour with alpha", invalid
+};
+/* Convert a double precision value to fixed point. */
+static png_fixed_point
+fix(double d)
+{
+   d = floor(d * PNG_FP_1 + .5);
+   return (png_fixed_point)d;
+}
+/* Generate random bytes.  This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture.  It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics".
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+   png_uint_32 u0 = seed[0], u1 = seed[1];
+   png_bytep bytes = voidcast(png_bytep, pv);
+   /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+    * bit-20.  The top 1 bit is in u1, the bottom 32 are in u0.
+    */
+   size_t i;
+   for (i=0; i<size; ++i)
+   {
+      /* First generate 8 new bits then shift them in at the end. */
+      png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+      u1 <<= 8;
+      u1 |= u0 >> 24;
+      u0 <<= 8;
+      u0 |= u;
+      *bytes++ = (png_byte)u;
+   }
+   seed[0] = u0;
+   seed[1] = u1;
+}
+static void
+make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
+{
+   make_random_bytes(seed, bytes, 4);
+}
+static void
+randomize(void *pv, size_t size)
+{
+   static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
+   make_random_bytes(random_seed, pv, size);
+}
+#define RANDOMIZE(this) randomize(&(this), sizeof (this))
+static unsigned int
+random_mod(unsigned int max)
+{
+   unsigned int x;
+   RANDOMIZE(x);
+   return x % max; /* 0 .. max-1 */
+}
+static int
+random_choice(void)
+{
+   unsigned char x;
+   RANDOMIZE(x);
+   return x & 1;
+}
+/* A numeric ID based on PNG file characteristics.  The 'do_interlace' field
+ * simply records whether pngvalid did the interlace itself or whether it
+ * was done by libpng.  Width and height must be less than 256.  'palette' is an
+ * index of the palette to use for formats with a palette (0 otherwise.)
+ */
+#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
+   ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
+    (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
+#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
+#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
+#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f))
+#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3))
+#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
+#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
+#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
+/* Utility to construct a standard name for a standard image. */
+static size_t
+standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
+    int bit_depth, int npalette, int interlace_type,
+    png_uint_32 w, png_uint_32 h, int do_interlace)
+{
+   pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
+   if (npalette > 0)
+   {
+      pos = safecat(buffer, bufsize, pos, "[");
+      pos = safecatn(buffer, bufsize, pos, npalette);
+      pos = safecat(buffer, bufsize, pos, "]");
+   }
+   pos = safecat(buffer, bufsize, pos, " ");
+   pos = safecatn(buffer, bufsize, pos, bit_depth);
+   pos = safecat(buffer, bufsize, pos, " bit");
+   if (interlace_type != PNG_INTERLACE_NONE)
+   {
+      pos = safecat(buffer, bufsize, pos, " interlaced");
+      if (do_interlace)
+         pos = safecat(buffer, bufsize, pos, "(pngvalid)");
+      else
+         pos = safecat(buffer, bufsize, pos, "(libpng)");
+   }
+   if (w > 0 || h > 0)
+   {
+      pos = safecat(buffer, bufsize, pos, " ");
+      pos = safecatn(buffer, bufsize, pos, w);
+      pos = safecat(buffer, bufsize, pos, "x");
+      pos = safecatn(buffer, bufsize, pos, h);
+   }
+   return pos;
+}
+static size_t
+standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
+{
+   return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
+      DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
+      WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
+}
+/* Convenience API and defines to list valid formats.  Note that 16 bit read and
+ * write support is required to do 16 bit read tests (we must be able to make a
+ * 16 bit image to test!)
+ */
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+#  define WRITE_BDHI 4
+#  ifdef PNG_READ_16BIT_SUPPORTED
+#     define READ_BDHI 4
+#     define DO_16BIT
+#  endif
+#else
+#  define WRITE_BDHI 3
+#endif
+#ifndef DO_16BIT
+#  define READ_BDHI 3
+#endif
+/* The following defines the number of different palettes to generate for
+ * each log bit depth of a colour type 3 standard image.
+ */
+#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16)
+static int
+next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number)
+{
+   if (*bit_depth == 0)
+   {
+      *colour_type = 0, *bit_depth = 1, *palette_number = 0;
+      return 1;
+   }
+   if (*colour_type == 3)
+   {
+      /* Add multiple palettes for colour type 3. */
+      if (++*palette_number < PALETTE_COUNT(*bit_depth))
+         return 1;
+      *palette_number = 0;
+   }
+   *bit_depth = (png_byte)(*bit_depth << 1);
+   /* Palette images are restricted to 8 bit depth */
+   if (*bit_depth <= 8
+#     ifdef DO_16BIT
+         || (*colour_type != 3 && *bit_depth <= 16)
+#     endif
+      )
+      return 1;
+   /* Move to the next color type, or return 0 at the end. */
+   switch (*colour_type)
+   {
+      case 0:
+         *colour_type = 2;
+         *bit_depth = 8;
+         return 1;
+      case 2:
+         *colour_type = 3;
+         *bit_depth = 1;
+         return 1;
+      case 3:
+         *colour_type = 4;
+         *bit_depth = 8;
+         return 1;
+      case 4:
+         *colour_type = 6;
+         *bit_depth = 8;
+         return 1;
+      default:
+         return 0;
+   }
+}
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static unsigned int
+sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
+    png_uint_32 x, unsigned int sample_index)
+{
+   png_uint_32 bit_index, result;
+   /* Find a sample index for the desired sample: */
+   x *= bit_depth;
+   bit_index = x;
+   if ((colour_type & 1) == 0) /* !palette */
+   {
+      if (colour_type & 2)
+         bit_index *= 3;
+      if (colour_type & 4)
+         bit_index += x; /* Alpha channel */
+      /* Multiple channels; select one: */
+      if (colour_type & (2+4))
+         bit_index += sample_index * bit_depth;
+   }
+   /* Return the sample from the row as an integer. */
+   row += bit_index >> 3;
+   result = *row;
+   if (bit_depth == 8)
+      return result;
+   else if (bit_depth > 8)
+      return (result << 8) + *++row;
+   /* Less than 8 bits per sample. */
+   bit_index &= 7;
+   return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+/* Copy a single pixel, of a given size, from one buffer to another -
+ * while this is basically bit addressed there is an implicit assumption
+ * that pixels 8 or more bits in size are byte aligned and that pixels
+ * do not otherwise cross byte boundaries.  (This is, so far as I know,
+ * universally true in bitmap computer graphics.  [JCB 20101212])
+ *
+ * NOTE: The to and from buffers may be the same.
+ */
+static void
+pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
+   png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
+{
+   /* Assume we can multiply by 'size' without overflow because we are
+    * just working in a single buffer.
+    */
+   toIndex *= pixelSize;
+   fromIndex *= pixelSize;
+   if (pixelSize < 8) /* Sub-byte */
+   {
+      /* Mask to select the location of the copied pixel: */
+      unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
+      /* The following read the entire pixels and clears the extra: */
+      unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
+      unsigned int sourceByte = fromBuffer[fromIndex >> 3];
+      /* Don't rely on << or >> supporting '0' here, just in case: */
+      fromIndex &= 7;
+      if (fromIndex > 0) sourceByte <<= fromIndex;
+      if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
+      toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
+   }
+   else /* One or more bytes */
+      memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
+}
+/* Copy a complete row of pixels, taking into account potential partial
+ * bytes at the end.
+ */
+static void
+row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth)
+{
+   memcpy(toBuffer, fromBuffer, bitWidth >> 3);
+   if ((bitWidth & 7) != 0)
+   {
+      unsigned int mask;
+      toBuffer += bitWidth >> 3;
+      fromBuffer += bitWidth >> 3;
+      /* The remaining bits are in the top of the byte, the mask is the bits to
+       * retain.
+       */
+      mask = 0xff >> (bitWidth & 7);
+      *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
+   }
+}
+/* Compare pixels - they are assumed to start at the first byte in the
+ * given buffers.
+ */
+static int
+pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
+{
+#if PNG_LIBPNG_VER < 10506
+   if (memcmp(pa, pb, bit_width>>3) == 0)
+   {
+      png_uint_32 p;
+      if ((bit_width & 7) == 0) return 0;
+      /* Ok, any differences? */
+      p = pa[bit_width >> 3];
+      p ^= pb[bit_width >> 3];
+      if (p == 0) return 0;
+      /* There are, but they may not be significant, remove the bits
+       * after the end (the low order bits in PNG.)
+       */
+      bit_width &= 7;
+      p >>= 8-bit_width;
+      if (p == 0) return 0;
+   }
+#else
+   /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
+    * bits too:
+    */
+   if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
+      return 0;
+#endif
+   /* Return the index of the changed byte. */
+   {
+      png_uint_32 where = 0;
+      while (pa[where] == pb[where]) ++where;
+      return 1+where;
+   }
+}
+/*************************** BASIC PNG FILE WRITING ***************************/
+/* A png_store takes data from the sequential writer or provides data
+ * to the sequential reader.  It can also store the result of a PNG
+ * write for later retrieval.
+ */
+#define STORE_BUFFER_SIZE 500 /* arbitrary */
+typedef struct png_store_buffer
+{
+   struct png_store_buffer*  prev;    /* NOTE: stored in reverse order */
+   png_byte                  buffer[STORE_BUFFER_SIZE];
+} png_store_buffer;
+#define FILE_NAME_SIZE 64
+typedef struct store_palette_entry /* record of a single palette entry */
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+   png_byte alpha;
+} store_palette_entry, store_palette[256];
+typedef struct png_store_file
+{
+   struct png_store_file*  next;      /* as many as you like... */
+   char                    name[FILE_NAME_SIZE];
+   png_uint_32             id;        /* must be correct (see FILEID) */
+   png_size_t              datacount; /* In this (the last) buffer */
+   png_store_buffer        data;      /* Last buffer in file */
+   int                     npalette;  /* Number of entries in palette */
+   store_palette_entry*    palette;   /* May be NULL */
+} png_store_file;
+/* The following is a pool of memory allocated by a single libpng read or write
+ * operation.
+ */
+typedef struct store_pool
+{
+   struct png_store    *store;   /* Back pointer */
+   struct store_memory *list;    /* List of allocated memory */
+   png_byte             mark[4]; /* Before and after data */
+   /* Statistics for this run. */
+   png_alloc_size_t     max;     /* Maximum single allocation */
+   png_alloc_size_t     current; /* Current allocation */
+   png_alloc_size_t     limit;   /* Highest current allocation */
+   png_alloc_size_t     total;   /* Total allocation */
+   /* Overall statistics (retained across successive runs). */
+   png_alloc_size_t     max_max;
+   png_alloc_size_t     max_limit;
+   png_alloc_size_t     max_total;
+} store_pool;
+typedef struct png_store
+{
+   /* For cexcept.h exception handling - simply store one of these;
+    * the context is a self pointer but it may point to a different
+    * png_store (in fact it never does in this program.)
+    */
+   struct exception_context
+                      exception_context;
+   unsigned int       verbose :1;
+   unsigned int       treat_warnings_as_errors :1;
+   unsigned int       expect_error :1;
+   unsigned int       expect_warning :1;
+   unsigned int       saw_warning :1;
+   unsigned int       speed :1;
+   unsigned int       progressive :1; /* use progressive read */
+   unsigned int       validated :1;   /* used as a temporary flag */
+   int                nerrors;
+   int                nwarnings;
+   char               test[128]; /* Name of test */
+   char               error[256];
+   /* Read fields */
+   png_structp        pread;    /* Used to read a saved file */
+   png_infop          piread;
+   png_store_file*    current;  /* Set when reading */
+   png_store_buffer*  next;     /* Set when reading */
+   png_size_t         readpos;  /* Position in *next */
+   png_byte*          image;    /* Buffer for reading interlaced images */
+   png_size_t         cb_image; /* Size of this buffer */
+   png_size_t         cb_row;   /* Row size of the image(s) */
+   png_uint_32        image_h;  /* Number of rows in a single image */
+   store_pool         read_memory_pool;
+   /* Write fields */
+   png_store_file*    saved;
+   png_structp        pwrite;   /* Used when writing a new file */
+   png_infop          piwrite;
+   png_size_t         writepos; /* Position in .new */
+   char               wname[FILE_NAME_SIZE];
+   png_store_buffer   new;      /* The end of the new PNG file being written. */
+   store_pool         write_memory_pool;
+   store_palette_entry* palette;
+   int                  npalette;
+} png_store;
+/* Initialization and cleanup */
+static void
+store_pool_mark(png_bytep mark)
+{
+   static png_uint_32 store_seed[2] = { 0x12345678, 1};
+   make_four_random_bytes(store_seed, mark);
+}
+/* Use this for random 32 bit values; this function makes sure the result is
+ * non-zero.
+ */
+static png_uint_32
+random_32(void)
+{
+   for(;;)
+   {
+      png_byte mark[4];
+      png_uint_32 result;
+      store_pool_mark(mark);
+      result = png_get_uint_32(mark);
+      if (result != 0)
+         return result;
+   }
+}
+static void
+store_pool_init(png_store *ps, store_pool *pool)
+{
+   memset(pool, 0, sizeof *pool);
+   pool->store = ps;
+   pool->list = NULL;
+   pool->max = pool->current = pool->limit = pool->total = 0;
+   pool->max_max = pool->max_limit = pool->max_total = 0;
+   store_pool_mark(pool->mark);
+}
+static void
+store_init(png_store* ps)
+{
+   memset(ps, 0, sizeof *ps);
+   init_exception_context(&ps->exception_context);
+   store_pool_init(ps, &ps->read_memory_pool);
+   store_pool_init(ps, &ps->write_memory_pool);
+   ps->verbose = 0;
+   ps->treat_warnings_as_errors = 0;
+   ps->expect_error = 0;
+   ps->expect_warning = 0;
+   ps->saw_warning = 0;
+   ps->speed = 0;
+   ps->progressive = 0;
+   ps->validated = 0;
+   ps->nerrors = ps->nwarnings = 0;
+   ps->pread = NULL;
+   ps->piread = NULL;
+   ps->saved = ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->image = NULL;
+   ps->cb_image = 0;
+   ps->cb_row = 0;
+   ps->image_h = 0;
+   ps->pwrite = NULL;
+   ps->piwrite = NULL;
+   ps->writepos = 0;
+   ps->new.prev = NULL;
+   ps->palette = NULL;
+   ps->npalette = 0;
+}
+static void
+store_freebuffer(png_store_buffer* psb)
+{
+   if (psb->prev)
+   {
+      store_freebuffer(psb->prev);
+      free(psb->prev);
+      psb->prev = NULL;
+   }
+}
+static void
+store_freenew(png_store *ps)
+{
+   store_freebuffer(&ps->new);
+   ps->writepos = 0;
+   if (ps->palette != NULL)
+   {
+      free(ps->palette);
+      ps->palette = NULL;
+      ps->npalette = 0;
+   }
+}
+static void
+store_storenew(png_store *ps)
+{
+   png_store_buffer *pb;
+   if (ps->writepos != STORE_BUFFER_SIZE)
+      png_error(ps->pwrite, "invalid store call");
+   pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
+   if (pb == NULL)
+      png_error(ps->pwrite, "store new: OOM");
+   *pb = ps->new;
+   ps->new.prev = pb;
+   ps->writepos = 0;
+}
+static void
+store_freefile(png_store_file **ppf)
+{
+   if (*ppf != NULL)
+   {
+      store_freefile(&(*ppf)->next);
+      store_freebuffer(&(*ppf)->data);
+      (*ppf)->datacount = 0;
+      if ((*ppf)->palette != NULL)
+      {
+         free((*ppf)->palette);
+         (*ppf)->palette = NULL;
+         (*ppf)->npalette = 0;
+      }
+      free(*ppf);
+      *ppf = NULL;
+   }
+}
+/* Main interface to file storeage, after writing a new PNG file (see the API
+ * below) call store_storefile to store the result with the given name and id.
+ */
+static void
+store_storefile(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
+   if (pf == NULL)
+      png_error(ps->pwrite, "storefile: OOM");
+   safecat(pf->name, sizeof pf->name, 0, ps->wname);
+   pf->id = id;
+   pf->data = ps->new;
+   pf->datacount = ps->writepos;
+   ps->new.prev = NULL;
+   ps->writepos = 0;
+   pf->palette = ps->palette;
+   pf->npalette = ps->npalette;
+   ps->palette = 0;
+   ps->npalette = 0;
+   /* And save it. */
+   pf->next = ps->saved;
+   ps->saved = pf;
+}
+/* Generate an error message (in the given buffer) */
+static size_t
+store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
+   size_t pos, PNG_CONST char *msg)
+{
+   if (pp != NULL && pp == ps->pread)
+   {
+      /* Reading a file */
+      pos = safecat(buffer, bufsize, pos, "read: ");
+      if (ps->current != NULL)
+      {
+         pos = safecat(buffer, bufsize, pos, ps->current->name);
+         pos = safecat(buffer, bufsize, pos, sep);
+      }
+   }
+   else if (pp != NULL && pp == ps->pwrite)
+   {
+      /* Writing a file */
+      pos = safecat(buffer, bufsize, pos, "write: ");
+      pos = safecat(buffer, bufsize, pos, ps->wname);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+   else
+   {
+      /* Neither reading nor writing (or a memory error in struct delete) */
+      pos = safecat(buffer, bufsize, pos, "pngvalid: ");
+   }
+   if (ps->test[0] != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, ps->test);
+      pos = safecat(buffer, bufsize, pos, sep);
+   }
+   pos = safecat(buffer, bufsize, pos, msg);
+   return pos;
+}
+/* Verbose output to the error stream: */
+static void
+store_verbose(png_store *ps, png_structp pp, png_const_charp prefix,
+   png_const_charp message)
+{
+   char buffer[512];
+   if (prefix)
+      fputs(prefix, stderr);
+   (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
+   fputs(buffer, stderr);
+   fputc('\n', stderr);
+}
+/* Log an error or warning - the relevant count is always incremented. */
+static void
+store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
+{
+   /* The warning is copied to the error buffer if there are no errors and it is
+    * the first warning.  The error is copied to the error buffer if it is the
+    * first error (overwriting any prior warnings).
+    */
+   if (is_error ? (ps->nerrors)++ == 0 :
+       (ps->nwarnings)++ == 0 && ps->nerrors == 0)
+      store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
+   if (ps->verbose)
+      store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
+}
+/* Internal error function, called with a png_store but no libpng stuff. */
+static void
+internal_error(png_store *ps, png_const_charp message)
+{
+   store_log(ps, NULL, message, 1 /* error */);
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+/* Functions to use as PNG callbacks. */
+static void
+store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
+{
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+   if (!ps->expect_error)
+      store_log(ps, pp, message, 1 /* error */);
+   /* And finally throw an exception. */
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      Throw ps;
+   }
+}
+static void
+store_warning(png_structp pp, png_const_charp message)
+{
+   png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+   if (!ps->expect_warning)
+      store_log(ps, pp, message, 0 /* warning */);
+   else
+      ps->saw_warning = 1;
+}
+/* These somewhat odd functions are used when reading an image to ensure that
+ * the buffer is big enough, the png_structp is for errors.
+ */
+/* Return a single row from the correct image. */
+static png_bytep
+store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage,
+   png_uint_32 y)
+{
+   png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
+   if (ps->image == NULL)
+      png_error(pp, "no allocated image");
+   if (coffset + ps->cb_row + 3 > ps->cb_image)
+      png_error(pp, "image too small");
+   return ps->image + coffset;
+}
+static void
+store_image_free(png_store *ps, png_structp pp)
+{
+   if (ps->image != NULL)
+   {
+      png_bytep image = ps->image;
+      if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      {
+         if (pp != NULL)
+            png_error(pp, "png_store image overwrite (1)");
+         else
+            store_log(ps, NULL, "png_store image overwrite (2)", 1);
+      }
+      ps->image = NULL;
+      ps->cb_image = 0;
+      --image;
+      free(image);
+   }
+}
+static void
+store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow,
+   png_uint_32 cRows)
+{
+   png_size_t cb = nImages * cRows * (cbRow + 5);
+   if (ps->cb_image < cb)
+   {
+      png_bytep image;
+      store_image_free(ps, pp);
+      /* The buffer is deliberately mis-aligned. */
+      image = voidcast(png_bytep, malloc(cb+2));
+      if (image == NULL)
+      {
+         /* Called from the startup - ignore the error for the moment. */
+         if (pp == NULL)
+            return;
+         png_error(pp, "OOM allocating image buffer");
+      }
+      /* These magic tags are used to detect overwrites above. */
+      ++image;
+      image[-1] = 0xed;
+      image[cb] = 0xfe;
+      ps->image = image;
+      ps->cb_image = cb;
+   }
+   /* We have an adequate sized image; lay out the rows.  There are 2 bytes at
+    * the start and three at the end of each (this ensures that the row
+    * alignment starts out odd - 2+1 and changes for larger images on each row.)
+    */
+   ps->cb_row = cbRow;
+   ps->image_h = cRows;
+   /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
+    * This deliberately doesn't match the bits in the size test image which are
+    * outside the image; these are set to 0xff (all 1).  To make the row
+    * comparison work in the 'size' test case the size rows are pre-initialized
+    * to the same value prior to calling 'standard_row'.
+    */
+   memset(ps->image, 178, cb);
+   /* Then put in the marks. */
+   while (--nImages >= 0)
+   {
+      png_uint_32 y;
+      for (y=0; y<cRows; ++y)
+      {
+         png_bytep row = store_image_row(ps, pp, nImages, y);
+         /* The markers: */
+         row[-2] = 190;
+         row[-1] = 239;
+         row[cbRow] = 222;
+         row[cbRow+1] = 173;
+         row[cbRow+2] = 17;
+      }
+   }
+}
+static void
+store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage)
+{
+   png_const_bytep image = ps->image;
+   if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+      png_error(pp, "image overwrite");
+   else
+   {
+      png_size_t cbRow = ps->cb_row;
+      png_uint_32 rows = ps->image_h;
+      image += iImage * (cbRow+5) * ps->image_h;
+      image += 2; /* skip image first row markers */
+      while (rows-- > 0)
+      {
+         if (image[-2] != 190 || image[-1] != 239)
+            png_error(pp, "row start overwritten");
+         if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
+            image[cbRow+2] != 17)
+            png_error(pp, "row end overwritten");
+         image += cbRow+5;
+      }
+   }
+}
+static void
+store_write(png_structp pp, png_bytep pb, png_size_t st)
+{
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+   if (ps->pwrite != pp)
+      png_error(pp, "store state damaged");
+   while (st > 0)
+   {
+      size_t cb;
+      if (ps->writepos >= STORE_BUFFER_SIZE)
+         store_storenew(ps);
+      cb = st;
+      if (cb > STORE_BUFFER_SIZE - ps->writepos)
+         cb = STORE_BUFFER_SIZE - ps->writepos;
+      memcpy(ps->new.buffer + ps->writepos, pb, cb);
+      pb += cb;
+      st -= cb;
+      ps->writepos += cb;
+   }
+}
+static void
+store_flush(png_structp pp)
+{
+   UNUSED(pp) /*DOES NOTHING*/
+}
+static size_t
+store_read_buffer_size(png_store *ps)
+{
+   /* Return the bytes available for read in the current buffer. */
+   if (ps->next != &ps->current->data)
+      return STORE_BUFFER_SIZE;
+   return ps->current->datacount;
+}
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Return total bytes available for read. */
+static size_t
+store_read_buffer_avail(png_store *ps)
+{
+   if (ps->current != NULL && ps->next != NULL)
+   {
+      png_store_buffer *next = &ps->current->data;
+      size_t cbAvail = ps->current->datacount;
+      while (next != ps->next && next != NULL)
+      {
+         next = next->prev;
+         cbAvail += STORE_BUFFER_SIZE;
+      }
+      if (next != ps->next)
+         png_error(ps->pread, "buffer read error");
+      if (cbAvail > ps->readpos)
+         return cbAvail - ps->readpos;
+   }
+   return 0;
+}
+#endif
+static int
+store_read_buffer_next(png_store *ps)
+{
+   png_store_buffer *pbOld = ps->next;
+   png_store_buffer *pbNew = &ps->current->data;
+   if (pbOld != pbNew)
+   {
+      while (pbNew != NULL && pbNew->prev != pbOld)
+         pbNew = pbNew->prev;
+      if (pbNew != NULL)
+      {
+         ps->next = pbNew;
+         ps->readpos = 0;
+         return 1;
+      }
+      png_error(ps->pread, "buffer lost");
+   }
+   return 0; /* EOF or error */
+}
+/* Need separate implementation and callback to allow use of the same code
+ * during progressive read, where the io_ptr is set internally by libpng.
+ */
+static void
+store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
+{
+   if (ps->current == NULL || ps->next == NULL)
+      png_error(ps->pread, "store state damaged");
+   while (st > 0)
+   {
+      size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
+      if (cbAvail > 0)
+      {
+         if (cbAvail > st) cbAvail = st;
+         memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
+         st -= cbAvail;
+         pb += cbAvail;
+         ps->readpos += cbAvail;
+      }
+      else if (!store_read_buffer_next(ps))
+         png_error(ps->pread, "read beyond end of file");
+   }
+}
+static void
+store_read(png_structp pp, png_bytep pb, png_size_t st)
+{
+   png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+   if (ps == NULL || ps->pread != pp)
+      png_error(pp, "bad store read call");
+   store_read_imp(ps, pb, st);
+}
+static void
+store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
+{
+   /* Notice that a call to store_read will cause this function to fail because
+    * readpos will be set.
+    */
+   if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+   do
+   {
+      if (ps->readpos != 0)
+         png_error(pp, "store_read called during progressive read");
+      png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
+   }
+   while (store_read_buffer_next(ps));
+}
+/* The caller must fill this in: */
+static store_palette_entry *
+store_write_palette(png_store *ps, int npalette)
+{
+   if (ps->pwrite == NULL)
+      store_log(ps, NULL, "attempt to write palette without write stream", 1);
+   if (ps->palette != NULL)
+      png_error(ps->pwrite, "multiple store_write_palette calls");
+   /* This function can only return NULL if called with '0'! */
+   if (npalette > 0)
+   {
+      ps->palette = voidcast(store_palette_entry*, malloc(npalette *
+         sizeof *ps->palette));
+      if (ps->palette == NULL)
+         png_error(ps->pwrite, "store new palette: OOM");
+      ps->npalette = npalette;
+   }
+   return ps->palette;
+}
+static store_palette_entry *
+store_current_palette(png_store *ps, int *npalette)
+{
+   /* This is an internal error (the call has been made outside a read
+    * operation.)
+    */
+   if (ps->current == NULL)
+      store_log(ps, ps->pread, "no current stream for palette", 1);
+   /* The result may be null if there is no palette. */
+   *npalette = ps->current->npalette;
+   return ps->current->palette;
+}
+/***************************** MEMORY MANAGEMENT*** ***************************/
+/* A store_memory is simply the header for an allocated block of memory.  The
+ * pointer returned to libpng is just after the end of the header block, the
+ * allocated memory is followed by a second copy of the 'mark'.
+ */
+typedef struct store_memory
+{
+   store_pool          *pool;    /* Originating pool */
+   struct store_memory *next;    /* Singly linked list */
+   png_alloc_size_t     size;    /* Size of memory allocated */
+   png_byte             mark[4]; /* ID marker */
+} store_memory;
+/* Handle a fatal error in memory allocation.  This calls png_error if the
+ * libpng struct is non-NULL, else it outputs a message and returns.  This means
+ * that a memory problem while libpng is running will abort (png_error) the
+ * handling of particular file while one in cleanup (after the destroy of the
+ * struct has returned) will simply keep going and free (or attempt to free)
+ * all the memory.
+ */
+static void
+store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
+{
+   if (pp != NULL)
+      png_error(pp, msg);
+   /* Else we have to do it ourselves.  png_error eventually calls store_log,
+    * above.  store_log accepts a NULL png_structp - it just changes what gets
+    * output by store_message.
+    */
+   store_log(ps, pp, msg, 1 /* error */);
+}
+static void
+store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
+{
+   /* Note that pp may be NULL (see store_pool_delete below), the caller has
+    * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
+    * pointer (for sure), but the contents may have been trashed.
+    */
+   if (memory->pool != pool)
+      store_pool_error(pool->store, pp, "memory corrupted (pool)");
+   else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
+      store_pool_error(pool->store, pp, "memory corrupted (start)");
+   /* It should be safe to read the size field now. */
+   else
+   {
+      png_alloc_size_t cb = memory->size;
+      if (cb > pool->max)
+         store_pool_error(pool->store, pp, "memory corrupted (size)");
+      else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
+         != 0)
+         store_pool_error(pool->store, pp, "memory corrupted (end)");
+      /* Finally give the library a chance to find problems too: */
+      else
+         {
+         pool->current -= cb;
+         free(memory);
+         }
+   }
+}
+static void
+store_pool_delete(png_store *ps, store_pool *pool)
+{
+   if (pool->list != NULL)
+   {
+      fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
+         pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+      ++ps->nerrors;
+      do
+      {
+         store_memory *next = pool->list;
+         pool->list = next->next;
+         next->next = NULL;
+         fprintf(stderr, "\t%lu bytes @ %p\n",
+             (unsigned long)next->size, (PNG_CONST void*)(next+1));
+         /* The NULL means this will always return, even if the memory is
+          * corrupted.
+          */
+         store_memory_free(NULL, pool, next);
+      }
+      while (pool->list != NULL);
+   }
+   /* And reset the other fields too for the next time. */
+   if (pool->max > pool->max_max) pool->max_max = pool->max;
+   pool->max = 0;
+   if (pool->current != 0) /* unexpected internal error */
+      fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
+         ps->test, pool == &ps->read_memory_pool ? "read" : "write",
+         pool == &ps->read_memory_pool ? (ps->current != NULL ?
+            ps->current->name : "unknown file") : ps->wname);
+   pool->current = 0;
+   if (pool->limit > pool->max_limit)
+      pool->max_limit = pool->limit;
+   pool->limit = 0;
+   if (pool->total > pool->max_total)
+      pool->max_total = pool->total;
+   pool->total = 0;
+   /* Get a new mark too. */
+   store_pool_mark(pool->mark);
+}
+/* The memory callbacks: */
+static png_voidp
+store_malloc(png_structp pp, png_alloc_size_t cb)
+{
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
+      (sizeof pool->mark)));
+   if (new != NULL)
+   {
+      if (cb > pool->max)
+         pool->max = cb;
+      pool->current += cb;
+      if (pool->current > pool->limit)
+         pool->limit = pool->current;
+      pool->total += cb;
+      new->size = cb;
+      memcpy(new->mark, pool->mark, sizeof new->mark);
+      memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
+      new->pool = pool;
+      new->next = pool->list;
+      pool->list = new;
+      ++new;
+   }
+   else
+   {
+      /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
+       * other than to retrieve the allocation pointer!  libpng calls the
+       * store_malloc callback in two basic cases:
+       *
+       * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
+       *    returned.
+       * 2) From png_struct or png_info structure creation; png_malloc is
+       *    to return so cleanup can be performed.
+       *
+       * To handle this store_malloc can log a message, but can't do anything
+       * else.
+       */
+      store_log(pool->store, pp, "out of memory", 1 /* is_error */);
+   }
+   return new;
+}
+static void
+store_free(png_structp pp, png_voidp memory)
+{
+   store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+   store_memory *this = voidcast(store_memory*, memory), **test;
+   /* Because libpng calls store_free with a dummy png_struct when deleting
+    * png_struct or png_info via png_destroy_struct_2 it is necessary to check
+    * the passed in png_structp to ensure it is valid, and not pass it to
+    * png_error if it is not.
+    */
+   if (pp != pool->store->pread && pp != pool->store->pwrite)
+      pp = NULL;
+   /* First check that this 'memory' really is valid memory - it must be in the
+    * pool list.  If it is, use the shared memory_free function to free it.
+    */
+   --this;
+   for (test = &pool->list; *test != this; test = &(*test)->next)
+   {
+      if (*test == NULL)
+      {
+         store_pool_error(pool->store, pp, "bad pointer to free");
+         return;
+      }
+   }
+   /* Unlink this entry, *test == this. */
+   *test = this->next;
+   this->next = NULL;
+   store_memory_free(pp, pool, this);
+}
+/* Setup functions. */
+/* Cleanup when aborting a write or after storing the new file. */
+static void
+store_write_reset(png_store *ps)
+{
+   if (ps->pwrite != NULL)
+   {
+      anon_context(ps);
+      Try
+         png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
+      Catch_anonymous
+      {
+         /* memory corruption: continue. */
+      }
+      ps->pwrite = NULL;
+      ps->piwrite = NULL;
+   }
+   /* And make sure that all the memory has been freed - this will output
+    * spurious errors in the case of memory corruption above, but this is safe.
+    */
+   store_pool_delete(ps, &ps->write_memory_pool);
+   store_freenew(ps);
+}
+/* The following is the main write function, it returns a png_struct and,
+ * optionally, a png_info suitable for writiing a new PNG file.  Use
+ * store_storefile above to record this file after it has been written.  The
+ * returned libpng structures as destroyed by store_write_reset above.
+ */
+static png_structp
+set_store_for_write(png_store *ps, png_infopp ppi,
+   PNG_CONST char * volatile name)
+{
+   anon_context(ps);
+   Try
+   {
+      if (ps->pwrite != NULL)
+         png_error(ps->pwrite, "write store already in use");
+      store_write_reset(ps);
+      safecat(ps->wname, sizeof ps->wname, 0, name);
+      /* Don't do the slow memory checks if doing a speed test. */
+      if (ps->speed)
+         ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+            ps, store_error, store_warning);
+      else
+         ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
+            ps, store_error, store_warning, &ps->write_memory_pool,
+            store_malloc, store_free);
+      png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
+      if (ppi != NULL)
+         *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
+   }
+   Catch_anonymous
+      return NULL;
+   return ps->pwrite;
+}
+/* Cleanup when finished reading (either due to error or in the success case).
+ */
+static void
+store_read_reset(png_store *ps)
+{
+   if (ps->pread != NULL)
+   {
+      anon_context(ps);
+      Try
+         png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
+      Catch_anonymous
+      {
+         /* error already output: continue */
+      }
+      ps->pread = NULL;
+      ps->piread = NULL;
+   }
+   /* Always do this to be safe. */
+   store_pool_delete(ps, &ps->read_memory_pool);
+   ps->current = NULL;
+   ps->next = NULL;
+   ps->readpos = 0;
+   ps->validated = 0;
+}
+static void
+store_read_set(png_store *ps, png_uint_32 id)
+{
+   png_store_file *pf = ps->saved;
+   while (pf != NULL)
+   {
+      if (pf->id == id)
+      {
+         ps->current = pf;
+         ps->next = NULL;
+         store_read_buffer_next(ps);
+         return;
+      }
+      pf = pf->next;
+   }
+      {
+      size_t pos;
+      char msg[FILE_NAME_SIZE+64];
+      pos = standard_name_from_id(msg, sizeof msg, 0, id);
+      pos = safecat(msg, sizeof msg, pos, ": file not found");
+      png_error(ps->pread, msg);
+      }
+}
+/* The main interface for reading a saved file - pass the id number of the file
+ * to retrieve.  Ids must be unique or the earlier file will be hidden.  The API
+ * returns a png_struct and, optionally, a png_info.  Both of these will be
+ * destroyed by store_read_reset above.
+ */
+static png_structp
+set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
+   PNG_CONST char *name)
+{
+   /* Set the name for png_error */
+   safecat(ps->test, sizeof ps->test, 0, name);
+   if (ps->pread != NULL)
+      png_error(ps->pread, "read store already in use");
+   store_read_reset(ps);
+   /* Both the create APIs can return NULL if used in their default mode
+    * (because there is no other way of handling an error because the jmp_buf
+    * by default is stored in png_struct and that has not been allocated!)
+    * However, given that store_error works correctly in these circumstances
+    * we don't ever expect NULL in this program.
+    */
+   if (ps->speed)
+      ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
+          store_error, store_warning);
+   else
+      ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
+          store_error, store_warning, &ps->read_memory_pool, store_malloc,
+          store_free);
+   if (ps->pread == NULL)
+   {
+      struct exception_context *the_exception_context = &ps->exception_context;
+      store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
+         1 /*error*/);
+      Throw ps;
+   }
+   store_read_set(ps, id);
+   if (ppi != NULL)
+      *ppi = ps->piread = png_create_info_struct(ps->pread);
+   return ps->pread;
+}
+/* The overall cleanup of a store simply calls the above then removes all the
+ * saved files.  This does not delete the store itself.
+ */
+static void
+store_delete(png_store *ps)
+{
+   store_write_reset(ps);
+   store_read_reset(ps);
+   store_freefile(&ps->saved);
+   store_image_free(ps, NULL);
+}
+/*********************** PNG FILE MODIFICATION ON READ ************************/
+/* Files may be modified on read.  The following structure contains a complete
+ * png_store together with extra members to handle modification and a special
+ * read callback for libpng.  To use this the 'modifications' field must be set
+ * to a list of png_modification structures that actually perform the
+ * modification, otherwise a png_modifier is functionally equivalent to a
+ * png_store.  There is a special read function, set_modifier_for_read, which
+ * replaces set_store_for_read.
+ */
+typedef enum modifier_state
+{
+   modifier_start,                        /* Initial value */
+   modifier_signature,                    /* Have a signature */
+   modifier_IHDR                          /* Have an IHDR */
+} modifier_state;
+typedef struct CIE_color
+{
+   /* A single CIE tristimulus value, representing the unique response of a
+    * standard observer to a variety of light spectra.  The observer recognizes
+    * all spectra that produce this response as the same color, therefore this
+    * is effectively a description of a color.
+    */
+   double X, Y, Z;
+} CIE_color;
+static double
+chromaticity_x(CIE_color c)
+{
+   return c.X / (c.X + c.Y + c.Z);
+}
+static double
+chromaticity_y(CIE_color c)
+{
+   return c.Y / (c.X + c.Y + c.Z);
+}
+typedef struct color_encoding
+{
+   /* A description of an (R,G,B) encoding of color (as defined above); this
+    * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
+    * (0,0,1) plus an encoding value that is used to encode the linear
+    * components R, G and B to give the actual values R^gamma, G^gamma and
+    * B^gamma that are stored.
+    */
+   double    gamma;            /* Encoding (file) gamma of space */
+   CIE_color red, green, blue; /* End points */
+} color_encoding;
+static CIE_color
+white_point(PNG_CONST color_encoding *encoding)
+{
+   CIE_color white;
+   
+   white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
+   white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
+   white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
+   return white;
+}
+static void
+normalize_color_encoding(color_encoding *encoding)
+{
+   PNG_CONST double whiteY = encoding->red.Y + encoding->green.Y +
+      encoding->blue.Y;
+   if (whiteY != 1)
+   {
+      encoding->red.X /= whiteY;
+      encoding->red.Y /= whiteY;
+      encoding->red.Z /= whiteY;
+      encoding->green.X /= whiteY;
+      encoding->green.Y /= whiteY;
+      encoding->green.Z /= whiteY;
+      encoding->blue.X /= whiteY;
+      encoding->blue.Y /= whiteY;
+      encoding->blue.Z /= whiteY;
+   }
+}
+static size_t
+safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
+   PNG_CONST color_encoding *e, double encoding_gamma)
+{
+   if (e != 0)
+   {
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, "(");
+      pos = safecat(buffer, bufsize, pos, "R(");
+      pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),G(");
+      pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
+      pos = safecat(buffer, bufsize, pos, "),B(");
+      pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
+      pos = safecat(buffer, bufsize, pos, ",");
+      pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
+      pos = safecat(buffer, bufsize, pos, ")");
+      if (encoding_gamma != 0)
+         pos = safecat(buffer, bufsize, pos, ")");
+   }
+   if (encoding_gamma != 0)
+   {
+      pos = safecat(buffer, bufsize, pos, "^");
+      pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
+   }
+   return pos;
+}
+typedef struct png_modifier
+{
+   png_store               this;             /* I am a png_store */
+   struct png_modification *modifications;   /* Changes to make */
+   modifier_state           state;           /* My state */
+   /* Information from IHDR: */
+   png_byte                 bit_depth;       /* From IHDR */
+   png_byte                 colour_type;     /* From IHDR */
+   /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
+    * other chunks to be inserted.
+    */
+   png_uint_32              pending_len;
+   png_uint_32              pending_chunk;
+   /* Test values */
+   double                   *gammas;
+   unsigned int              ngammas;
+   unsigned int              ngamma_tests;     /* Number of gamma tests to run*/
+   double                    current_gamma;    /* 0 if not set */
+   PNG_CONST color_encoding *encodings;
+   unsigned int              nencodings;
+   PNG_CONST color_encoding *current_encoding; /* If an encoding has been set */
+   unsigned int              encoding_counter; /* For iteration */
+   int                       encoding_ignored; /* Something overwrote it */
+   /* Control variables used to iterate through possible encodings, the
+    * following must be set to 0 and tested by the function that uses the
+    * png_modifier because the modifier only sets it to 1 (true.)
+    */
+   unsigned int              repeat :1;   /* Repeat this transform test. */
+   unsigned int              test_uses_encoding :1;
+   /* Lowest sbit to test (libpng fails for sbit < 8) */
+   png_byte                 sbitlow;
+   /* Error control - these are the limits on errors accepted by the gamma tests
+    * below.
+    */
+   double                   maxout8;  /* Maximum output value error */
+   double                   maxabs8;  /* Absolute sample error 0..1 */
+   double                   maxcalc8; /* Absolute sample error 0..1 */
+   double                   maxpc8;   /* Percentage sample error 0..100% */
+   double                   maxout16; /* Maximum output value error */
+   double                   maxabs16; /* Absolute sample error 0..1 */
+   double                   maxcalc16;/* Absolute sample error 0..1 */
+   double                   maxpc16;  /* Percentage sample error 0..100% */
+   /* This is set by transforms that need to allow a higher limit, it is an
+    * internal check on pngvalid to ensure that the calculated error limits are
+    * not ridiculous; without this it is too easy to make a mistake in pngvalid
+    * that allows any value through.
+    */
+   double                   limit;    /* limit on error values, normally 4E-3 */
+   /* Log limits - values above this are logged, but not necessarily
+    * warned.
+    */
+   double                   log8;     /* Absolute error in 8 bits to log */
+   double                   log16;    /* Absolute error in 16 bits to log */
+   /* Logged 8 and 16 bit errors ('output' values): */
+   double                   error_gray_2;
+   double                   error_gray_4;
+   double                   error_gray_8;
+   double                   error_gray_16;
+   double                   error_color_8;
+   double                   error_color_16;
+   double                   error_indexed;
+   /* Flags: */
+   /* Whether to call png_read_update_info, not png_read_start_image, and how
+    * many times to call it.
+    */
+   int                      use_update_info;
+   /* Whether or not to interlace. */
+   int                      interlace_type :9; /* int, but must store '1' */
+   /* Run the standard tests? */
+   unsigned int             test_standard :1;
+   /* Run the odd-sized image and interlace read/write tests? */
+   unsigned int             test_size :1;
+   /* Run tests on reading with a combiniation of transforms, */
+   unsigned int             test_transform :1;
+   /* When to use the use_input_precision option: */
+   unsigned int             use_input_precision :1;
+   unsigned int             use_input_precision_sbit :1;
+   unsigned int             use_input_precision_16to8 :1;
+   /* If set assume that the calculation bit depth is set by the input
+    * precision, not the output precision.
+    */
+   unsigned int             calculations_use_input_precision :1;
+   /* If set assume that the calculations are done in 16 bits even if both input
+    * and output are 8 bit or less.
+    */
+   unsigned int             assume_16_bit_calculations :1;
+   /* Which gamma tests to run: */
+   unsigned int             test_gamma_threshold :1;
+   unsigned int             test_gamma_transform :1; /* main tests */
+   unsigned int             test_gamma_sbit :1;
+   unsigned int             test_gamma_scale16 :1;
+   unsigned int             test_gamma_background :1;
+   unsigned int             test_gamma_alpha_mode :1;
+   unsigned int             test_gamma_expand16 :1;
+   unsigned int             test_exhaustive :1;
+   unsigned int             log :1;   /* Log max error */
+   /* Buffer information, the buffer size limits the size of the chunks that can
+    * be modified - they must fit (including header and CRC) into the buffer!
+    */
+   size_t                   flush;           /* Count of bytes to flush */
+   size_t                   buffer_count;    /* Bytes in buffer */
+   size_t                   buffer_position; /* Position in buffer */
+   png_byte                 buffer[1024];
+} png_modifier;
+/* This returns true if the test should be stopped now because it has already
+ * failed and it is running silently.
+ */
+static int fail(png_modifier *pm)
+{
+   return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
+       (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
+}
+static void
+modifier_init(png_modifier *pm)
+{
+   memset(pm, 0, sizeof *pm);
+   store_init(&pm->this);
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   pm->sbitlow = 1U;
+   pm->ngammas = 0;
+   pm->ngamma_tests = 0;
+   pm->gammas = 0;
+   pm->current_gamma = 0;
+   pm->encodings = 0;
+   pm->nencodings = 0;
+   pm->current_encoding = 0;
+   pm->encoding_counter = 0;
+   pm->encoding_ignored = 0;
+   pm->repeat = 0;
+   pm->test_uses_encoding = 0;
+   pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
+   pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
+   pm->limit = 4E-3;
+   pm->log8 = pm->log16 = 0; /* Means 'off' */
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+   pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
+   pm->error_indexed = 0;
+   pm->use_update_info = 0;
+   pm->interlace_type = PNG_INTERLACE_NONE;
+   pm->test_standard = 0;
+   pm->test_size = 0;
+   pm->test_transform = 0;
+   pm->use_input_precision = 0;
+   pm->use_input_precision_sbit = 0;
+   pm->use_input_precision_16to8 = 0;
+   pm->calculations_use_input_precision = 0;
+   pm->test_gamma_threshold = 0;
+   pm->test_gamma_transform = 0;
+   pm->test_gamma_sbit = 0;
+   pm->test_gamma_scale16 = 0;
+   pm->test_gamma_background = 0;
+   pm->test_gamma_alpha_mode = 0;
+   pm->test_gamma_expand16 = 0;
+   pm->test_exhaustive = 0;
+   pm->log = 0;
+   /* Rely on the memset for all the other fields - there are no pointers */
+}
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* If pm->calculations_use_input_precision is set then operations will happen
+ * with only 8 bit precision unless both the input and output bit depth are 16.
+ *
+ * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
+ * bit precision.  This only affects those of the following limits that pertain
+ * to a calculation - not a digitization operation - unless the following API is
+ * called directly.
+ */
+static double digitize(PNG_CONST png_modifier *pm, double value,
+   int sample_depth, int do_round)
+{
+   /* 'value' is in the range 0 to 1, the result is the same value rounded to a
+    * multiple of the digitization factor - 8 or 16 bits depending on both the
+    * sample depth and the 'assume' setting.  Digitization is normally by
+    * rounding and 'do_round' should be 1, if it is 0 the digitized value will
+    * be truncated.
+    */
+   PNG_CONST unsigned int digitization_factor =
+      (pm->assume_16_bit_calculations || sample_depth == 16) ? 65535 : 255;
+   /* Limiting the range is done as a convenience to the caller - it's easier to
+    * do it once here than every time at the call site.
+    */
+   if (value <= 0)
+      value = 0;
+   else if (value >= 1)
+      value = 1;
+   value *= digitization_factor;
+   if (do_round) value += .5;
+   return floor(value)/digitization_factor;
+}
+static double abserr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Absolute error permitted in linear values - affected by the bit depth of
+    * the calculations.
+    */
+   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+      !pm->calculations_use_input_precision)))
+      return pm->maxabs16;
+   else
+      return pm->maxabs8;
+}
+static double calcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Error in the linear composition arithmetic - only relevant when
+    * composition actually happens (0 < alpha < 1).
+    */
+   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+      !pm->calculations_use_input_precision)))
+      return pm->maxcalc16;
+   else
+      return pm->maxcalc8;
+}
+static double pcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+   /* Percentage error permitted in the linear values.  Note that the specified
+    * value is a percentage but this routine returns a simple number.
+    */
+   if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+      !pm->calculations_use_input_precision)))
+      return pm->maxpc16 * .01;
+   else
+      return pm->maxpc8 * .01;
+}
+/* Output error - the error in the encoded value.  This is determined by the
+ * digitization of the output so can be +/-0.5 in the actual output value.  In
+ * the expand_16 case with the current code in libpng the expand happens after
+ * all the calculations are done in 8 bit arithmetic, so even though the output
+ * depth is 16 the output error is determined by the 8 bit calculation.
+ *
+ * This limit is not determined by the bit depth of internal calculations.
+ *
+ * The specified parameter does *not* include the base .5 digitization error but
+ * it is added here.
+ */
+static double outerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+   /* There is a serious error in the 2 and 4 bit grayscale transform because
+    * the gamma table value (8 bits) is simply shifted, not rounded, so the
+    * error in 4 bit grayscale gamma is up to the value below.  This is a hack
+    * to allow pngvalid to succeed:
+    *
+    * TODO: fix this in libpng
+    */
+   if (out_depth == 2)
+      return .73182-.5;
+   if (out_depth == 4)
+      return .90644-.5;
+   if (out_depth == 16 && (in_depth == 16 ||
+      !pm->calculations_use_input_precision))
+      return pm->maxout16;
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   else if (out_depth == 16)
+      return pm->maxout8 * 257;
+   else
+      return pm->maxout8;
+}
+/* This does the same thing as the above however it returns the value to log,
+ * rather than raising a warning.  This is useful for debugging to track down
+ * exactly what set of parameters cause high error values.
+ */
+static double outlog(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+   /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
+    * and so must be adjusted for low bit depth grayscale:
+    */
+   if (out_depth <= 8)
+   {
+      if (pm->log8 == 0) /* switched off */
+         return 256;
+      if (out_depth < 8)
+         return pm->log8 / 255 * ((1<<out_depth)-1);
+      return pm->log8;
+   }
+   if (out_depth == 16 && (in_depth == 16 ||
+      !pm->calculations_use_input_precision))
+   {
+      if (pm->log16 == 0)
+         return 65536;
+      return pm->log16;
+   }
+   /* This is the case where the value was calculated at 8-bit precision then
+    * scaled to 16 bits.
+    */
+   if (pm->log8 == 0)
+      return 65536;
+   return pm->log8 * 257;
+}
+/* This complements the above by providing the appropriate quantization for the
+ * final value.  Normally this would just be quantization to an integral value,
+ * but in the 8 bit calculation case it's actually quantization to a multiple of
+ * 257!
+ */
+static int output_quantization_factor(PNG_CONST png_modifier *pm, int in_depth,
+   int out_depth)
+{
+   if (out_depth == 16 && in_depth != 16
+      && pm->calculations_use_input_precision)
+      return 257;
+   else
+      return 1;
+}
+/* One modification structure must be provided for each chunk to be modified (in
+ * fact more than one can be provided if multiple separate changes are desired
+ * for a single chunk.)  Modifications include adding a new chunk when a
+ * suitable chunk does not exist.
+ *
+ * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
+ * or 'added' as appropriate if the modify_fn returns 1 (true).  If the
+ * modify_fn is NULL the chunk is simply removed.
+ */
+typedef struct png_modification
+{
+   struct png_modification *next;
+   png_uint_32              chunk;
+   /* If the following is NULL all matching chunks will be removed: */
+   int                    (*modify_fn)(struct png_modifier *pm,
+                               struct png_modification *me, int add);
+   /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
+    * found and modified (and there is a modify_fn) the modify_fn will be called
+    * to add the chunk before the relevant chunk.
+    */
+   png_uint_32              add;
+   unsigned int             modified :1;     /* Chunk was modified */
+   unsigned int             added    :1;     /* Chunk was added */
+   unsigned int             removed  :1;     /* Chunk was removed */
+} png_modification;
+static void
+modification_reset(png_modification *pmm)
+{
+   if (pmm != NULL)
+   {
+      pmm->modified = 0;
+      pmm->added = 0;
+      pmm->removed = 0;
+      modification_reset(pmm->next);
+   }
+}
+static void
+modification_init(png_modification *pmm)
+{
+   memset(pmm, 0, sizeof *pmm);
+   pmm->next = NULL;
+   pmm->chunk = 0;
+   pmm->modify_fn = NULL;
+   pmm->add = 0;
+   modification_reset(pmm);
+}
+static void
+modifier_current_encoding(PNG_CONST png_modifier *pm, color_encoding *ce)
+{
+   if (pm->current_encoding != 0)
+      *ce = *pm->current_encoding;
+   else
+      memset(ce, 0, sizeof *ce);
+   ce->gamma = pm->current_gamma;
+}
+static size_t
+safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
+   PNG_CONST png_modifier *pm)
+{
+   pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
+      pm->current_gamma);
+   if (pm->encoding_ignored)
+      pos = safecat(buffer, bufsize, pos, "[overridden]");
+   return pos;
+}
+/* Iterate through the usefully testable color encodings.  An encoding is one
+ * of:
+ *
+ * 1) Nothing (no color space, no gamma).
+ * 2) Just a gamma value from the gamma array (including 1.0)
+ * 3) A color space from the encodings array with the corresponding gamma.
+ * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
+ *
+ * The iterator selects these in turn, the randomizer selects one at random,
+ * which is used depends on the setting of the 'test_exhaustive' flag.  Notice
+ * that this function changes the colour space encoding so it must only be
+ * called on completion of the previous test.  This is what 'modifier_reset'
+ * does, below.
+ *
+ * After the function has been called the 'repeat' flag will still be set; the
+ * caller of modifier_reset must reset it at the start of each run of the test!
+ */
+static unsigned int
+modifier_total_encodings(PNG_CONST png_modifier *pm)
+{
+   return 1 +                 /* (1) nothing */
+      pm->ngammas +           /* (2) gamma values to test */
+      pm->nencodings +        /* (3) total number of encodings */
+      /* The following test only works after the first time through the
+       * png_modifier code because 'bit_depth' is set when the IHDR is read.
+       * modifier_reset, below, preserves the setting until after it has called
+       * the iterate function (also below.)
+       *
+       * For this reason do not rely on this function outside a call to
+       * modifier_reset.
+       */
+      ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
+         pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
+}
+static void
+modifier_encoding_iterate(png_modifier *pm)
+{
+   if (!pm->repeat && /* Else something needs the current encoding again. */
+      pm->test_uses_encoding) /* Some transform is encoding dependent */
+   {
+      if (pm->test_exhaustive)
+      {
+         if (++pm->encoding_counter >= modifier_total_encodings(pm))
+            pm->encoding_counter = 0; /* This will stop the repeat */
+      }
+      else
+      {
+         /* Not exhaustive - choose an encoding at random; generate a number in
+          * the range 1..(max-1), so the result is always non-zero:
+          */
+         if (pm->encoding_counter == 0)
+            pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
+         else
+            pm->encoding_counter = 0;
+      }
+      if (pm->encoding_counter > 0)
+         pm->repeat = 1;
+   }
+   else if (!pm->repeat)
+      pm->encoding_counter = 0;
+}
+static void
+modifier_reset(png_modifier *pm)
+{
+   store_read_reset(&pm->this);
+   pm->limit = 4E-3;
+   pm->pending_len = pm->pending_chunk = 0;
+   pm->flush = pm->buffer_count = pm->buffer_position = 0;
+   pm->modifications = NULL;
+   pm->state = modifier_start;
+   modifier_encoding_iterate(pm);
+   /* The following must be set in the next run.  In particular
+    * test_uses_encodings must be set in the _ini function of each transform
+    * that looks at the encodings.  (Not the 'add' function!)
+    */
+   pm->test_uses_encoding = 0;
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0;
+   /* These only become value after IHDR is read: */
+   pm->bit_depth = pm->colour_type = 0;
+}
+/* The following must be called before anything else to get the encoding set up
+ * on the modifier.  In particular it must be called before the transform init
+ * functions are called.
+ */
+static void
+modifier_set_encoding(png_modifier *pm)
+{
+   /* Set the encoding to the one specified by the current encoding counter,
+    * first clear out all the settings - this corresponds to an encoding_counter
+    * of 0.
+    */
+   pm->current_gamma = 0;
+   pm->current_encoding = 0;
+   pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
+   /* Now, if required, set the gamma and encoding fields. */
+   if (pm->encoding_counter > 0)
+   {
+      /* The gammas[] array is an array of screen gammas, not encoding gammas,
+       * so we need the inverse:
+       */
+      if (pm->encoding_counter <= pm->ngammas)
+         pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
+      else
+      {
+         unsigned int i = pm->encoding_counter - pm->ngammas;
+         if (i >= pm->nencodings)
+         {
+            i %= pm->nencodings;
+            pm->current_gamma = 1; /* Linear, only in the 16 bit case */
+         }
+         else
+            pm->current_gamma = pm->encodings[i].gamma;
+         pm->current_encoding = pm->encodings + i;
+      }
+   }
+}
+/* Enquiry functions to find out what is set.  Notice that there is an implicit
+ * assumption below that the first encoding in the list is the one for sRGB.
+ */
+static int
+modifier_color_encoding_is_sRGB(PNG_CONST png_modifier *pm)
+{
+   return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
+      pm->current_encoding->gamma == pm->current_gamma;
+}
+static int
+modifier_color_encoding_is_set(PNG_CONST png_modifier *pm)
+{
+   return pm->current_gamma != 0;
+}
+/* Convenience macros. */
+#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+#define CHUNK_IHDR CHUNK(73,72,68,82)
+#define CHUNK_PLTE CHUNK(80,76,84,69)
+#define CHUNK_IDAT CHUNK(73,68,65,84)
+#define CHUNK_IEND CHUNK(73,69,78,68)
+#define CHUNK_cHRM CHUNK(99,72,82,77)
+#define CHUNK_gAMA CHUNK(103,65,77,65)
+#define CHUNK_sBIT CHUNK(115,66,73,84)
+#define CHUNK_sRGB CHUNK(115,82,71,66)
+/* The guts of modification are performed during a read. */
+static void
+modifier_crc(png_bytep buffer)
+{
+   /* Recalculate the chunk CRC - a complete chunk must be in
+    * the buffer, at the start.
+    */
+   uInt datalen = png_get_uint_32(buffer);
+   uLong crc = crc32(0, buffer+4, datalen+4);
+   /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
+    */
+   png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
+}
+static void
+modifier_setbuffer(png_modifier *pm)
+{
+   modifier_crc(pm->buffer);
+   pm->buffer_count = png_get_uint_32(pm->buffer)+12;
+   pm->buffer_position = 0;
+}
+/* Separate the callback into the actual implementation (which is passed the
+ * png_modifier explicitly) and the callback, which gets the modifier from the
+ * png_struct.
+ */
+static void
+modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
+{
+   while (st > 0)
+   {
+      size_t cb;
+      png_uint_32 len, chunk;
+      png_modification *mod;
+      if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
+      {
+         static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+         case modifier_start:
+            store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+            if (memcmp(pm->buffer, sign, 8) != 0)
+               png_error(pm->this.pread, "invalid PNG file signature");
+            pm->state = modifier_signature;
+            break;
+         case modifier_signature:
+            store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
+            pm->buffer_count = 13+12;
+            pm->buffer_position = 0;
+            if (png_get_uint_32(pm->buffer) != 13 ||
+                png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
+               png_error(pm->this.pread, "invalid IHDR");
+            /* Check the list of modifiers for modifications to the IHDR. */
+            mod = pm->modifications;
+            while (mod != NULL)
+            {
+               if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
+                   (*mod->modify_fn)(pm, mod, 0))
+                  {
+                  mod->modified = 1;
+                  modifier_setbuffer(pm);
+                  }
+               /* Ignore removal or add if IHDR! */
+               mod = mod->next;
+            }
+            /* Cache information from the IHDR (the modified one.) */
+            pm->bit_depth = pm->buffer[8+8];
+            pm->colour_type = pm->buffer[8+8+1];
+            pm->state = modifier_IHDR;
+            pm->flush = 0;
+            break;
+         case modifier_IHDR:
+         default:
+            /* Read a new chunk and process it until we see PLTE, IDAT or
+             * IEND.  'flush' indicates that there is still some data to
+             * output from the preceding chunk.
+             */
+            if ((cb = pm->flush) > 0)
+            {
+               if (cb > st) cb = st;
+               pm->flush -= cb;
+               store_read_imp(&pm->this, pb, cb);
+               pb += cb;
+               st -= cb;
+               if (st == 0) return;
+            }
+            /* No more bytes to flush, read a header, or handle a pending
+             * chunk.
+             */
+            if (pm->pending_chunk != 0)
+            {
+               png_save_uint_32(pm->buffer, pm->pending_len);
+               png_save_uint_32(pm->buffer+4, pm->pending_chunk);
+               pm->pending_len = 0;
+               pm->pending_chunk = 0;
+            }
+            else
+               store_read_imp(&pm->this, pm->buffer, 8);
+            pm->buffer_count = 8;
+            pm->buffer_position = 0;
+            /* Check for something to modify or a terminator chunk. */
+            len = png_get_uint_32(pm->buffer);
+            chunk = png_get_uint_32(pm->buffer+4);
+            /* Terminators first, they may have to be delayed for added
+             * chunks
+             */
+            if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
+                chunk == CHUNK_IEND)
+            {
+               mod = pm->modifications;
+               while (mod != NULL)
+               {
+                  if ((mod->add == chunk ||
+                      (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
+                      mod->modify_fn != NULL && !mod->modified && !mod->added)
+                  {
+                     /* Regardless of what the modify function does do not run
+                      * this again.
+                      */
+                     mod->added = 1;
+                     if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
+                     {
+                        /* Reset the CRC on a new chunk */
+                        if (pm->buffer_count > 0)
+                           modifier_setbuffer(pm);
+                        else
+                           {
+                           pm->buffer_position = 0;
+                           mod->removed = 1;
+                           }
+                        /* The buffer has been filled with something (we assume)
+                         * so output this.  Pend the current chunk.
+                         */
+                        pm->pending_len = len;
+                        pm->pending_chunk = chunk;
+                        break; /* out of while */
+                     }
+                  }
+                  mod = mod->next;
+               }
+               /* Don't do any further processing if the buffer was modified -
+                * otherwise the code will end up modifying a chunk that was
+                * just added.
+                */
+               if (mod != NULL)
+                  break; /* out of switch */
+            }
+            /* If we get to here then this chunk may need to be modified.  To
+             * do this it must be less than 1024 bytes in total size, otherwise
+             * it just gets flushed.
+             */
+            if (len+12 <= sizeof pm->buffer)
+            {
+               store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
+                   len+12-pm->buffer_count);
+               pm->buffer_count = len+12;
+               /* Check for a modification, else leave it be. */
+               mod = pm->modifications;
+               while (mod != NULL)
+               {
+                  if (mod->chunk == chunk)
+                  {
+                     if (mod->modify_fn == NULL)
+                     {
+                        /* Remove this chunk */
+                        pm->buffer_count = pm->buffer_position = 0;
+                        mod->removed = 1;
+                        break; /* Terminate the while loop */
+                     }
+                     else if ((*mod->modify_fn)(pm, mod, 0))
+                     {
+                        mod->modified = 1;
+                        /* The chunk may have been removed: */
+                        if (pm->buffer_count == 0)
+                        {
+                           pm->buffer_position = 0;
+                           break;
+                        }
+                        modifier_setbuffer(pm);
+                     }
+                  }
+                  mod = mod->next;
+               }
+            }
+            else
+               pm->flush = len+12 - pm->buffer_count; /* data + crc */
+            /* Take the data from the buffer (if there is any). */
+            break;
+      }
+      /* Here to read from the modifier buffer (not directly from
+       * the store, as in the flush case above.)
+       */
+      cb = pm->buffer_count - pm->buffer_position;
+      if (cb > st)
+         cb = st;
+      memcpy(pb, pm->buffer + pm->buffer_position, cb);
+      st -= cb;
+      pb += cb;
+      pm->buffer_position += cb;
+   }
+}
+/* The callback: */
+static void
+modifier_read(png_structp pp, png_bytep pb, png_size_t st)
+{
+   png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
+   if (pm == NULL || pm->this.pread != pp)
+      png_error(pp, "bad modifier_read call");
+   modifier_read_imp(pm, pb, st);
+}
+/* Like store_progressive_read but the data is getting changed as we go so we
+ * need a local buffer.
+ */
+static void
+modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
+{
+   if (pm->this.pread != pp || pm->this.current == NULL ||
+       pm->this.next == NULL)
+      png_error(pp, "store state damaged (progressive)");
+   /* This is another Horowitz and Hill random noise generator.  In this case
+    * the aim is to stress the progressive reader with truly horrible variable
+    * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+    * is generated.  We could probably just count from 1 to 32767 and get as
+    * good a result.
+    */
+   for (;;)
+   {
+      static png_uint_32 noise = 1;
+      png_size_t cb, cbAvail;
+      png_byte buffer[512];
+      /* Generate 15 more bits of stuff: */
+      noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+      cb = noise & 0x1ff;
+      /* Check that this number of bytes are available (in the current buffer.)
+       * (This doesn't quite work - the modifier might delete a chunk; unlikely
+       * but possible, it doesn't happen at present because the modifier only
+       * adds chunks to standard images.)
+       */
+      cbAvail = store_read_buffer_avail(&pm->this);
+      if (pm->buffer_count > pm->buffer_position)
+         cbAvail += pm->buffer_count - pm->buffer_position;
+      if (cb > cbAvail)
+      {
+         /* Check for EOF: */
+         if (cbAvail == 0)
+            break;
+         cb = cbAvail;
+      }
+      modifier_read_imp(pm, buffer, cb);
+      png_process_data(pp, pi, buffer, cb);
+   }
+   /* Check the invariants at the end (if this fails it's a problem in this
+    * file!)
+    */
+   if (pm->buffer_count > pm->buffer_position ||
+       pm->this.next != &pm->this.current->data ||
+       pm->this.readpos < pm->this.current->datacount)
+      png_error(pp, "progressive read implementation error");
+}
+/* Set up a modifier. */
+static png_structp
+set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
+    PNG_CONST char *name)
+{
+   /* Do this first so that the modifier fields are cleared even if an error
+    * happens allocating the png_struct.  No allocation is done here so no
+    * cleanup is required.
+    */
+   pm->state = modifier_start;
+   pm->bit_depth = 0;
+   pm->colour_type = 255;
+   pm->pending_len = 0;
+   pm->pending_chunk = 0;
+   pm->flush = 0;
+   pm->buffer_count = 0;
+   pm->buffer_position = 0;
+   return set_store_for_read(&pm->this, ppi, id, name);
+}
+/******************************** MODIFICATIONS *******************************/
+/* Standard modifications to add chunks.  These do not require the _SUPPORTED
+ * macros because the chunks can be there regardless of whether this specific
+ * libpng supports them.
+ */
+typedef struct gama_modification
+{
+   png_modification this;
+   png_fixed_point  gamma;
+} gama_modification;
+static int
+gama_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* This simply dumps the given gamma value into the buffer. */
+   png_save_uint_32(pm->buffer, 4);
+   png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
+   png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
+   return 1;
+}
+static void
+gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
+{
+   double g;
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_gAMA;
+   me->this.modify_fn = gama_modify;
+   me->this.add = CHUNK_PLTE;
+   g = fix(gammad);
+   me->gamma = (png_fixed_point)g;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+typedef struct chrm_modification
+{
+   png_modification          this;
+   PNG_CONST color_encoding *encoding;
+   png_fixed_point           wx, wy, rx, ry, gx, gy, bx, by;
+} chrm_modification;
+static int
+chrm_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As with gAMA this just adds the required cHRM chunk to the buffer. */
+   png_save_uint_32(pm->buffer   , 32);
+   png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
+   png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
+   png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
+   png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
+   png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
+   png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
+   png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
+   png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
+   png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
+   return 1;
+}
+static void
+chrm_modification_init(chrm_modification *me, png_modifier *pm,
+   PNG_CONST color_encoding *encoding)
+{
+   CIE_color white = white_point(encoding);
+   /* Original end points: */
+   me->encoding = encoding;
+   /* Chromaticities (in fixed point): */
+   me->wx = fix(chromaticity_x(white));
+   me->wy = fix(chromaticity_y(white));
+   me->rx = fix(chromaticity_x(encoding->red));
+   me->ry = fix(chromaticity_y(encoding->red));
+   me->gx = fix(chromaticity_x(encoding->green));
+   me->gy = fix(chromaticity_y(encoding->green));
+   me->bx = fix(chromaticity_x(encoding->blue));
+   me->by = fix(chromaticity_y(encoding->blue));
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_cHRM;
+   me->this.modify_fn = chrm_modify;
+   me->this.add = CHUNK_PLTE;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+typedef struct srgb_modification
+{
+   png_modification this;
+   png_byte         intent;
+} srgb_modification;
+static int
+srgb_modify(png_modifier *pm, png_modification *me, int add)
+{
+   UNUSED(add)
+   /* As above, ignore add and just make a new chunk */
+   png_save_uint_32(pm->buffer, 1);
+   png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
+   pm->buffer[8] = ((srgb_modification*)me)->intent;
+   return 1;
+}
+static void
+srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+   if (intent <= 3) /* if valid, else *delete* sRGB chunks */
+   {
+      me->this.modify_fn = srgb_modify;
+      me->this.add = CHUNK_PLTE;
+      me->intent = intent;
+   }
+   else
+   {
+      me->this.modify_fn = 0;
+      me->this.add = 0;
+      me->intent = 0;
+   }
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+typedef struct sbit_modification
+{
+   png_modification this;
+   png_byte         sbit;
+} sbit_modification;
+static int
+sbit_modify(png_modifier *pm, png_modification *me, int add)
+{
+   png_byte sbit = ((sbit_modification*)me)->sbit;
+   if (pm->bit_depth > sbit)
+   {
+      int cb = 0;
+      switch (pm->colour_type)
+      {
+         case 0:
+            cb = 1;
+            break;
+         case 2:
+         case 3:
+            cb = 3;
+            break;
+         case 4:
+            cb = 2;
+            break;
+         case 6:
+            cb = 4;
+            break;
+         default:
+            png_error(pm->this.pread,
+               "unexpected colour type in sBIT modification");
+      }
+      png_save_uint_32(pm->buffer, cb);
+      png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
+      while (cb > 0)
+         (pm->buffer+8)[--cb] = sbit;
+      return 1;
+   }
+   else if (!add)
+   {
+      /* Remove the sBIT chunk */
+      pm->buffer_count = pm->buffer_position = 0;
+      return 1;
+   }
+   else
+      return 0; /* do nothing */
+}
+static void
+sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
+{
+   modification_init(&me->this);
+   me->this.chunk = CHUNK_sBIT;
+   me->this.modify_fn = sbit_modify;
+   me->this.add = CHUNK_PLTE;
+   me->sbit = sbit;
+   me->this.next = pm->modifications;
+   pm->modifications = &me->this;
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+/***************************** STANDARD PNG FILES *****************************/
+/* Standard files - write and save standard files. */
+/* There are two basic forms of standard images.  Those which attempt to have
+ * all the possible pixel values (not possible for 16bpp images, but a range of
+ * values are produced) and those which have a range of image sizes.  The former
+ * are used for testing transforms, in particular gamma correction and bit
+ * reduction and increase.  The latter are reserved for testing the behavior of
+ * libpng with respect to 'odd' image sizes - particularly small images where
+ * rows become 1 byte and interlace passes disappear.
+ *
+ * The first, most useful, set are the 'transform' images, the second set of
+ * small images are the 'size' images.
+ *
+ * The transform files are constructed with rows which fit into a 1024 byte row
+ * buffer.  This makes allocation easier below.  Further regardless of the file
+ * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
+ *
+ * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
+ * and with an ID derived from the colour type, bit depth and interlace type
+ * as above (FILEID).  The width (128) and height (variable) are not stored in
+ * the FILEID - instead the fields are set to 0, indicating a transform file.
+ *
+ * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
+ * a maximum width of 16 pixels (for the 64bpp case.)  They also have a maximum
+ * height of 16 rows.  The width and height are stored in the FILEID and, being
+ * non-zero, indicate a size file.
+ *
+ * For palette image (colour type 3) multiple transform images are stored with
+ * the same bit depth to allow testing of more colour combinations -
+ * particularly important for testing the gamma code because libpng uses a
+ * different code path for palette images.  For size images a single palette is
+ * used.
+ */
+/* Make a 'standard' palette.  Because there are only 256 entries in a palette
+ * (maximum) this actually makes a random palette in the hope that enough tests
+ * will catch enough errors.  (Note that the same palette isn't produced every
+ * time for the same test - it depends on what previous tests have been run -
+ * but a given set of arguments to pngvalid will always produce the same palette
+ * at the same test!  This is why pseudo-random number generators are useful for
+ * testing.)
+ *
+ * The store must be open for write when this is called, otherwise an internal
+ * error will occur.  This routine contains its own magic number seed, so the
+ * palettes generated don't change if there are intervening errors (changing the
+ * calls to the store_mark seed.)
+ */
+static store_palette_entry *
+make_standard_palette(png_store* ps, int npalette, int do_tRNS)
+{
+   static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
+   int i = 0;
+   png_byte values[256][4];
+   /* Always put in black and white plus the six primary and secondary colors.
+    */
+   for (; i<8; ++i)
+   {
+      values[i][1] = (i&1) ? 255 : 0;
+      values[i][2] = (i&2) ? 255 : 0;
+      values[i][3] = (i&4) ? 255 : 0;
+   }
+   /* Then add 62 grays (one quarter of the remaining 256 slots). */
+   {
+      int j = 0;
+      png_byte random_bytes[4];
+      png_byte need[256];
+      need[0] = 0; /*got black*/
+      memset(need+1, 1, (sizeof need)-2); /*need these*/
+      need[255] = 0; /*but not white*/
+      while (i<70)
+      {
+         png_byte b;
+         if (j==0)
+         {
+            make_four_random_bytes(palette_seed, random_bytes);
+            j = 4;
+         }
+         b = random_bytes[--j];
+         if (need[b])
+         {
+            values[i][1] = b;
+            values[i][2] = b;
+            values[i++][3] = b;
+         }
+      }
+   }
+   /* Finally add 192 colors at random - don't worry about matches to things we
+    * already have, chance is less than 1/65536.  Don't worry about grays,
+    * chance is the same, so we get a duplicate or extra gray less than 1 time
+    * in 170.
+    */
+   for (; i<256; ++i)
+      make_four_random_bytes(palette_seed, values[i]);
+   /* Fill in the alpha values in the first byte.  Just use all possible values
+    * (0..255) in an apparently random order:
+    */
+   {
+      store_palette_entry *palette;
+      png_byte selector[4];
+      make_four_random_bytes(palette_seed, selector);
+      if (do_tRNS)
+         for (i=0; i<256; ++i)
+            values[i][0] = (png_byte)(i ^ selector[0]);
+      else
+         for (i=0; i<256; ++i)
+            values[i][0] = 255; /* no transparency/tRNS chunk */
+      /* 'values' contains 256 ARGB values, but we only need 'npalette'.
+       * 'npalette' will always be a power of 2: 2, 4, 16 or 256.  In the low
+       * bit depth cases select colors at random, else it is difficult to have
+       * a set of low bit depth palette test with any chance of a reasonable
+       * range of colors.  Do this by randomly permuting values into the low
+       * 'npalette' entries using an XOR mask generated here.  This also
+       * permutes the npalette == 256 case in a potentially useful way (there is
+       * no relationship between palette index and the color value therein!)
+       */
+      palette = store_write_palette(ps, npalette);
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].alpha = values[i ^ selector[1]][0];
+         palette[i].red   = values[i ^ selector[1]][1];
+         palette[i].green = values[i ^ selector[1]][2];
+         palette[i].blue  = values[i ^ selector[1]][3];
+      }
+      return palette;
+   }
+}
+/* Initialize a standard palette on a write stream.  The 'do_tRNS' argument
+ * indicates whether or not to also set the tRNS chunk.
+ */
+static void
+init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
+   int do_tRNS)
+{
+   store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
+   {
+      int i;
+      png_color palette[256];
+      /* Set all entries to detect overread errors. */
+      for (i=0; i<npalette; ++i)
+      {
+         palette[i].red = ppal[i].red;
+         palette[i].green = ppal[i].green;
+         palette[i].blue = ppal[i].blue;
+      }
+      /* Just in case fill in the rest with detectable values: */
+      for (; i<256; ++i)
+         palette[i].red = palette[i].green = palette[i].blue = 42;
+      png_set_PLTE(pp, pi, palette, npalette);
+   }
+   if (do_tRNS)
+   {
+      int i, j;
+      png_byte tRNS[256];
+      /* Set all the entries, but skip trailing opaque entries */
+      for (i=j=0; i<npalette; ++i)
+         if ((tRNS[i] = ppal[i].alpha) < 255)
+            j = i+1;
+      /* Fill in the remainder with a detectable value: */
+      for (; i<256; ++i)
+         tRNS[i] = 24;
+      if (j > 0)
+         png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
+   }
+}
+/* The number of passes is related to the interlace type. There was no libpng
+ * API to determine this prior to 1.5, so we need an inquiry function:
+ */
+static int
+npasses_from_interlace_type(png_structp pp, int interlace_type)
+{
+   switch (interlace_type)
+   {
+   default:
+      png_error(pp, "invalid interlace type");
+   case PNG_INTERLACE_NONE:
+      return 1;
+   case PNG_INTERLACE_ADAM7:
+      return PNG_INTERLACE_ADAM7_PASSES;
+   }
+}
+static unsigned int
+bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (colour_type)
+   {
+      default: png_error(pp, "invalid color type");
+      case 0:  return bit_depth;
+      case 2:  return 3*bit_depth;
+      case 3:  return bit_depth;
+      case 4:  return 2*bit_depth;
+      case 6:  return 4*bit_depth;
+   }
+}
+#define TRANSFORM_WIDTH  128U
+#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
+#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
+#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
+#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
+static size_t
+transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
+}
+/* transform_width(pp, colour_type, bit_depth) current returns the same number
+ * every time, so just use a macro:
+ */
+#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
+static png_uint_32
+transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+      case 2:
+      case 4:
+         return 1;   /* Total of 128 pixels */
+      case 8:
+         return 2;   /* Total of 256 pixels/bytes */
+      case 16:
+         return 512; /* Total of 65536 pixels */
+      case 24:
+      case 32:
+         return 512; /* 65536 pixels */
+      case 48:
+      case 64:
+         return 2048;/* 4 x 65536 pixels. */
+#        define TRANSFORM_HEIGHTMAX 2048
+      default:
+         return 0;   /* Error, will be caught later */
+   }
+}
+/* The following can only be defined here, now we have the definitions
+ * of the transform image sizes.
+ */
+static png_uint_32
+standard_width(png_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = WIDTH_FROM_ID(id);
+   UNUSED(pp)
+   if (width == 0)
+      width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+   return width;
+}
+static png_uint_32
+standard_height(png_structp pp, png_uint_32 id)
+{
+   png_uint_32 height = HEIGHT_FROM_ID(id);
+   if (height == 0)
+      height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+   return height;
+}
+static png_uint_32
+standard_rowsize(png_structp pp, png_uint_32 id)
+{
+   png_uint_32 width = standard_width(pp, id);
+   /* This won't overflow: */
+   width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+   return (width + 7) / 8;
+}
+static void
+transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
+   png_byte colour_type, png_byte bit_depth, png_uint_32 y)
+{
+   png_uint_32 v = y << 7;
+   png_uint_32 i = 0;
+   switch (bit_size(pp, colour_type, bit_depth))
+   {
+      case 1:
+         while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
+         return;
+      case 2:
+         while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
+         return;
+      case 4:
+         while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
+         return;
+      case 8:
+         /* 256 bytes total, 128 bytes in each row set as follows: */
+         while (i<128) buffer[i] = v & 0xff, ++v, ++i;
+         return;
+      case 16:
+         /* Generate all 65536 pixel values in order, which includes the 8 bit
+          * GA case as well as the 16 bit G case.
+          */
+         while (i<128)
+            buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
+         return;
+      case 24:
+         /* 65535 pixels, but rotate the values. */
+         while (i<128)
+         {
+            /* Three bytes per pixel, r, g, b, make b by r^g */
+            buffer[3*i+0] = (v >> 8) & 0xff;
+            buffer[3*i+1] = v & 0xff;
+            buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
+            ++v;
+            ++i;
+         }
+         return;
+      case 32:
+         /* 65535 pixels, r, g, b, a; just replicate */
+         while (i<128)
+         {
+            buffer[4*i+0] = (v >> 8) & 0xff;
+            buffer[4*i+1] = v & 0xff;
+            buffer[4*i+2] = (v >> 8) & 0xff;
+            buffer[4*i+3] = v & 0xff;
+            ++v;
+            ++i;
+         }
+         return;
+      case 48:
+         /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
+          * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
+          */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[6*i+0] = (t >> 8) & 0xff;
+            buffer[6*i+1] = t & 0xff;
+            t *= 257;
+            buffer[6*i+2] = (t >> 8) & 0xff;
+            buffer[6*i+3] = t & 0xff;
+            t *= 17;
+            buffer[6*i+4] = (t >> 8) & 0xff;
+            buffer[6*i+5] = t & 0xff;
+            ++i;
+         }
+         return;
+      case 64:
+         /* As above in the 32 bit case. */
+         while (i<128)
+         {
+            png_uint_32 t = v++;
+            buffer[8*i+0] = (t >> 8) & 0xff;
+            buffer[8*i+1] = t & 0xff;
+            buffer[8*i+4] = (t >> 8) & 0xff;
+            buffer[8*i+5] = t & 0xff;
+            t *= 257;
+            buffer[8*i+2] = (t >> 8) & 0xff;
+            buffer[8*i+3] = t & 0xff;
+            buffer[8*i+6] = (t >> 8) & 0xff;
+            buffer[8*i+7] = t & 0xff;
+            ++i;
+         }
+         return;
+      default:
+         break;
+   }
+   png_error(pp, "internal error");
+}
+/* This is just to do the right cast - could be changed to a function to check
+ * 'bd' but there isn't much point.
+ */
+#define DEPTH(bd) ((png_byte)(1U << (bd)))
+/* Make a standardized image given a an image colour type, bit depth and
+ * interlace type.  The standard images have a very restricted range of
+ * rows and heights and are used for testing transforms rather than image
+ * layout details.  See make_size_images below for a way to make images
+ * that test odd sizes along with the libpng interlace handling.
+ */
+static void
+make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
+    png_byte PNG_CONST bit_depth, int palette_number, int interlace_type,
+    png_const_charp name)
+{
+   context(ps, fault);
+   Try
+   {
+      png_infop pi;
+      png_structp pp = set_store_for_write(ps, &pi, name);
+      png_uint_32 h;
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+      h = transform_height(pp, colour_type, bit_depth);
+      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
+         bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "image name"; /* must be writeable */
+         size_t pos;
+         png_text text;
+         char copy[FILE_NAME_SIZE];
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = PNG_TEXT_COMPRESSION_zTXt;
+         text.key = key;
+         /* Yuck: the text must be writable! */
+         pos = safecat(copy, sizeof copy, 0, ps->wname);
+         text.text = copy;
+         text.text_length = pos;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
+      png_write_info(pp, pi);
+      if (png_get_rowbytes(pp, pi) !=
+          transform_rowsize(pp, colour_type, bit_depth))
+         png_error(pp, "row size incorrect");
+      else
+      {
+         /* Somewhat confusingly this must be called *after* png_write_info
+          * because if it is called before, the information in *pp has not been
+          * updated to reflect the interlaced image.
+          */
+         int npasses = png_set_interlace_handling(pp);
+         int pass;
+         if (npasses != npasses_from_interlace_type(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+         for (pass=0; pass<npasses; ++pass)
+         {
+            png_uint_32 y;
+            for (y=0; y<h; ++y)
+            {
+               png_byte buffer[TRANSFORM_ROWMAX];
+               transform_row(pp, buffer, colour_type, bit_depth, y);
+               png_write_row(pp, buffer);
+            }
+         }
+      }
+#ifdef PNG_TEXT_SUPPORTED
+      {
+         static char key[] = "end marker";
+         static char comment[] = "end";
+         png_text text;
+         /* Use a compressed text string to test the correct interaction of text
+          * compression and IDAT compression.
+          */
+         text.compression = PNG_TEXT_COMPRESSION_zTXt;
+         text.key = key;
+         text.text = comment;
+         text.text_length = (sizeof comment)-1;
+         text.itxt_length = 0;
+         text.lang = 0;
+         text.lang_key = 0;
+         png_set_text(pp, pi, &text, 1);
+      }
+#endif
+      png_write_end(pp, pi);
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
+         interlace_type, 0, 0, 0));
+      store_write_reset(ps);
+   }
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+static void
+make_transform_images(png_store *ps)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   int palette_number = 0;
+   /* This is in case of errors. */
+   safecat(ps->test, sizeof ps->test, 0, "make standard images");
+   /* Use next_format to enumerate all the combinations we test, including
+    * generating multiple low bit depth palette images.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number))
+   {
+      int interlace_type;
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+      {
+         char name[FILE_NAME_SIZE];
+         standard_name(name, sizeof name, 0, colour_type, bit_depth,
+            palette_number, interlace_type, 0, 0, 0);
+         make_transform_image(ps, colour_type, bit_depth, palette_number,
+            interlace_type, name);
+      }
+   }
+}
+/* The following two routines use the PNG interlace support macros from
+ * png.h to interlace or deinterlace rows.
+ */
+static void
+interlace_row(png_bytep buffer, png_const_bytep imageRow,
+   unsigned int pixel_size, png_uint_32 w, int pass)
+{
+   png_uint_32 xin, xout, xstep;
+   /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
+    * code is presented this way to make it easier to understand.  In practice
+    * consult the code in the libpng source to see other ways of doing this.
+    */
+   xin = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+   for (xout=0; xin<w; xin+=xstep)
+   {
+      pixel_copy(buffer, xout, imageRow, xin, pixel_size);
+      ++xout;
+   }
+}
+static void
+deinterlace_row(png_bytep buffer, png_const_bytep row,
+   unsigned int pixel_size, png_uint_32 w, int pass)
+{
+   /* The inverse of the above, 'row' is part of row 'y' of the output image,
+    * in 'buffer'.  The image is 'w' wide and this is pass 'pass', distribute
+    * the pixels of row into buffer and return the number written (to allow
+    * this to be checked).
+    */
+   png_uint_32 xin, xout, xstep;
+   xout = PNG_PASS_START_COL(pass);
+   xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+   for (xin=0; xout<w; xout+=xstep)
+   {
+      pixel_copy(buffer, xout, row, xin, pixel_size);
+      ++xin;
+   }
+}
+/* Build a single row for the 'size' test images; this fills in only the
+ * first bit_width bits of the sample row.
+ */
+static void
+size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
+{
+   /* height is in the range 1 to 16, so: */
+   y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
+   /* the following ensures bits are set in small images: */
+   y ^= 0xA5;
+   while (bit_width >= 8)
+      *buffer++ = (png_byte)y++, bit_width -= 8;
+   /* There may be up to 7 remaining bits, these go in the most significant
+    * bits of the byte.
+    */
+   if (bit_width > 0)
+   {
+      png_uint_32 mask = (1U<<(8-bit_width))-1;
+      *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
+   }
+}
+static void
+make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
+    png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
+    png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
+    int PNG_CONST do_interlace)
+{
+   context(ps, fault);
+   Try
+   {
+      png_infop pi;
+      png_structp pp;
+      unsigned int pixel_size;
+      /* Make a name and get an appropriate id for the store: */
+      char name[FILE_NAME_SIZE];
+      PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
+         interlace_type, w, h, do_interlace);
+      standard_name_from_id(name, sizeof name, 0, id);
+      pp = set_store_for_write(ps, &pi, name);
+      /* In the event of a problem return control to the Catch statement below
+       * to do the clean up - it is not possible to 'return' directly from a Try
+       * block.
+       */
+      if (pp == NULL)
+         Throw ps;
+      png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+         PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+      png_write_info(pp, pi);
+      /* Calculate the bit size, divide by 8 to get the byte size - this won't
+       * overflow because we know the w values are all small enough even for
+       * a system where 'unsigned int' is only 16 bits.
+       */
+      pixel_size = bit_size(pp, colour_type, bit_depth);
+      if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
+         png_error(pp, "row size incorrect");
+      else
+      {
+         int npasses = npasses_from_interlace_type(pp, interlace_type);
+         png_uint_32 y;
+         int pass;
+         png_byte image[16][SIZE_ROWMAX];
+         /* To help consistent error detection make the parts of this buffer
+          * that aren't set below all '1':
+          */
+         memset(image, 0xff, sizeof image);
+         if (!do_interlace && npasses != png_set_interlace_handling(pp))
+            png_error(pp, "write: png_set_interlace_handling failed");
+         /* Prepare the whole image first to avoid making it 7 times: */
+         for (y=0; y<h; ++y)
+            size_row(image[y], w * pixel_size, y);
+         for (pass=0; pass<npasses; ++pass)
+         {
+            /* The following two are for checking the macros: */
+            PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
+            /* If do_interlace is set we don't call png_write_row for every
+             * row because some of them are empty.  In fact, for a 1x1 image,
+             * most of them are empty!
+             */
+            for (y=0; y<h; ++y)
+            {
+               png_const_bytep row = image[y];
+               png_byte tempRow[SIZE_ROWMAX];
+               /* If do_interlace *and* the image is interlaced we
+                * need a reduced interlace row; this may be reduced
+                * to empty.
+                */
+               if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
+               {
+                  /* The row must not be written if it doesn't exist, notice
+                   * that there are two conditions here, either the row isn't
+                   * ever in the pass or the row would be but isn't wide
+                   * enough to contribute any pixels.  In fact the wPass test
+                   * can be used to skip the whole y loop in this case.
+                   */
+                  if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
+                  {
+                     /* Set to all 1's for error detection (libpng tends to
+                      * set unset things to 0).
+                      */
+                     memset(tempRow, 0xff, sizeof tempRow);
+                     interlace_row(tempRow, row, pixel_size, w, pass);
+                     row = tempRow;
+                  }
+                  else
+                     continue;
+               }
+               /* Only get to here if the row has some pixels in it. */
+               png_write_row(pp, row);
+            }
+         }
+      }
+      png_write_end(pp, pi);
+      /* And store this under the appropriate id, then clean up. */
+      store_storefile(ps, id);
+      store_write_reset(ps);
+   }
+   Catch(fault)
+   {
+      /* Use the png_store returned by the exception. This may help the compiler
+       * because 'ps' is not used in this branch of the setjmp.  Note that fault
+       * and ps will always be the same value.
+       */
+      store_write_reset(fault);
+   }
+}
+static void
+make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
+    int PNG_CONST bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 width;
+      for (width = 1; width <= 16; ++width)
+      {
+         png_uint_32 height;
+         for (height = 1; height <= 16; ++height)
+         {
+            /* The four combinations of DIY interlace and interlace or not -
+             * no interlace + DIY should be identical to no interlace with
+             * libpng doing it.
+             */
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 0);
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+               width, height, 1);
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 0);
+            make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+               width, height, 1);
+         }
+      }
+   }
+}
+static void
+make_size_images(png_store *ps)
+{
+   /* This is in case of errors. */
+   safecat(ps->test, sizeof ps->test, 0, "make size images");
+   /* Arguments are colour_type, low bit depth, high bit depth
+    */
+   make_size(ps, 0, 0, WRITE_BDHI);
+   make_size(ps, 2, 3, WRITE_BDHI);
+   make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
+   make_size(ps, 4, 3, WRITE_BDHI);
+   make_size(ps, 6, 3, WRITE_BDHI);
+}
+/* Return a row based on image id and 'y' for checking: */
+static void
+standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
+   png_uint_32 y)
+{
+   if (WIDTH_FROM_ID(id) == 0)
+      transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
+   else
+      size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
+         DEPTH_FROM_ID(id)), y);
+}
+/* Tests - individual test cases */
+/* Like 'make_standard' but errors are deliberately introduced into the calls
+ * to ensure that they get detected - it should not be possible to write an
+ * invalid image with libpng!
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+static void
+sBIT0_error_fn(png_structp pp, png_infop pi)
+{
+   /* 0 is invalid... */
+   png_color_8 bad;
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
+   png_set_sBIT(pp, pi, &bad);
+}
+static void
+sBIT_error_fn(png_structp pp, png_infop pi)
+{
+   png_byte bit_depth;
+   png_color_8 bad;
+   if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
+      bit_depth = 8;
+   else
+      bit_depth = png_get_bit_depth(pp, pi);
+   /* Now we know the bit depth we can easily generate an invalid sBIT entry */
+   bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
+      (png_byte)(bit_depth+1);
+   png_set_sBIT(pp, pi, &bad);
+}
+static PNG_CONST struct
+{
+   void          (*fn)(png_structp, png_infop);
+   PNG_CONST char *msg;
+   unsigned int    warning :1; /* the error is a warning... */
+} error_test[] =
+    {
+       /* no warnings makes these errors undetectable. */
+       { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
+       { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
+    };
+static void
+make_error(png_store* volatile psIn, png_byte PNG_CONST colour_type,
+    png_byte bit_depth, int interlace_type, int test, png_const_charp name)
+{
+   png_store * volatile ps = psIn;
+   context(ps, fault);
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+      pp = set_store_for_write(ps, &pi, name);
+      if (pp == NULL)
+         Throw ps;
+      png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
+         transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
+         interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+      if (colour_type == 3) /* palette */
+         init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+      /* Time for a few errors; these are in various optional chunks, the
+       * standard tests test the standard chunks pretty well.
+       */
+#     define exception__prev exception_prev_1
+#     define exception__env exception_env_1
+      Try
+      {
+         /* Expect this to throw: */
+         ps->expect_error = !error_test[test].warning;
+         ps->expect_warning = error_test[test].warning;
+         ps->saw_warning = 0;
+         error_test[test].fn(pp, pi);
+         /* Normally the error is only detected here: */
+         png_write_info(pp, pi);
+         /* And handle the case where it was only a warning: */
+         if (ps->expect_warning && ps->saw_warning)
+            Throw ps;
+         /* If we get here there is a problem, we have success - no error or
+          * no warning - when we shouldn't have success.  Log an error.
+          */
+         store_log(ps, pp, error_test[test].msg, 1 /*error*/);
+      }
+      Catch (fault)
+         ps = fault; /* expected exit, make sure ps is not clobbered */
+#undef exception__prev
+#undef exception__env
+      /* And clear these flags */
+      ps->expect_error = 0;
+      ps->expect_warning = 0;
+      /* Now write the whole image, just to make sure that the detected, or
+       * undetected, errro has not created problems inside libpng.
+       */
+      if (png_get_rowbytes(pp, pi) !=
+          transform_rowsize(pp, colour_type, bit_depth))
+         png_error(pp, "row size incorrect");
+      else
+      {
+         png_uint_32 h = transform_height(pp, colour_type, bit_depth);
+         int npasses = png_set_interlace_handling(pp);
+         int pass;
+         if (npasses != npasses_from_interlace_type(pp, interlace_type))
+            png_error(pp, "write: png_set_interlace_handling failed");
+         for (pass=0; pass<npasses; ++pass)
+         {
+            png_uint_32 y;
+            for (y=0; y<h; ++y)
+            {
+               png_byte buffer[TRANSFORM_ROWMAX];
+               transform_row(pp, buffer, colour_type, bit_depth, y);
+               png_write_row(pp, buffer);
+            }
+         }
+      }
+      png_write_end(pp, pi);
+      /* The following deletes the file that was just written. */
+      store_write_reset(ps);
+   }
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+}
+static int
+make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+    int bdlo, int PNG_CONST bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+      {
+         unsigned int test;
+         char name[FILE_NAME_SIZE];
+         standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
+            interlace_type, 0, 0, 0);
+         for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
+         {
+            make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
+               test, name);
+            if (fail(pm))
+               return 0;
+         }
+      }
+   }
+   return 1; /* keep going */
+}
+#endif
+static void
+perform_error_test(png_modifier *pm)
+{
+#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
+   /* Need to do this here because we just write in this test. */
+   safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
+   if (!make_errors(pm, 0, 0, WRITE_BDHI))
+      return;
+   if (!make_errors(pm, 2, 3, WRITE_BDHI))
+      return;
+   if (!make_errors(pm, 3, 0, 3))
+      return;
+   if (!make_errors(pm, 4, 3, WRITE_BDHI))
+      return;
+   if (!make_errors(pm, 6, 3, WRITE_BDHI))
+      return;
+#else
+   UNUSED(pm)
+#endif
+}
+/* This is just to validate the internal PNG formatting code - if this fails
+ * then the warning messages the library outputs will probably be garbage.
+ */
+static void
+perform_formatting_test(png_store *volatile ps)
+{
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+   /* The handle into the formatting code is the RFC1123 support; this test does
+    * nothing if that is compiled out.
+    */
+   context(ps, fault);
+   Try
+   {
+      png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
+      png_const_charp result;
+      png_structp pp;
+      png_time pt;
+      pp = set_store_for_write(ps, NULL, "libpng formatting test");
+      if (pp == NULL)
+         Throw ps;
+      /* Arbitrary settings: */
+      pt.year = 2079;
+      pt.month = 8;
+      pt.day = 29;
+      pt.hour = 13;
+      pt.minute = 53;
+      pt.second = 60; /* a leap second */
+      result = png_convert_to_rfc1123(pp, &pt);
+      if (result == NULL)
+         png_error(pp, "png_convert_to_rfc1123 failed");
+      if (strcmp(result, correct) != 0)
+      {
+         size_t pos = 0;
+         char msg[128];
+         pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
+         pos = safecat(msg, sizeof msg, pos, correct);
+         pos = safecat(msg, sizeof msg, pos, ") returned: '");
+         pos = safecat(msg, sizeof msg, pos, result);
+         pos = safecat(msg, sizeof msg, pos, "'");
+         png_error(pp, msg);
+      }
+      store_write_reset(ps);
+   }
+   Catch(fault)
+   {
+      store_write_reset(fault);
+   }
+#else
+   UNUSED(ps)
+#endif
+}
+/* Because we want to use the same code in both the progressive reader and the
+ * sequential reader it is necessary to deal with the fact that the progressive
+ * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
+ * must contain all the test parameters and all the local variables directly
+ * accessible to the sequential reader implementation.
+ *
+ * The technique adopted is to reinvent part of what Dijkstra termed a
+ * 'display'; an array of pointers to the stack frames of enclosing functions so
+ * that a nested function definition can access the local (C auto) variables of
+ * the functions that contain its definition.  In fact C provides the first
+ * pointer (the local variables - the stack frame pointer) and the last (the
+ * global variables - the BCPL global vector typically implemented as global
+ * addresses), this code requires one more pointer to make the display - the
+ * local variables (and function call parameters) of the function that actually
+ * invokes either the progressive or sequential reader.
+ *
+ * Perhaps confusingly this technique is confounded with classes - the
+ * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
+ * A gamma_display is a standard_display, taking advantage of the ANSI-C
+ * requirement that the pointer to the first member of a structure must be the
+ * same as the pointer to the structure.  This allows us to reuse standard_
+ * functions in the gamma test code; something that could not be done with
+ * nested functions!
+ */
+typedef struct standard_display
+{
+   png_store*  ps;             /* Test parameters (passed to the function) */
+   png_byte    colour_type;
+   png_byte    bit_depth;
+   png_byte    red_sBIT;       /* Input data sBIT values. */
+   png_byte    green_sBIT;
+   png_byte    blue_sBIT;
+   png_byte    alpha_sBIT;
+   int         interlace_type;
+   png_uint_32 id;             /* Calculated file ID */
+   png_uint_32 w;              /* Width of image */
+   png_uint_32 h;              /* Height of image */
+   int         npasses;        /* Number of interlaced passes */
+   png_uint_32 pixel_size;     /* Width of one pixel in bits */
+   png_uint_32 bit_width;      /* Width of output row in bits */
+   size_t      cbRow;          /* Bytes in a row of the output image */
+   int         do_interlace;   /* Do interlacing internally */
+   int         is_transparent; /* Transparency information was present. */
+   int         speed;          /* Doing a speed test */
+   int         use_update_info;/* Call update_info, not start_image */
+   struct
+   {
+      png_uint_16 red;
+      png_uint_16 green;
+      png_uint_16 blue;
+   }           transparent;    /* The transparent color, if set. */
+   int         npalette;       /* Number of entries in the palette. */
+   store_palette
+               palette;
+} standard_display;
+static void
+standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
+   int do_interlace, int use_update_info)
+{
+   memset(dp, 0, sizeof *dp);
+   dp->ps = ps;
+   dp->colour_type = COL_FROM_ID(id);
+   dp->bit_depth = DEPTH_FROM_ID(id);
+   if (dp->bit_depth < 1 || dp->bit_depth > 16)
+      internal_error(ps, "internal: bad bit depth");
+   if (dp->colour_type == 3)
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
+   else
+      dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
+         dp->bit_depth;
+   dp->interlace_type = INTERLACE_FROM_ID(id);
+   dp->id = id;
+   /* All the rest are filled in after the read_info: */
+   dp->w = 0;
+   dp->h = 0;
+   dp->npasses = 0;
+   dp->pixel_size = 0;
+   dp->bit_width = 0;
+   dp->cbRow = 0;
+   dp->do_interlace = do_interlace;
+   dp->is_transparent = 0;
+   dp->speed = ps->speed;
+   dp->use_update_info = use_update_info;
+   dp->npalette = 0;
+   /* Preset the transparent color to black: */
+   memset(&dp->transparent, 0, sizeof dp->transparent);
+   /* Preset the palette to full intensity/opaque througout: */
+   memset(dp->palette, 0xff, sizeof dp->palette);
+}
+/* Initialize the palette fields - this must be done later because the palette
+ * comes from the particular png_store_file that is selected.
+ */
+static void
+standard_palette_init(standard_display *dp)
+{
+   store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
+   /* The remaining entries remain white/opaque. */
+   if (dp->npalette > 0)
+   {
+      int i = dp->npalette;
+      memcpy(dp->palette, palette, i * sizeof *palette);
+      /* Check for a non-opaque palette entry: */
+      while (--i >= 0)
+         if (palette[i].alpha < 255)
+            break;
+#     ifdef __GNUC__
+         /* GCC can't handle the more obviously optimizable version. */
+         if (i >= 0)
+            dp->is_transparent = 1;
+         else
+            dp->is_transparent = 0;
+#     else
+         dp->is_transparent = (i >= 0);
+#     endif
+   }
+}
+/* Utility to read the palette from the PNG file and convert it into
+ * store_palette format.  This returns 1 if there is any transparency in the
+ * palette (it does not check for a transparent colour in the non-palette case.)
+ */
+static int
+read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi)
+{
+   png_colorp pal;
+   png_bytep trans_alpha;
+   int num;
+   pal = 0;
+   *npalette = -1;
+   if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
+   {
+      int i = *npalette;
+      if (i <= 0 || i > 256)
+         png_error(pp, "validate: invalid PLTE count");
+      while (--i >= 0)
+      {
+         palette[i].red = pal[i].red;
+         palette[i].green = pal[i].green;
+         palette[i].blue = pal[i].blue;
+      }
+      /* Mark the remainder of the entries with a flag value (other than
+       * white/opaque which is the flag value stored above.)
+       */
+      memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
+   }
+   else /* !png_get_PLTE */
+   {
+      if (*npalette != (-1))
+         png_error(pp, "validate: invalid PLTE result");
+      /* But there is no palette, so record this: */
+      *npalette = 0;
+      memset(palette, 113, sizeof (store_palette));
+   }
+   trans_alpha = 0;
+   num = 2; /* force error below */
+   if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
+      (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
+      /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
+       * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
+       * so in the above call we get a success, we get a pointer (who knows what
+       * to) and we get num_trans == 0:
+       */
+      !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
+   {
+      int i;
+      /* Any of these are crash-worthy - given the implementation of
+       * png_get_tRNS up to 1.5 an app won't crash if it just checks the
+       * result above and fails to check that the variables it passed have
+       * actually been filled in!  Note that if the app were to pass the
+       * last, png_color_16p, variable too it couldn't rely on this.
+       */
+      if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
+         png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
+      for (i=0; i<num; ++i)
+         palette[i].alpha = trans_alpha[i];
+      for (num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+      for (; i<256; ++i)
+         palette[i].alpha = 33; /* flag value */
+      return 1; /* transparency */
+   }
+   else
+   {
+      /* No palette transparency - just set the alpha channel to opaque. */
+      int i;
+      for (i=0, num=*npalette; i<num; ++i)
+         palette[i].alpha = 255;
+      for (; i<256; ++i)
+         palette[i].alpha = 55; /* flag value */
+      return 0; /* no transparency */
+   }
+}
+/* Utility to validate the palette if it should not have changed (the
+ * non-transform case).
+ */
+static void
+standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi)
+{
+   int npalette;
+   store_palette palette;
+   if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
+      png_error(pp, "validate: palette transparency changed");
+   if (npalette != dp->npalette)
+   {
+      size_t pos = 0;
+      char msg[64];
+      pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
+      pos = safecatn(msg, sizeof msg, pos, dp->npalette);
+      pos = safecat(msg, sizeof msg, pos, " -> ");
+      pos = safecatn(msg, sizeof msg, pos, npalette);
+      png_error(pp, msg);
+   }
+   {
+      int i = npalette; /* npalette is aliased */
+      while (--i >= 0)
+         if (palette[i].red != dp->palette[i].red ||
+            palette[i].green != dp->palette[i].green ||
+            palette[i].blue != dp->palette[i].blue ||
+            palette[i].alpha != dp->palette[i].alpha)
+            png_error(pp, "validate: PLTE or tRNS chunk changed");
+   }
+}
+/* By passing a 'standard_display' the progressive callbacks can be used
+ * directly by the sequential code, the functions suffixed "_imp" are the
+ * implementations, the functions without the suffix are the callbacks.
+ *
+ * The code for the info callback is split into two because this callback calls
+ * png_read_update_info or png_start_read_image and what gets called depends on
+ * whether the info needs updating (we want to test both calls in pngvalid.)
+ */
+static void
+standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
+{
+   if (png_get_bit_depth(pp, pi) != dp->bit_depth)
+      png_error(pp, "validate: bit depth changed");
+   if (png_get_color_type(pp, pi) != dp->colour_type)
+      png_error(pp, "validate: color type changed");
+   if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
+      png_error(pp, "validate: filter type changed");
+   if (png_get_interlace_type(pp, pi) != dp->interlace_type)
+      png_error(pp, "validate: interlacing changed");
+   if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
+      png_error(pp, "validate: compression type changed");
+   dp->w = png_get_image_width(pp, pi);
+   if (dp->w != standard_width(pp, dp->id))
+      png_error(pp, "validate: image width changed");
+   dp->h = png_get_image_height(pp, pi);
+   if (dp->h != standard_height(pp, dp->id))
+      png_error(pp, "validate: image height changed");
+   /* Record (but don't check at present) the input sBIT according to the colour
+    * type information.
+    */
+   {
+      png_color_8p sBIT = 0;
+      if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
+      {
+         int sBIT_invalid = 0;
+         if (sBIT == 0)
+            png_error(pp, "validate: unexpected png_get_sBIT result");
+         if (dp->colour_type & PNG_COLOR_MASK_COLOR)
+         {
+            if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->red_sBIT = sBIT->red;
+            if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->green_sBIT = sBIT->green;
+            if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = sBIT->blue;
+         }
+         else /* !COLOR */
+         {
+            if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
+         }
+         /* All 8 bits in tRNS for a palette image are significant - see the
+          * spec.
+          */
+         if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
+         {
+            if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
+               sBIT_invalid = 1;
+            else
+               dp->alpha_sBIT = sBIT->alpha;
+         }
+         if (sBIT_invalid)
+            png_error(pp, "validate: sBIT value out of range");
+      }
+   }
+   /* Important: this is validating the value *before* any transforms have been
+    * put in place.  It doesn't matter for the standard tests, where there are
+    * no transforms, but it does for other tests where rowbytes may change after
+    * png_read_update_info.
+    */
+   if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
+      png_error(pp, "validate: row size changed");
+   /* Validate the colour type 3 palette (this can be present on other color
+    * types.)
+    */
+   standard_palette_validate(dp, pp, pi);
+   /* In any case always check for a tranparent color (notice that the
+    * colour type 3 case must not give a successful return on the get_tRNS call
+    * with these arguments!)
+    */
+   {
+      png_color_16p trans_color = 0;
+      if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
+      {
+         if (trans_color == 0)
+            png_error(pp, "validate: unexpected png_get_tRNS (color) result");
+         switch (dp->colour_type)
+         {
+         case 0:
+            dp->transparent.red = dp->transparent.green = dp->transparent.blue =
+               trans_color->gray;
+            dp->is_transparent = 1;
+            break;
+         case 2:
+            dp->transparent.red = trans_color->red;
+            dp->transparent.green = trans_color->green;
+            dp->transparent.blue = trans_color->blue;
+            dp->is_transparent = 1;
+            break;
+         case 3:
+            /* Not expected because it should result in the array case
+             * above.
+             */
+            png_error(pp, "validate: unexpected png_get_tRNS result");
+            break;
+         default:
+            png_error(pp, "validate: invalid tRNS chunk with alpha image");
+         }
+      }
+   }
+   /* Read the number of passes - expected to match the value used when
+    * creating the image (interlaced or not).  This has the side effect of
+    * turning on interlace handling (if do_interlace is not set.)
+    */
+   dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
+   if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
+      png_error(pp, "validate: file changed interlace type");
+   /* Caller calls png_read_update_info or png_start_read_image now, then calls
+    * part2.
+    */
+}
+/* This must be called *after* the png_read_update_info call to get the correct
+ * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
+ * image.
+ */
+static void
+standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
+    int nImages)
+{
+   /* Record cbRow now that it can be found. */
+   dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
+      png_get_bit_depth(pp, pi));
+   dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
+   dp->cbRow = png_get_rowbytes(pp, pi);
+   /* Validate the rowbytes here again. */
+   if (dp->cbRow != (dp->bit_width+7)/8)
+      png_error(pp, "bad png_get_rowbytes calculation");
+   /* Then ensure there is enough space for the output image(s). */
+   store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
+}
+static void
+standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
+    int nImages)
+{
+   /* Note that the validation routine has the side effect of turning on
+    * interlace handling in the subsequent code.
+    */
+   standard_info_part1(dp, pp, pi);
+   /* And the info callback has to call this (or png_read_update_info - see
+    * below in the png_modifier code for that variant.
+    */
+   if (dp->use_update_info)
+   {
+      /* For debugging the effect of multiple calls: */
+      int i = dp->use_update_info;
+      while (i-- > 0)
+         png_read_update_info(pp, pi);
+   }
+   else
+      png_start_read_image(pp);
+   /* Validate the height, width and rowbytes plus ensure that sufficient buffer
+    * exists for decoding the image.
+    */
+   standard_info_part2(dp, pp, pi, nImages);
+}
+static void
+standard_info(png_structp pp, png_infop pi)
+{
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+   /* Call with nImages==1 because the progressive reader can only produce one
+    * image.
+    */
+   standard_info_imp(dp, pp, pi, 1 /*only one image*/);
+}
+static void
+progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
+{
+   PNG_CONST standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+   /* When handling interlacing some rows will be absent in each pass, the
+    * callback still gets called, but with a NULL pointer.  This is checked
+    * in the 'else' clause below.  We need our own 'cbRow', but we can't call
+    * png_get_rowbytes because we got no info structure.
+    */
+   if (new_row != NULL)
+   {
+      png_bytep row;
+      /* In the case where the reader doesn't do the interlace it gives
+       * us the y in the sub-image:
+       */
+      if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
+      {
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+         /* Use this opportunity to validate the png 'current' APIs: */
+         if (y != png_get_current_row_number(pp))
+            png_error(pp, "png_get_current_row_number is broken");
+         if (pass != png_get_current_pass_number(pp))
+            png_error(pp, "png_get_current_pass_number is broken");
+#endif
+         y = PNG_ROW_FROM_PASS_ROW(y, pass);
+      }
+      /* Validate this just in case. */
+      if (y >= dp->h)
+         png_error(pp, "invalid y to progressive row callback");
+      row = store_image_row(dp->ps, pp, 0, y);
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+      /* Combine the new row into the old: */
+      if (dp->do_interlace)
+      {
+         if (dp->interlace_type == PNG_INTERLACE_ADAM7)
+            deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
+         else
+            row_copy(row, new_row, dp->pixel_size * dp->w);
+      }
+      else
+         png_progressive_combine_row(pp, row, new_row);
+   } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
+      PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+      PNG_PASS_COLS(dp->w, pass) > 0)
+      png_error(pp, "missing row in progressive de-interlacing");
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+}
+static void
+sequential_row(standard_display *dp, png_structp pp, png_infop pi,
+    PNG_CONST int iImage, PNG_CONST int iDisplay)
+{
+   PNG_CONST int         npasses = dp->npasses;
+   PNG_CONST int         do_interlace = dp->do_interlace &&
+      dp->interlace_type == PNG_INTERLACE_ADAM7;
+   PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
+   PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
+   PNG_CONST png_store*  ps = dp->ps;
+   int pass;
+   for (pass=0; pass<npasses; ++pass)
+   {
+      png_uint_32 y;
+      png_uint_32 wPass = PNG_PASS_COLS(width, pass);
+      for (y=0; y<height; ++y)
+      {
+         if (do_interlace)
+         {
+            /* wPass may be zero or this row may not be in this pass.
+             * png_read_row must not be called in either case.
+             */
+            if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
+            {
+               /* Read the row into a pair of temporary buffers, then do the
+                * merge here into the output rows.
+                */
+               png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
+               /* The following aids (to some extent) error detection - we can
+                * see where png_read_row wrote.  Use opposite values in row and
+                * display to make this easier.  Don't use 0xff (which is used in
+                * the image write code to fill unused bits) or 0 (which is a
+                * likely value to overwrite unused bits with).
+                */
+               memset(row, 0xc5, sizeof row);
+               memset(display, 0x5c, sizeof display);
+               png_read_row(pp, row, display);
+               if (iImage >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iImage, y), row,
+                     dp->pixel_size, dp->w, pass);
+               if (iDisplay >= 0)
+                  deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
+                     dp->pixel_size, dp->w, pass);
+            }
+         }
+         else
+            png_read_row(pp,
+               iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
+               iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
+      }
+   }
+   /* And finish the read operation (only really necessary if the caller wants
+    * to find additional data in png_info from chunks after the last IDAT.)
+    */
+   png_read_end(pp, pi);
+}
+static void
+standard_row_validate(standard_display *dp, png_structp pp,
+   int iImage, int iDisplay, png_uint_32 y)
+{
+   int where;
+   png_byte std[STANDARD_ROWMAX];
+   /* The row must be pre-initialized to the magic number here for the size
+    * tests to pass:
+    */
+   memset(std, 178, sizeof std);
+   standard_row(pp, std, dp->id, y);
+   /* At the end both the 'row' and 'display' arrays should end up identical.
+    * In earlier passes 'row' will be partially filled in, with only the pixels
+    * that have been read so far, but 'display' will have those pixels
+    * replicated to fill the unread pixels while reading an interlaced image.
+#if PNG_LIBPNG_VER < 10506
+    * The side effect inside the libpng sequential reader is that the 'row'
+    * array retains the correct values for unwritten pixels within the row
+    * bytes, while the 'display' array gets bits off the end of the image (in
+    * the last byte) trashed.  Unfortunately in the progressive reader the
+    * row bytes are always trashed, so we always do a pixel_cmp here even though
+    * a memcmp of all cbRow bytes will succeed for the sequential reader.
+#endif
+    */
+   if (iImage >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
+            dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "PNG image row[%d][%d] changed from %.2x to %.2x", y,
+         where-1, std[where-1],
+         store_image_row(dp->ps, pp, iImage, y)[where-1]);
+      png_error(pp, msg);
+   }
+#if PNG_LIBPNG_VER < 10506
+   /* In this case use pixel_cmp because we need to compare a partial
+    * byte at the end of the row if the row is not an exact multiple
+    * of 8 bits wide.  (This is fixed in libpng-1.5.6 and pixel_cmp is
+    * changed to match!)
+    */
+#endif
+   if (iDisplay >= 0 &&
+      (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
+         dp->bit_width)) != 0)
+   {
+      char msg[64];
+      sprintf(msg, "display  row[%d][%d] changed from %.2x to %.2x", y,
+         where-1, std[where-1],
+         store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
+      png_error(pp, msg);
+   }
+}
+static void
+standard_image_validate(standard_display *dp, png_structp pp, int iImage,
+    int iDisplay)
+{
+   png_uint_32 y;
+   if (iImage >= 0)
+      store_image_check(dp->ps, pp, iImage);
+   if (iDisplay >= 0)
+      store_image_check(dp->ps, pp, iDisplay);
+   for (y=0; y<dp->h; ++y)
+      standard_row_validate(dp, pp, iImage, iDisplay, y);
+   /* This avoids false positives if the validation code is never called! */
+   dp->ps->validated = 1;
+}
+static void
+standard_end(png_structp pp, png_infop pi)
+{
+   standard_display *dp = voidcast(standard_display*,
+      png_get_progressive_ptr(pp));
+   UNUSED(pi)
+   /* Validate the image - progressive reading only produces one variant for
+    * interlaced images.
+    */
+   standard_image_validate(dp, pp, 0, -1);
+}
+/* A single test run checking the standard image to ensure it is not damaged. */
+static void
+standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
+   int do_interlace, int use_update_info)
+{
+   standard_display d;
+   context(psIn, fault);
+   /* Set up the display (stack frame) variables from the arguments to the
+    * function and initialize the locals that are filled in later.
+    */
+   standard_display_init(&d, psIn, id, do_interlace, use_update_info);
+   /* Everything is protected by a Try/Catch.  The functions called also
+    * typically have local Try/Catch blocks.
+    */
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+      /* Get a png_struct for reading the image. This will throw an error if it
+       * fails, so we don't need to check the result.
+       */
+      pp = set_store_for_read(d.ps, &pi, d.id,
+         d.do_interlace ?  (d.ps->progressive ?
+            "pngvalid progressive deinterlacer" :
+            "pngvalid sequential deinterlacer") : (d.ps->progressive ?
+               "progressive reader" : "sequential reader"));
+      /* Initialize the palette correctly from the png_store_file. */
+      standard_palette_init(&d);
+      /* Introduce the correct read function. */
+      if (d.ps->progressive)
+      {
+         png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
+            standard_end);
+         /* Now feed data into the reader until we reach the end: */
+         store_progressive_read(d.ps, pp, pi);
+      }
+      else
+      {
+         /* Note that this takes the store, not the display. */
+         png_set_read_fn(pp, d.ps, store_read);
+         /* Check the header values: */
+         png_read_info(pp, pi);
+         /* The code tests both versions of the images that the sequential
+          * reader can produce.
+          */
+         standard_info_imp(&d, pp, pi, 2 /*images*/);
+         /* Need the total bytes in the image below; we can't get to this point
+          * unless the PNG file values have been checked against the expected
+          * values.
+          */
+         {
+            sequential_row(&d, pp, pi, 0, 1);
+            /* After the last pass loop over the rows again to check that the
+             * image is correct.
+             */
+            if (!d.speed)
+               standard_image_validate(&d, pp, 0, 1);
+            else
+               d.ps->validated = 1;
+         }
+      }
+      /* Check for validation. */
+      if (!d.ps->validated)
+         png_error(pp, "image read failed silently");
+      /* Successful completion. */
+   }
+   Catch(fault)
+      d.ps = fault; /* make sure this hasn't been clobbered. */
+   /* In either case clean up the store. */
+   store_read_reset(d.ps);
+}
+static int
+test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+    int bdlo, int PNG_CONST bdhi)
+{
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      int interlace_type;
+      for (interlace_type = PNG_INTERLACE_NONE;
+           interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+      {
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            interlace_type, 0, 0, 0), 0/*do_interlace*/, pm->use_update_info);
+         if (fail(pm))
+            return 0;
+      }
+   }
+   return 1; /* keep going */
+}
+static void
+perform_standard_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_standard(pm, 0, 0, READ_BDHI))
+      return;
+   if (!test_standard(pm, 2, 3, READ_BDHI))
+      return;
+   if (!test_standard(pm, 3, 0, 3))
+      return;
+   if (!test_standard(pm, 4, 3, READ_BDHI))
+      return;
+   if (!test_standard(pm, 6, 3, READ_BDHI))
+      return;
+}
+/********************************** SIZE TESTS ********************************/
+static int
+test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+    int bdlo, int PNG_CONST bdhi)
+{
+   /* Run the tests on each combination.
+    *
+    * NOTE: on my 32 bit x86 each of the following blocks takes
+    * a total of 3.5 seconds if done across every combo of bit depth
+    * width and height.  This is a waste of time in practice, hence the
+    * hinc and winc stuff:
+    */
+   static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
+   static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
+   for (; bdlo <= bdhi; ++bdlo)
+   {
+      png_uint_32 h, w;
+      for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
+      {
+         /* First test all the 'size' images against the sequential
+          * reader using libpng to deinterlace (where required.)  This
+          * validates the write side of libpng.  There are four possibilities
+          * to validate.
+          */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+         /* Now validate the interlaced read side - do_interlace true,
+          * in the progressive case this does actually make a difference
+          * to the code used in the non-interlaced case too.
+          */
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+         standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+            PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
+            pm->use_update_info);
+         if (fail(pm))
+            return 0;
+      }
+   }
+   return 1; /* keep going */
+}
+static void
+perform_size_test(png_modifier *pm)
+{
+   /* Test each colour type over the valid range of bit depths (expressed as
+    * log2(bit_depth) in turn, stop as soon as any error is detected.
+    */
+   if (!test_size(pm, 0, 0, READ_BDHI))
+      return;
+   if (!test_size(pm, 2, 3, READ_BDHI))
+      return;
+   /* For the moment don't do the palette test - it's a waste of time when
+    * compared to the grayscale test.
+    */
+#if 0
+   if (!test_size(pm, 3, 0, 3))
+      return;
+#endif
+   if (!test_size(pm, 4, 3, READ_BDHI))
+      return;
+   if (!test_size(pm, 6, 3, READ_BDHI))
+      return;
+}
+/******************************* TRANSFORM TESTS ******************************/
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* A set of tests to validate libpng image transforms.  The possibilities here
+ * are legion because the transforms can be combined in a combinatorial
+ * fashion.  To deal with this some measure of restraint is required, otherwise
+ * the tests would take forever.
+ */
+typedef struct image_pixel
+{
+   /* A local (pngvalid) representation of a PNG pixel, in all its
+    * various forms.
+    */
+   unsigned int red, green, blue, alpha; /* For non-palette images. */
+   unsigned int palette_index;           /* For a palette image. */
+   png_byte colour_type;                 /* As in the spec. */
+   png_byte bit_depth;                   /* Defines bit size in row */
+   png_byte sample_depth;                /* Scale of samples */
+   int      have_tRNS;                   /* tRNS chunk may need processing */
+   /* For checking the code calculates double precision floating point values
+    * along with an error value, accumulated from the transforms.  Because an
+    * sBIT setting allows larger error bounds (indeed, by the spec, apparently
+    * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
+    * channel is stored.  This sBIT value is folded in to the stored error value
+    * at the end of the application of the transforms to the pixel.
+    */
+   double   redf, greenf, bluef, alphaf;
+   double   rede, greene, bluee, alphae;
+   png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
+} image_pixel;
+/* Shared utility function, see below. */
+static void
+image_pixel_setf(image_pixel *this, unsigned int max)
+{
+   this->redf = this->red / (double)max;
+   this->greenf = this->green / (double)max;
+   this->bluef = this->blue / (double)max;
+   this->alphaf = this->alpha / (double)max;
+   if (this->red < max)
+      this->rede = this->redf * DBL_EPSILON;
+   else
+      this->rede = 0;
+   if (this->green < max)
+      this->greene = this->greenf * DBL_EPSILON;
+   else
+      this->greene = 0;
+   if (this->blue < max)
+      this->bluee = this->bluef * DBL_EPSILON;
+   else
+      this->bluee = 0;
+   if (this->alpha < max)
+      this->alphae = this->alphaf * DBL_EPSILON;
+   else
+      this->alphae = 0;
+}
+/* Initialize the structure for the next pixel - call this before doing any
+ * transforms and call it for each pixel since all the fields may need to be
+ * reset.
+ */
+static void
+image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
+    png_byte bit_depth, png_uint_32 x, store_palette palette)
+{
+   PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
+      PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
+   PNG_CONST unsigned int max = (1U<<sample_depth)-1;
+   /* Initially just set everything to the same number and the alpha to opaque.
+    * Note that this currently assumes a simple palette where entry x has colour
+    * rgb(x,x,x)!
+    */
+   this->palette_index = this->red = this->green = this->blue =
+      sample(row, colour_type, bit_depth, x, 0);
+   this->alpha = max;
+   this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
+      sample_depth;
+   /* Then override as appropriate: */
+   if (colour_type == 3) /* palette */
+   {
+      /* This permits the caller to default to the sample value. */
+      if (palette != 0)
+      {
+         PNG_CONST unsigned int i = this->palette_index;
+         this->red = palette[i].red;
+         this->green = palette[i].green;
+         this->blue = palette[i].blue;
+         this->alpha = palette[i].alpha;
+      }
+   }
+   else /* not palette */
+   {
+      unsigned int i = 0;
+      if (colour_type & 2)
+      {
+         this->green = sample(row, colour_type, bit_depth, x, 1);
+         this->blue = sample(row, colour_type, bit_depth, x, 2);
+         i = 2;
+      }
+      if (colour_type & 4)
+         this->alpha = sample(row, colour_type, bit_depth, x, ++i);
+   }
+   /* Calculate the scaled values, these are simply the values divided by
+    * 'max' and the error is initialized to the double precision epsilon value
+    * from the header file.
+    */
+   image_pixel_setf(this, max);
+   /* Store the input information for use in the transforms - these will
+    * modify the information.
+    */
+   this->colour_type = colour_type;
+   this->bit_depth = bit_depth;
+   this->sample_depth = sample_depth;
+   this->have_tRNS = 0;
+}
+/* Convert a palette image to an rgb image.  This necessarily converts the tRNS
+ * chunk at the same time, because the tRNS will be in palette form.  The way
+ * palette validation works means that the original palette is never updated,
+ * instead the image_pixel value from the row contains the RGB of the
+ * corresponding palette entry and *this* is updated.  Consequently this routine
+ * only needs to change the colour type information.
+ */
+static void
+image_pixel_convert_PLTE(image_pixel *this)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (this->have_tRNS)
+      {
+         this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         this->have_tRNS = 0;
+      }
+      else
+         this->colour_type = PNG_COLOR_TYPE_RGB;
+      /* The bit depth of the row changes at this point too (notice that this is
+       * the row format, not the sample depth, which is separate.)
+       */
+      this->bit_depth = 8;
+   }
+}
+/* Add an alpha channel; this will import the tRNS information because tRNS is
+ * not valid in an alpha image.  The bit depth will invariably be set to at
+ * least 8.  Palette images will be converted to alpha (using the above API).
+ */
+static void
+image_pixel_add_alpha(image_pixel *this, PNG_CONST standard_display *display)
+{
+   if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(this);
+   if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+   {
+      if (this->colour_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (this->bit_depth < 8)
+            this->bit_depth = 8;
+         if (this->have_tRNS)
+         {
+            this->have_tRNS = 0;
+            /* Check the input, original, channel value here against the
+             * original tRNS gray chunk valie.
+             */
+            if (this->red == display->transparent.red)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+         }
+         else
+            this->alphaf = 1;
+         this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+      }
+      else if (this->colour_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (this->have_tRNS)
+         {
+            this->have_tRNS = 0;
+            /* Again, check the exact input values, not the current transformed
+             * value!
+             */
+            if (this->red == display->transparent.red &&
+               this->green == display->transparent.green &&
+               this->blue == display->transparent.blue)
+               this->alphaf = 0;
+            else
+               this->alphaf = 1;
+            this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         }
+      }
+      /* The error in the alpha is zero and the sBIT value comes from the
+       * original sBIT data (actually it will always be the original bit depth).
+       */
+      this->alphae = 0;
+      this->alpha_sBIT = display->alpha_sBIT;
+   }
+}
+struct transform_display;
+typedef struct image_transform
+{
+   /* The name of this transform: a string. */
+   PNG_CONST char *name;
+   /* Each transform can be disabled from the command line: */
+   int enable;
+   /* The global list of transforms; read only. */
+   struct image_transform *PNG_CONST list;
+   /* The global count of the number of times this transform has been set on an
+    * image.
+    */
+   unsigned int global_use;
+   /* The local count of the number of times this transform has been set. */
+   unsigned int local_use;
+   /* The next transform in the list, each transform must call its own next
+    * transform after it has processed the pixel successfully.
+    */
+   PNG_CONST struct image_transform *next;
+   /* A single transform for the image, expressed as a series of function
+    * callbacks and some space for values.
+    *
+    * First a callback to add any required modifications to the png_modifier;
+    * this gets called just before the modifier is set up for read.
+    */
+   void (*ini)(PNG_CONST struct image_transform *this,
+      struct transform_display *that);
+   /* And a callback to set the transform on the current png_read_struct:
+    */
+   void (*set)(PNG_CONST struct image_transform *this,
+      struct transform_display *that, png_structp pp, png_infop pi);
+   /* Then a transform that takes an input pixel in one PNG format or another
+    * and modifies it by a pngvalid implementation of the transform (thus
+    * duplicating the libpng intent without, we hope, duplicating the bugs
+    * in the libpng implementation!)  The png_structp is solely to allow error
+    * reporting via png_error and png_warning.
+    */
+   void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
+      png_structp pp, PNG_CONST struct transform_display *display);
+   /* Add this transform to the list and return true if the transform is
+    * meaningful for this colour type and bit depth - if false then the
+    * transform should have no effect on the image so there's not a lot of
+    * point running it.
+    */
+   int (*add)(struct image_transform *this,
+      PNG_CONST struct image_transform **that, png_byte colour_type,
+      png_byte bit_depth);
+} image_transform;
+typedef struct transform_display
+{
+   standard_display this;
+   /* Parameters */
+   png_modifier*              pm;
+   PNG_CONST image_transform* transform_list;
+   /* Local variables */
+   png_byte output_colour_type;
+   png_byte output_bit_depth;
+   /* Modifications (not necessarily used.) */
+   gama_modification gama_mod;
+   chrm_modification chrm_mod;
+   srgb_modification srgb_mod;
+} transform_display;
+/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
+static void
+transform_set_encoding(transform_display *this)
+{
+   /* Set up the png_modifier '_current' fields then use these to determine how
+    * to add appropriate chunks.
+    */
+   png_modifier *pm = this->pm;
+   modifier_set_encoding(pm);
+   if (modifier_color_encoding_is_set(pm))
+   {
+      if (modifier_color_encoding_is_sRGB(pm))
+         srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
+      else
+      {
+         /* Set gAMA and cHRM separately. */
+         gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
+         if (pm->current_encoding != 0)
+            chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
+      }
+   }
+}
+/* Three functions to end the list: */
+static void
+image_transform_ini_end(PNG_CONST image_transform *this,
+   transform_display *that)
+{
+   UNUSED(this)
+   UNUSED(that)
+}
+static void
+image_transform_set_end(PNG_CONST image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   UNUSED(this)
+   UNUSED(that)
+   UNUSED(pp)
+   UNUSED(pi)
+}
+/* At the end of the list recalculate the output image pixel value from the
+ * double precision values set up by the preceding 'mod' calls:
+ */
+static unsigned int
+sample_scale(double sample_value, unsigned int scale)
+{
+   sample_value = floor(sample_value * scale + .5);
+   /* Return NaN as 0: */
+   if (!(sample_value > 0))
+      sample_value = 0;
+   else if (sample_value > scale)
+      sample_value = scale;
+   return (unsigned int)sample_value;
+}
+static void
+image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
+    png_structp pp, PNG_CONST transform_display *display)
+{
+   PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
+   UNUSED(this)
+   UNUSED(pp)
+   UNUSED(display)
+   /* At the end recalculate the digitized red green and blue values according
+    * to the current sample_depth of the pixel.
+    *
+    * The sample value is simply scaled to the maximum, checking for over
+    * and underflow (which can both happen for some image transforms,
+    * including simple size scaling, though libpng doesn't do that at present.
+    */
+   that->red = sample_scale(that->redf, scale);
+   /* The error value is increased, at the end, according to the lowest sBIT
+    * value seen.  Common sense tells us that the intermediate integer
+    * representations are no more accurate than +/- 0.5 in the integral values,
+    * the sBIT allows the implementation to be worse than this.  In addition the
+    * PNG specification actually permits any error within the range (-1..+1),
+    * but that is ignored here.  Instead the final digitized value is compared,
+    * below to the digitized value of the error limits - this has the net effect
+    * of allowing (almost) +/-1 in the output value.  It's difficult to see how
+    * any algorithm that digitizes intermediate results can be more accurate.
+    */
+   that->rede += 1./(2*((1U<<that->red_sBIT)-1));
+   if (that->colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      that->green = sample_scale(that->greenf, scale);
+      that->blue = sample_scale(that->bluef, scale);
+      that->greene += 1./(2*((1U<<that->green_sBIT)-1));
+      that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
+   }
+   else
+   {
+      that->blue = that->green = that->red;
+      that->bluef = that->greenf = that->redf;
+      that->bluee = that->greene = that->rede;
+   }
+   if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
+      that->colour_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      that->alpha = sample_scale(that->alphaf, scale);
+      that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
+   }
+   else
+   {
+      that->alpha = scale; /* opaque */
+      that->alpha = 1;     /* Override this. */
+      that->alphae = 0;    /* It's exact ;-) */
+   }
+}
+/* Static 'end' structure: */
+static image_transform image_transform_end =
+{
+   "(end)", /* name */
+   1, /* enable */
+   0, /* list */
+   0, /* global_use */
+   0, /* local_use */
+   0, /* next */
+   image_transform_ini_end,
+   image_transform_set_end,
+   image_transform_mod_end,
+   0 /* never called, I want it to crash if it is! */
+};
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+static void
+transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
+    PNG_CONST image_transform *transform_list)
+{
+   memset(dp, 0, sizeof *dp);
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
+      pm->use_update_info);
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->transform_list = transform_list;
+   /* Local variable fields */
+   dp->output_colour_type = 255; /* invalid */
+   dp->output_bit_depth = 255;  /* invalid */
+}
+static void
+transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+   /* Now set the list of transforms. */
+   dp->transform_list->set(dp->transform_list, dp, pp, pi);
+   /* Update the info structure for these transforms: */
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+   /* And get the output information into the standard_display */
+   standard_info_part2(&dp->this, pp, pi, 1/*images*/);
+   /* Plus the extra stuff we need for the transform tests: */
+   dp->output_colour_type = png_get_color_type(pp, pi);
+   dp->output_bit_depth = png_get_bit_depth(pp, pi);
+   /* Validate the combination of colour type and bit depth that we are getting
+    * out of libpng; the semantics of something not in the PNG spec are, at
+    * best, unclear.
+    */
+   switch (dp->output_colour_type)
+   {
+   case PNG_COLOR_TYPE_PALETTE:
+      if (dp->output_bit_depth > 8) goto error;
+      /*FALL THROUGH*/
+   case PNG_COLOR_TYPE_GRAY:
+      if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
+         dp->output_bit_depth == 4)
+         break;
+      /*FALL THROUGH*/
+   default:
+      if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
+         break;
+      /*FALL THROUGH*/
+   error:
+      {
+         char message[128];
+         size_t pos;
+         pos = safecat(message, sizeof message, 0,
+            "invalid final bit depth: colour type(");
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, ") with bit depth: ");
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         png_error(pp, message);
+      }
+   }
+   /* Use a test pixel to check that the output agrees with what we expect -
+    * this avoids running the whole test if the output is unexpected.
+    */
+   {
+      image_pixel test_pixel;
+      memset(&test_pixel, 0, sizeof test_pixel);
+      test_pixel.colour_type = dp->this.colour_type; /* input */
+      test_pixel.bit_depth = dp->this.bit_depth;
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+         test_pixel.sample_depth = 8;
+      else
+         test_pixel.sample_depth = test_pixel.bit_depth;
+      /* Don't need sBIT here, but it must be set to non-zero to avoid
+       * arithmetic overflows.
+       */
+      test_pixel.have_tRNS = dp->this.is_transparent;
+      test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
+         test_pixel.alpha_sBIT = test_pixel.sample_depth;
+      dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
+      if (test_pixel.colour_type != dp->output_colour_type)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "colour type ");
+         pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
+         png_error(pp, message);
+      }
+      if (test_pixel.bit_depth != dp->output_bit_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0, "bit depth ");
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+         png_error(pp, message);
+      }
+      /* If both bit depth and colour type are correct check the sample depth.
+       * I believe these are both internal errors.
+       */
+      if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (test_pixel.sample_depth != 8) /* oops - internal error! */
+            png_error(pp, "pngvalid: internal: palette sample depth not 8");
+      }
+      else if (test_pixel.sample_depth != dp->output_bit_depth)
+      {
+         char message[128];
+         size_t pos = safecat(message, sizeof message, 0,
+            "internal: sample depth ");
+         pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+         pos = safecat(message, sizeof message, pos, " expected ");
+         pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
+         png_error(pp, message);
+      }
+   }
+}
+static void
+transform_info(png_structp pp, png_infop pi)
+{
+   transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
+      pp, pi);
+}
+static void
+transform_range_check(png_structp pp, unsigned int r, unsigned int g,
+   unsigned int b, unsigned int a, unsigned int in_digitized, double in,
+   unsigned int out, png_byte sample_depth, double err, double limit,
+   PNG_CONST char *name, double digitization_error)
+{
+   /* Compare the scaled, digitzed, values of our local calculation (in+-err)
+    * with the digitized values libpng produced;  'sample_depth' is the actual
+    * digitization depth of the libpng output colors (the bit depth except for
+    * palette images where it is always 8.)  The check on 'err' is to detect
+    * internal errors in pngvalid itself.
+    */
+   unsigned int max = (1U<<sample_depth)-1;
+   double in_min = ceil((in-err)*max - digitization_error);
+   double in_max = floor((in+err)*max + digitization_error);
+   if (err > limit || !(out >= in_min && out <= in_max))
+   {
+      char message[256];
+      size_t pos;
+      pos = safecat(message, sizeof message, 0, name);
+      pos = safecat(message, sizeof message, pos, " output value error: rgba(");
+      pos = safecatn(message, sizeof message, pos, r);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, g);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, b);
+      pos = safecat(message, sizeof message, pos, ",");
+      pos = safecatn(message, sizeof message, pos, a);
+      pos = safecat(message, sizeof message, pos, "): ");
+      pos = safecatn(message, sizeof message, pos, out);
+      pos = safecat(message, sizeof message, pos, " expected: ");
+      pos = safecatn(message, sizeof message, pos, in_digitized);
+      pos = safecat(message, sizeof message, pos, " (");
+      pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
+      pos = safecat(message, sizeof message, pos, "..");
+      pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
+      pos = safecat(message, sizeof message, pos, ")");
+      png_error(pp, message);
+   }
+}
+static void
+transform_image_validate(transform_display *dp, png_structp pp, png_infop pi)
+{
+   /* Constants for the loop below: */
+   PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
+   PNG_CONST png_byte in_ct = dp->this.colour_type;
+   PNG_CONST png_byte in_bd = dp->this.bit_depth;
+   PNG_CONST png_uint_32 w = dp->this.w;
+   PNG_CONST png_uint_32 h = dp->this.h;
+   PNG_CONST png_byte out_ct = dp->output_colour_type;
+   PNG_CONST png_byte out_bd = dp->output_bit_depth;
+   PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
+      PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
+   PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
+   PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
+   PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
+   PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
+   PNG_CONST int have_tRNS = dp->this.is_transparent;
+   double digitization_error;
+   store_palette out_palette;
+   png_uint_32 y;
+   UNUSED(pi)
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+   /* Read the palette corresponding to the output if the output colour type
+    * indicates a palette, othewise set out_palette to garbage.
+    */
+   if (out_ct == PNG_COLOR_TYPE_PALETTE)
+   {
+      /* Validate that the palette count itself has not changed - this is not
+       * expected.
+       */
+      int npalette = (-1);
+      (void)read_palette(out_palette, &npalette, pp, pi);
+      if (npalette != dp->this.npalette)
+         png_error(pp, "unexpected change in palette size");
+      digitization_error = .5;
+   }
+   else
+   {
+      png_byte in_sample_depth;
+      memset(out_palette, 0x5e, sizeof out_palette);
+      /* assume-8-bit-calculations means assume that if the input has 8 bit
+       * (or less) samples and the output has 16 bit samples the calculations
+       * will be done with 8 bit precision, not 16.
+       *
+       * TODO: fix this in libpng; png_set_expand_16 should cause 16 bit
+       * calculations to be used throughout.
+       */
+      if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
+         in_sample_depth = 8;
+      else
+         in_sample_depth = in_bd;
+      if (sample_depth != 16 || in_sample_depth > 8 ||
+         !dp->pm->calculations_use_input_precision)
+         digitization_error = .5;
+      /* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits:
+       */
+      else
+         digitization_error = .5 * 257;
+   }
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y);
+      png_uint_32 x;
+      /* The original, standard, row pre-transforms. */
+      png_byte std[STANDARD_ROWMAX];
+      transform_row(pp, std, in_ct, in_bd, y);
+      /* Go through each original pixel transforming it and comparing with what
+       * libpng did to the same pixel.
+       */
+      for (x=0; x<w; ++x)
+      {
+         image_pixel in_pixel, out_pixel;
+         unsigned int r, g, b, a;
+         /* Find out what we think the pixel should be: */
+         image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
+         in_pixel.red_sBIT = red_sBIT;
+         in_pixel.green_sBIT = green_sBIT;
+         in_pixel.blue_sBIT = blue_sBIT;
+         in_pixel.alpha_sBIT = alpha_sBIT;
+         in_pixel.have_tRNS = have_tRNS;
+         /* For error detection, below. */
+         r = in_pixel.red;
+         g = in_pixel.green;
+         b = in_pixel.blue;
+         a = in_pixel.alpha;
+         dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
+         /* Read the output pixel and compare it to what we got, we don't
+          * use the error field here, so no need to update sBIT.
+          */
+         image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
+         /* We don't expect changes to the index here even if the bit depth is
+          * changed.
+          */
+         if (in_ct == PNG_COLOR_TYPE_PALETTE &&
+            out_ct == PNG_COLOR_TYPE_PALETTE)
+         {
+            if (in_pixel.palette_index != out_pixel.palette_index)
+               png_error(pp, "unexpected transformed palette index");
+         }
+         /* Check the colours for palette images too - in fact the palette could
+          * be separately verified itself in most cases.
+          */
+         if (in_pixel.red != out_pixel.red)
+            transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
+               out_pixel.red, sample_depth, in_pixel.rede,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
+               digitization_error);
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.green != out_pixel.green)
+            transform_range_check(pp, r, g, b, a, in_pixel.green,
+               in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
+               digitization_error);
+         if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+            in_pixel.blue != out_pixel.blue)
+            transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
+               out_pixel.blue, sample_depth, in_pixel.bluee,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
+               digitization_error);
+         if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
+            in_pixel.alpha != out_pixel.alpha)
+            transform_range_check(pp, r, g, b, a, in_pixel.alpha,
+               in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
+               dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
+               digitization_error);
+      } /* pixel (x) loop */
+   } /* row (y) loop */
+   /* Record that something was actually checked to avoid a false positive. */
+   dp->this.ps->validated = 1;
+}
+static void
+transform_end(png_structp pp, png_infop pi)
+{
+   transform_display *dp = voidcast(transform_display*,
+      png_get_progressive_ptr(pp));
+   if (!dp->this.speed)
+      transform_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+/* A single test run. */
+static void
+transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
+    PNG_CONST image_transform* transform_listIn, PNG_CONST char * volatile name)
+{
+   transform_display d;
+   context(&pmIn->this, fault);
+   transform_display_init(&d, pmIn, idIn, transform_listIn);
+   Try
+   {
+      size_t pos = 0;
+      png_structp pp;
+      png_infop pi;
+      char full_name[256];
+      /* Make sure the encoding fields are correct and enter the required
+       * modifications.
+       */
+      transform_set_encoding(&d);
+      /* Add any modifications required by the transform list. */
+      d.transform_list->ini(d.transform_list, &d);
+      /* Add the color space information, if any, to the name. */
+      pos = safecat(full_name, sizeof full_name, pos, name);
+      pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
+      /* Get a png_struct for reading the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
+      standard_palette_init(&d.this);
+#     if 0
+         /* Logging (debugging only) */
+         {
+            char buffer[256];
+            (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
+               "running test");
+            fprintf(stderr, "%s\n", buffer);
+         }
+#     endif
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
+            transform_end);
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+         /* Check the header values: */
+         png_read_info(pp, pi);
+         /* Process the 'info' requirements. Only one image is generated */
+         transform_info_imp(&d, pp, pi);
+         sequential_row(&d.this, pp, pi, -1, 0);
+         if (!d.this.speed)
+            transform_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+      modifier_reset(d.pm);
+   }
+   Catch(fault)
+   {
+      modifier_reset((png_modifier*)fault);
+   }
+}
+/* The transforms: */
+#define ITSTRUCT(name) image_transform_##name
+#define ITDATA(name) image_transform_data_##name
+#define image_transform_ini image_transform_default_ini
+#define IT(name)\
+static image_transform ITSTRUCT(name) =\
+{\
+   #name,\
+   1, /*enable*/\
+   &PT, /*list*/\
+   0, /*global_use*/\
+   0, /*local_use*/\
+   0, /*next*/\
+   image_transform_ini,\
+   image_transform_png_set_##name##_set,\
+   image_transform_png_set_##name##_mod,\
+   image_transform_png_set_##name##_add\
+}
+#define PT ITSTRUCT(end) /* stores the previous transform */
+/* To save code: */
+static void
+image_transform_default_ini(PNG_CONST image_transform *this,
+    transform_display *that)
+{
+   this->next->ini(this->next, that);
+}
+static int
+image_transform_default_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   return 1;
+}
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_palette_to_rgb */
+static void
+image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_palette_to_rgb(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_palette_to_rgb_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   return colour_type == PNG_COLOR_TYPE_PALETTE;
+}
+IT(palette_to_rgb);
+#undef PT
+#define PT ITSTRUCT(palette_to_rgb)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_tRNS_to_alpha */
+static void
+image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
+   transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_tRNS_to_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
+   image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   /* LIBPNG BUG: this always forces palette images to RGB. */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   /* This effectively does an 'expand' only if there is some transparency to
+    * convert to an alpha channel.
+    */
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this);
+   /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
+   else
+   {
+      if (that->bit_depth < 8)
+         that->bit_depth =8;
+      if (that->sample_depth < 8)
+         that->sample_depth = 8;
+   }
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   /* We don't know yet whether there will be a tRNS chunk, but we know that
+    * this transformation should do nothing if there already is an alpha
+    * channel.
+    */
+   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+IT(tRNS_to_alpha);
+#undef PT
+#define PT ITSTRUCT(tRNS_to_alpha)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* png_set_gray_to_rgb */
+static void
+image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_gray_to_rgb(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   /* NOTE: we can actually pend the tRNS processing at this point because we
+    * can correctly recognize the original pixel value even though we have
+    * mapped the one gray channel to the three RGB ones, but in fact libpng
+    * doesn't do this, so we don't either.
+    */
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this);
+   /* Simply expand the bit depth and alter the colour type as required. */
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* RGB images have a bit depth at least equal to '8' */
+      if (that->bit_depth < 8)
+         that->sample_depth = that->bit_depth = 8;
+      /* And just changing the colour type works here because the green and blue
+       * channels are being maintained in lock-step with the red/gray:
+       */
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   }
+   else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_gray_to_rgb_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
+}
+IT(gray_to_rgb);
+#undef PT
+#define PT ITSTRUCT(gray_to_rgb)
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand */
+static void
+image_transform_png_set_expand_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   /* The general expand case depends on what the colour type is: */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   else if (that->bit_depth < 8) /* grayscale */
+      that->sample_depth = that->bit_depth = 8;
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this);
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_expand_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
+    * depth is at least 8 already.
+    */
+   return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+IT(expand);
+#undef PT
+#define PT ITSTRUCT(expand)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand_gray_1_2_4_to_8
+ * LIBPNG BUG: this just does an 'expand'
+ */
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_set(
+    PNG_CONST image_transform *this, transform_display *that, png_structp pp,
+    png_infop pi)
+{
+   png_set_expand_gray_1_2_4_to_8(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_mod(
+    PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
+    PNG_CONST transform_display *display)
+{
+   image_transform_png_set_expand_mod(this, that, pp, display);
+}
+static int
+image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   return image_transform_png_set_expand_add(this, that, colour_type,
+      bit_depth);
+}
+IT(expand_gray_1_2_4_to_8);
+#undef PT
+#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* png_set_expand_16 */
+static void
+image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_expand_16(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   /* Expect expand_16 to expand everything to 16 bits as a result of also
+    * causing 'expand' to happen.
+    */
+   if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+      image_pixel_convert_PLTE(that);
+   if (that->have_tRNS)
+      image_pixel_add_alpha(that, &display->this);
+   if (that->bit_depth < 16)
+      that->sample_depth = that->bit_depth = 16;
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_expand_16_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   this->next = *that;
+   *that = this;
+   /* expand_16 does something unless the bit depth is already 16. */
+   return bit_depth < 16;
+}
+IT(expand_16);
+#undef PT
+#define PT ITSTRUCT(expand_16)
+#endif /* PNG_READ_EXPAND_16_SUPPORTED */
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED  /* API added in 1.5.4 */
+/* png_set_scale_16 */
+static void
+image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_scale_16(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+   }
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_scale_16_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   this->next = *that;
+   *that = this;
+   return bit_depth > 8;
+}
+IT(scale_16);
+#undef PT
+#define PT ITSTRUCT(scale_16)
+#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
+#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
+/* png_set_strip_16 */
+static void
+image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_16(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   if (that->bit_depth == 16)
+   {
+      that->sample_depth = that->bit_depth = 8;
+      if (that->red_sBIT > 8) that->red_sBIT = 8;
+      if (that->green_sBIT > 8) that->green_sBIT = 8;
+      if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+      if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+      /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
+       * configuration option is set.  From 1.5.4 the flag is never set and the
+       * 'scale' API (above) must be used.
+       */
+#     ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
+#        if PNG_LIBPNG_VER >= 10504
+#           error PNG_READ_ACCURATE_SCALE should not be set
+#        endif
+         /* The strip 16 algorithm drops the low 8 bits rather than calculating
+          * 1/257, so we need to adjust the permitted errors appropriately:
+          * Notice that this is only relevant prior to the addition of the
+          * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
+          */
+         {
+            PNG_CONST double d = (255-128.5)/65535;
+            that->rede += d;
+            that->greene += d;
+            that->bluee += d;
+            that->alphae += d;
+         }
+#     endif
+   }
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_strip_16_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(colour_type)
+   this->next = *that;
+   *that = this;
+   return bit_depth > 8;
+}
+IT(strip_16);
+#undef PT
+#define PT ITSTRUCT(strip_16)
+#endif /* PNG_READ_16_TO_8_SUPPORTED */
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+/* png_set_strip_alpha */
+static void
+image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_strip_alpha(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_GRAY;
+   else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      that->colour_type = PNG_COLOR_TYPE_RGB;
+   that->have_tRNS = 0;
+   that->alphaf = 1;
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_strip_alpha_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
+}
+IT(strip_alpha);
+#undef PT
+#define PT ITSTRUCT(strip_alpha)
+#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
+ * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
+ *    png_fixed_point green)
+ * png_get_rgb_to_gray_status
+ *
+ * The 'default' test here uses values known to be used inside libpng:
+ *
+ *   red:    6968
+ *   green: 23434
+ *   blue:   2366
+ *
+ * These values are being retained for compatibility, along with the somewhat
+ * broken truncation calculation in the fast-and-inaccurate code path.  Older
+ * versions of libpng will fail the accuracy tests below because they use the
+ * truncation algorithm everywhere.
+ */
+#define data ITDATA(rgb_to_gray)
+static struct
+{
+   double gamma;      /* File gamma to use in processing */
+   /* The following are the parameters for png_set_rgb_to_gray: */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      double red_to_set;
+      double green_to_set;
+#  else
+      png_fixed_point red_to_set;
+      png_fixed_point green_to_set;
+#  endif
+   /* The actual coefficients: */
+   double red_coefficient;
+   double green_coefficient;
+   double blue_coefficient;
+   /* Set if the coeefficients have been overridden. */
+   int coefficients_overridden;
+} data;
+#undef image_transform_ini
+#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
+static void
+image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
+    transform_display *that)
+{
+   png_modifier *pm = that->pm;
+   PNG_CONST color_encoding *e = pm->current_encoding;
+   UNUSED(this)
+   /* Since we check the encoding this flag must be set: */
+   pm->test_uses_encoding = 1;
+   /* If 'e' is not NULL chromaticity information is present and either a cHRM
+    * or an sRGB chunk will be inserted.
+    */
+   if (e != 0)
+   {
+      /* Coefficients come from the encoding, but may need to be normalized to a
+       * white point Y of 1.0
+       */
+      PNG_CONST double whiteY = e->red.Y + e->green.Y + e->blue.Y;
+      data.red_coefficient = e->red.Y;
+      data.green_coefficient = e->green.Y;
+      data.blue_coefficient = e->blue.Y;
+      if (whiteY != 1)
+      {
+         data.red_coefficient /= whiteY;
+         data.green_coefficient /= whiteY;
+         data.blue_coefficient /= whiteY;
+      }
+   }
+   else
+   {
+      /* The default (built in) coeffcients, as above: */
+      data.red_coefficient = 6968 / 32768.;
+      data.green_coefficient = 23434 / 32768.;
+      data.blue_coefficient = 2366 / 32768.;
+   }
+   data.gamma = pm->current_gamma;
+   /* If not set then the calculations assume linear encoding (implicitly): */
+   if (data.gamma == 0)
+      data.gamma = 1;
+   /* The arguments to png_set_rgb_to_gray can override the coefficients implied
+    * by the color space encoding.  If doing exhaustive checks do the override
+    * in each case, otherwise do it randomly.
+    */
+   if (pm->test_exhaustive)
+   {
+      /* First time in coefficients_overridden is 0, the following sets it to 1,
+       * so repeat if it is set.  If a test fails this may mean we subsequently
+       * skip a non-override test, ignore that.
+       */
+      data.coefficients_overridden = !data.coefficients_overridden;
+      pm->repeat = data.coefficients_overridden != 0;
+   }
+   else
+      data.coefficients_overridden = random_choice();
+   if (data.coefficients_overridden)
+   {
+      /* These values override the color encoding defaults, simply use random
+       * numbers.
+       */
+      png_uint_32 ru;
+      double total;
+      RANDOMIZE(ru);
+      data.green_coefficient = total = (ru & 0xffff) / 65535.;
+      ru >>= 16;
+      data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
+      total += data.red_coefficient;
+      data.blue_coefficient = 1 - total;
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         data.red_to_set = data.red_coefficient;
+         data.green_to_set = data.green_coefficient;
+#     else
+         data.red_to_set = fix(data.red_coefficient);
+         data.green_to_set = fix(data.green_coefficient);
+#     endif
+      /* The following just changes the error messages: */
+      pm->encoding_ignored = 1;
+   }
+   else
+   {
+      data.red_to_set = -1;
+      data.green_to_set = -1;
+   }
+   /* Adjust the error limit in the png_modifier because of the larger errors
+    * produced in the digitization during the gamma handling.
+    */
+   if (data.gamma != 1) /* Use gamma tables */
+   {
+      if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
+      {
+         /* The 16 bit case ends up producing a maximum error of about
+          * +/-5 in 65535, allow for +/-8 with the given gamma.
+          */
+         that->pm->limit += pow(8./65535, data.gamma);
+      }
+      else
+      {
+         /* Rounding to 8 bits in the linear space causes massive errors which
+          * will trigger the error check in transform_range_check.  Fix that
+          * here by taking the gamma encoding into account.
+          */
+         that->pm->limit += pow(1./255, data.gamma);
+      }
+   }
+   else
+   {
+      /* With no gamma correction a large error comes from the truncation of the
+       * calculation in the 8 bit case, allow for that here.
+       */
+      if (that->this.bit_depth != 16)
+         that->pm->limit += 4E-3;
+   }
+}
+static void
+image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   PNG_CONST int error_action = 1; /* no error, no defines in png.h */
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
+#  else
+      png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
+         data.green_to_set);
+#  endif
+#  ifdef PNG_READ_cHRM_SUPPORTED
+      if (that->pm->current_encoding != 0)
+      {
+         /* We have an encoding so a cHRM chunk may have been set; if so then
+          * check that the libpng APIs give the correct (X,Y,Z) values within
+          * some margin of error for the round trip through the chromaticity
+          * form.
+          */
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+#           define API_function png_get_cHRM_XYZ
+#           define API_form "FP"
+#           define API_type double
+#           define API_cvt(x) (x)
+#        else
+#           define API_function png_get_cHRM_XYZ_fixed
+#           define API_form "fixed"
+#           define API_type png_fixed_point
+#           define API_cvt(x) ((double)(x)/PNG_FP_1)
+#        endif
+         API_type rX, gX, bX;
+         API_type rY, gY, bY;
+         API_type rZ, gZ, bZ;
+         if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
+               & PNG_INFO_cHRM) != 0)
+         {
+            double maxe;
+            PNG_CONST char *el;
+            color_encoding e, o;
+            /* Expect libpng to return a normalized result, but the original
+             * color space encoding may not be normalized.
+             */
+            modifier_current_encoding(that->pm, &o);
+            normalize_color_encoding(&o);
+            /* Sanity check the pngvalid code - the coefficients should match
+             * the normalized Y values of the encoding unless they were
+             * overridden.
+             */
+            if (data.red_to_set == -1 && data.green_to_set == -1 &&
+               (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
+               fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
+               fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
+               png_error(pp, "internal pngvalid cHRM coefficient error");
+            /* Generate a colour space encoding. */
+            e.gamma = o.gamma; /* not used */
+            e.red.X = API_cvt(rX);
+            e.red.Y = API_cvt(rY);
+            e.red.Z = API_cvt(rZ);
+            e.green.X = API_cvt(gX);
+            e.green.Y = API_cvt(gY);
+            e.green.Z = API_cvt(gZ);
+            e.blue.X = API_cvt(bX);
+            e.blue.Y = API_cvt(bY);
+            e.blue.Z = API_cvt(bZ);
+            /* This should match the original one from the png_modifier, within
+             * the range permitted by the libpng fixed point representation.
+             */
+            maxe = 0;
+            el = "-"; /* Set to element name with error */
+#           define CHECK(col,x)\
+            {\
+               double err = fabs(o.col.x - e.col.x);\
+               if (err > maxe)\
+               {\
+                  maxe = err;\
+                  el = #col "(" #x ")";\
+               }\
+            }
+            CHECK(red,X)
+            CHECK(red,Y)
+            CHECK(red,Z)
+            CHECK(green,X)
+            CHECK(green,Y)
+            CHECK(green,Z)
+            CHECK(blue,X)
+            CHECK(blue,Y)
+            CHECK(blue,Z)
+            /* Here in both fixed and floating cases to check the values read
+             * from the cHRm chunk.  PNG uses fixed point in the cHRM chunk, so
+             * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
+             */
+            if (maxe >= 1E-5)
+            {
+               size_t pos = 0;
+               char buffer[256];
+               pos = safecat(buffer, sizeof buffer, pos, API_form);
+               pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
+               pos = safecat(buffer, sizeof buffer, pos, el);
+               pos = safecat(buffer, sizeof buffer, pos, " error: ");
+               pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
+               pos = safecat(buffer, sizeof buffer, pos, " ");
+               /* Print the color space without the gamma value: */
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
+               pos = safecat(buffer, sizeof buffer, pos, " -> ");
+               pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
+               png_error(pp, buffer);
+            }
+         }
+      }
+#  endif /* READ_cHRM */
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
+   {
+      double gray, err;
+      if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+         image_pixel_convert_PLTE(that);
+      /* Image now has RGB channels... */
+      {
+         PNG_CONST png_modifier *pm = display->pm;
+         PNG_CONST unsigned int sample_depth = that->sample_depth;
+         int isgray;
+         double r, g, b;
+         double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
+         /* Do this using interval arithmetic, otherwise it is too difficult to
+          * handle the errors correctly.
+          *
+          * To handle the gamma correction work out the upper and lower bounds
+          * of the digitized value.  Assume rounding here - normally the values
+          * will be identical after this operation if there is only one
+          * transform, feel free to delete the png_error checks on this below in
+          * the future (this is just me trying to ensure it works!)
+          */
+         r = rlo = rhi = that->redf;
+         rlo -= that->rede;
+         rlo = digitize(pm, rlo, sample_depth, 1/*round*/);
+         rhi += that->rede;
+         rhi = digitize(pm, rhi, sample_depth, 1/*round*/);
+         g = glo = ghi = that->greenf;
+         glo -= that->greene;
+         glo = digitize(pm, glo, sample_depth, 1/*round*/);
+         ghi += that->greene;
+         ghi = digitize(pm, ghi, sample_depth, 1/*round*/);
+         b = blo = bhi = that->bluef;
+         blo -= that->bluee;
+         blo = digitize(pm, blo, sample_depth, 1/*round*/);
+         bhi += that->greene;
+         bhi = digitize(pm, bhi, sample_depth, 1/*round*/);
+         isgray = r==g && g==b;
+         if (data.gamma != 1)
+         {
+            PNG_CONST double power = 1/data.gamma;
+            PNG_CONST double abse = abserr(pm, sample_depth, sample_depth);
+            /* 'abse' is the absolute error permitted in linear calculations. It
+             * is used here to capture the error permitted in the handling
+             * (undoing) of the gamma encoding.  Once again digitization occurs
+             * to handle the upper and lower bounds of the values.  This is
+             * where the real errors are introduced.
+             */
+            r = pow(r, power);
+            rlo = digitize(pm, pow(rlo, power)-abse, sample_depth, 1);
+            rhi = digitize(pm, pow(rhi, power)+abse, sample_depth, 1);
+            g = pow(g, power);
+            glo = digitize(pm, pow(glo, power)-abse, sample_depth, 1);
+            ghi = digitize(pm, pow(ghi, power)+abse, sample_depth, 1);
+            b = pow(b, power);
+            blo = digitize(pm, pow(blo, power)-abse, sample_depth, 1);
+            bhi = digitize(pm, pow(bhi, power)+abse, sample_depth, 1);
+         }
+         /* Now calculate the actual gray values.  Although the error in the
+          * coefficients depends on whether they were specified on the command
+          * line (in which case truncation to 15 bits happened) or not (rounding
+          * was used) the maxium error in an individual coefficient is always
+          * 1/32768, because even in the rounding case the requirement that
+          * coefficients add up to 32768 can cause a larger rounding error.
+          *
+          * The only time when rounding doesn't occur in 1.5.5 and later is when
+          * the non-gamma code path is used for less than 16 bit data.
+          */
+         gray = r * data.red_coefficient + g * data.green_coefficient +
+            b * data.blue_coefficient;
+         {
+            PNG_CONST int do_round = data.gamma != 1 || sample_depth == 16;
+            PNG_CONST double ce = 1. / 32768;
+            graylo = digitize(pm, rlo * (data.red_coefficient-ce) +
+               glo * (data.green_coefficient-ce) +
+               blo * (data.blue_coefficient-ce), sample_depth, do_round);
+            if (graylo <= 0)
+               graylo = 0;
+            grayhi = digitize(pm, rhi * (data.red_coefficient+ce) +
+               ghi * (data.green_coefficient+ce) +
+               bhi * (data.blue_coefficient+ce), sample_depth, do_round);
+            if (grayhi >= 1)
+               grayhi = 1;
+         }
+         /* And invert the gamma. */
+         if (data.gamma != 1)
+         {
+            PNG_CONST double power = data.gamma;
+            gray = pow(gray, power);
+            graylo = digitize(pm, pow(graylo, power), sample_depth, 1);
+            grayhi = digitize(pm, pow(grayhi, power), sample_depth, 1);
+         }
+         /* Now the error can be calculated.
+          *
+          * If r==g==b because there is no overall gamma correction libpng
+          * currently preserves the original value.
+          */
+         if (isgray)
+            err = (that->rede + that->greene + that->bluee)/3;
+         else
+         {
+            err = fabs(grayhi-gray);
+            if (fabs(gray - graylo) > err)
+               err = fabs(graylo-gray);
+            /* Check that this worked: */
+            if (err > display->pm->limit)
+            {
+               size_t pos = 0;
+               char buffer[128];
+               pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+               pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+               pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+               pos = safecatd(buffer, sizeof buffer, pos,
+                  display->pm->limit, 6);
+               png_error(pp, buffer);
+            }
+         }
+      }
+      that->bluef = that->greenf = that->redf = gray;
+      that->bluee = that->greene = that->rede = err;
+      /* The sBIT is the minium of the three colour channel sBITs. */
+      if (that->red_sBIT > that->green_sBIT)
+         that->red_sBIT = that->green_sBIT;
+      if (that->red_sBIT > that->blue_sBIT)
+         that->red_sBIT = that->blue_sBIT;
+      that->blue_sBIT = that->green_sBIT = that->red_sBIT;
+      /* And remove the colour bit in the type: */
+      if (that->colour_type == PNG_COLOR_TYPE_RGB)
+         that->colour_type = PNG_COLOR_TYPE_GRAY;
+      else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+   }
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_rgb_to_gray_add(image_transform *this,
+    PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+   UNUSED(bit_depth)
+   this->next = *that;
+   *that = this;
+   return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
+}
+#undef data
+IT(rgb_to_gray);
+#undef PT
+#define PT ITSTRUCT(rgb_to_gray)
+#undef image_transform_ini
+#define image_transform_ini image_transform_default_ini
+#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* png_set_background(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand, double background_gamma)
+ * png_set_background_fixed(png_structp, png_const_color_16p background_color,
+ *    int background_gamma_code, int need_expand,
+ *    png_fixed_point background_gamma)
+ *
+ * As with rgb_to_gray this ignores the gamma (at present.)
+*/
+#define data ITDATA(background)
+static image_pixel data;
+static void
+image_transform_png_set_background_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_byte colour_type, bit_depth;
+   png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
+   png_color_16 back;
+   /* We need a background colour, because we don't know exactly what transforms
+    * have been set we have to supply the colour in the original file format and
+    * so we need to know what that is!  The background colour is stored in the
+    * transform_display.
+    */
+   RANDOMIZE(random_bytes);
+   /* Read the random value, for colour type 3 the background colour is actually
+    * expressed as a 24bit rgb, not an index.
+    */
+   colour_type = that->this.colour_type;
+   if (colour_type == 3)
+   {
+      colour_type = PNG_COLOR_TYPE_RGB;
+      bit_depth = 8;
+   }
+   else
+      bit_depth = that->this.bit_depth;
+   image_pixel_init(&data, random_bytes, colour_type,
+      bit_depth, 0/*x*/, 0/*unused: palette*/);
+   /* Extract the background colour from this image_pixel, but make sure the
+    * unused fields of 'back' are garbage.
+    */
+   RANDOMIZE(back);
+   if (colour_type & PNG_COLOR_MASK_COLOR)
+   {
+      back.red = (png_uint_16)data.red;
+      back.green = (png_uint_16)data.green;
+      back.blue = (png_uint_16)data.blue;
+   }
+   else
+      back.gray = (png_uint_16)data.red;
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/,
+         0);
+#  else
+      png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE,
+         1/*need expand*/, 0);
+#  endif
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_background_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   /* Check for tRNS first: */
+   if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
+      image_pixel_add_alpha(that, &display->this);
+   /* This is only necessary if the alpha value is less than 1. */
+   if (that->alphaf < 1)
+   {
+      /* Now we do the background calculation without any gamma correction. */
+      if (that->alphaf <= 0)
+      {
+         that->redf = data.redf;
+         that->greenf = data.greenf;
+         that->bluef = data.bluef;
+         that->rede = data.rede;
+         that->greene = data.greene;
+         that->bluee = data.bluee;
+         that->red_sBIT= data.red_sBIT;
+         that->green_sBIT= data.green_sBIT;
+         that->blue_sBIT= data.blue_sBIT;
+      }
+      else /* 0 < alpha < 1 */
+      {
+         double alf = 1 - that->alphaf;
+         that->redf = that->redf * that->alphaf + data.redf * alf;
+         that->rede = that->rede * that->alphaf + data.rede * alf +
+            DBL_EPSILON;
+         that->greenf = that->greenf * that->alphaf + data.greenf * alf;
+         that->greene = that->greene * that->alphaf + data.greene * alf +
+            DBL_EPSILON;
+         that->bluef = that->bluef * that->alphaf + data.bluef * alf;
+         that->bluee = that->bluee * that->alphaf + data.bluee * alf +
+            DBL_EPSILON;
+      }
+      /* Remove the alpha type and set the alpha (not in that order.) */
+      that->alphaf = 1;
+      that->alphae = 0;
+      if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         that->colour_type = PNG_COLOR_TYPE_RGB;
+      else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+         that->colour_type = PNG_COLOR_TYPE_GRAY;
+      /* PNG_COLOR_TYPE_PALETTE is not changed */
+   }
+   this->next->mod(this->next, that, pp, display);
+}
+#define image_transform_png_set_background_add image_transform_default_add
+#undef data
+IT(background);
+#undef PT
+#define PT ITSTRUCT(background)
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+/* This may just be 'end' if all the transforms are disabled! */
+static image_transform *PNG_CONST image_transform_first = &PT;
+static void
+transform_enable(PNG_CONST char *name)
+{
+   /* Everything starts out enabled, so if we see an 'enable' disabled
+    * everything else the first time round.
+    */
+   static int all_disabled = 0;
+   int found_it = 0;
+   image_transform *list = image_transform_first;
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 1;
+         found_it = 1;
+      }
+      else if (!all_disabled)
+         list->enable = 0;
+      list = list->list;
+   }
+   all_disabled = 1;
+   if (!found_it)
+   {
+      fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
+         name);
+      exit(1);
+   }
+}
+static void
+transform_disable(PNG_CONST char *name)
+{
+   image_transform *list = image_transform_first;
+   while (list != &image_transform_end)
+   {
+      if (strcmp(list->name, name) == 0)
+      {
+         list->enable = 0;
+         return;
+      }
+      list = list->list;
+   }
+   fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
+      name);
+   exit(1);
+}
+static void
+image_transform_reset_count(void)
+{
+   image_transform *next = image_transform_first;
+   int count = 0;
+   while (next != &image_transform_end)
+   {
+      next->local_use = 0;
+      next->next = 0;
+      next = next->list;
+      ++count;
+   }
+   /* This can only happen if we every have more than 32 transforms (excluding
+    * the end) in the list.
+    */
+   if (count > 32) abort();
+}
+static int
+image_transform_test_counter(png_uint_32 counter, unsigned int max)
+{
+   /* Test the list to see if there is any point contining, given a current
+    * counter and a 'max' value.
+    */
+   image_transform *next = image_transform_first;
+   while (next != &image_transform_end)
+   {
+      /* For max 0 or 1 continue until the counter overflows: */
+      counter >>= 1;
+      /* Continue if any entry hasn't reacked the max. */
+      if (max > 1 && next->local_use < max)
+         return 1;
+      next = next->list;
+   }
+   return max <= 1 && counter == 0;
+}
+static png_uint_32
+image_transform_add(PNG_CONST image_transform **this, unsigned int max,
+   png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
+   png_byte colour_type, png_byte bit_depth)
+{
+   for (;;) /* until we manage to add something */
+   {
+      png_uint_32 mask;
+      image_transform *list;
+      /* Find the next counter value, if the counter is zero this is the start
+       * of the list.  This routine always returns the current counter (not the
+       * next) so it returns 0 at the end and expects 0 at the beginning.
+       */
+      if (counter == 0) /* first time */
+      {
+         image_transform_reset_count();
+         if (max <= 1)
+            counter = 1;
+         else
+            counter = random_32();
+      }
+      else /* advance the counter */
+      {
+         switch (max)
+         {
+            case 0:  ++counter; break;
+            case 1:  counter <<= 1; break;
+            default: counter = random_32(); break;
+         }
+      }
+      /* Now add all these items, if possible */
+      *this = &image_transform_end;
+      list = image_transform_first;
+      mask = 1;
+      /* Go through the whole list adding anything that the counter selects: */
+      while (list != &image_transform_end)
+      {
+         if ((counter & mask) != 0 && list->enable &&
+             (max == 0 || list->local_use < max))
+         {
+            /* Candidate to add: */
+            if (list->add(list, this, colour_type, bit_depth) || max == 0)
+            {
+               /* Added, so add to the name too. */
+               *pos = safecat(name, sizeof_name, *pos, " +");
+               *pos = safecat(name, sizeof_name, *pos, list->name);
+            }
+            else
+            {
+               /* Not useful and max>0, so remove it from *this: */
+               *this = list->next;
+               list->next = 0;
+               /* And, since we know it isn't useful, stop it being added again
+                * in this run:
+                */
+               list->local_use = max;
+            }
+         }
+         mask <<= 1;
+         list = list->list;
+      }
+      /* Now if anything was added we have something to do. */
+      if (*this != &image_transform_end)
+         return counter;
+      /* Nothing added, but was there anything in there to add? */
+      if (!image_transform_test_counter(counter, max))
+         return 0;
+   }
+}
+#ifdef THIS_IS_THE_PROFORMA
+static void
+image_transform_png_set_@_set(PNG_CONST image_transform *this,
+    transform_display *that, png_structp pp, png_infop pi)
+{
+   png_set_@(pp);
+   this->next->set(this->next, that, pp, pi);
+}
+static void
+image_transform_png_set_@_mod(PNG_CONST image_transform *this,
+    image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+   this->next->mod(this->next, that, pp, display);
+}
+static int
+image_transform_png_set_@_add(image_transform *this,
+    PNG_CONST image_transform **that, char *name, size_t sizeof_name,
+    size_t *pos, png_byte colour_type, png_byte bit_depth)
+{
+   this->next = *that;
+   *that = this;
+   *pos = safecat(name, sizeof_name, *pos, " +@");
+   return 1;
+}
+IT(@);
+#endif
+/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
+ *    int maximum_colors, png_const_uint_16p histogram, int full_quantize)
+ *
+ * Very difficult to validate this!
+ */
+/*NOTE: TBD NYI */
+/* The data layout transforms are handled by swapping our own channel data,
+ * necessarily these need to happen at the end of the transform list because the
+ * semantic of the channels changes after these are executed.  Some of these,
+ * like set_shift and set_packing, can't be done at present because they change
+ * the layout of the data at the sub-sample level so sample() won't get the
+ * right answer.
+ */
+/* png_set_invert_alpha */
+/*NOTE: TBD NYI */
+/* png_set_bgr */
+/*NOTE: TBD NYI */
+/* png_set_swap_alpha */
+/*NOTE: TBD NYI */
+/* png_set_swap */
+/*NOTE: TBD NYI */
+/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/*NOTE: TBD NYI */
+/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/*NOTE: TBD NYI */
+/* png_set_packing */
+/*NOTE: TBD NYI */
+/* png_set_packswap */
+/*NOTE: TBD NYI */
+/* png_set_invert_mono */
+/*NOTE: TBD NYI */
+/* png_set_shift(png_structp, png_const_color_8p true_bits) */
+/*NOTE: TBD NYI */
+static void
+perform_transform_test(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   int palette_number = 0;
+   while (next_format(&colour_type, &bit_depth, &palette_number))
+   {
+      png_uint_32 counter = 0;
+      size_t base_pos;
+      char name[64];
+      base_pos = safecat(name, sizeof name, 0, "transform:");
+      for (;;)
+      {
+         size_t pos = base_pos;
+         PNG_CONST image_transform *list = 0;
+         /* 'max' is currently hardwired to '1'; this should be settable on the
+          * command line.
+          */
+         counter = image_transform_add(&list, 1/*max*/, counter,
+            name, sizeof name, &pos, colour_type, bit_depth);
+         if (counter == 0)
+            break;
+         /* The command line can change this to checking interlaced images. */
+         do
+         {
+            pm->repeat = 0;
+            transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
+               pm->interlace_type, 0, 0, 0), list, name);
+            if (fail(pm))
+               return;
+         }
+         while (pm->repeat);
+      }
+   }
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+/********************************* GAMMA TESTS ********************************/
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+typedef struct gamma_display
+{
+   standard_display this;
+   /* Parameters */
+   png_modifier*    pm;
+   double           file_gamma;
+   double           screen_gamma;
+   double           background_gamma;
+   png_byte         sbit;
+   int              threshold_test;
+   int              use_input_precision;
+   int              scale16;
+   int              expand16;
+   int              do_background;
+   png_color_16     background_color;
+   /* Local variables */
+   double       maxerrout;
+   double       maxerrpc;
+   double       maxerrabs;
+} gamma_display;
+#define ALPHA_MODE_OFFSET 4
+static void
+gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
+    double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
+    int use_input_precision, int scale16, int expand16,
+    int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color,
+    double background_gamma)
+{
+   /* Standard fields */
+   standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
+      pm->use_update_info);
+   /* Parameter fields */
+   dp->pm = pm;
+   dp->file_gamma = file_gamma;
+   dp->screen_gamma = screen_gamma;
+   dp->background_gamma = background_gamma;
+   dp->sbit = sbit;
+   dp->threshold_test = threshold_test;
+   dp->use_input_precision = use_input_precision;
+   dp->scale16 = scale16;
+   dp->expand16 = expand16;
+   dp->do_background = do_background;
+   if (do_background && pointer_to_the_background_color != 0)
+      dp->background_color = *pointer_to_the_background_color;
+   else
+      memset(&dp->background_color, 0, sizeof dp->background_color);
+   /* Local variable fields */
+   dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
+}
+static void
+gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
+{
+   /* Reuse the standard stuff as appropriate. */
+   standard_info_part1(&dp->this, pp, pi);
+   /* If requested strip 16 to 8 bits - this is handled automagically below
+    * because the output bit depth is read from the library.  Note that there
+    * are interactions with sBIT but, internally, libpng makes sbit at most
+    * PNG_MAX_GAMMA_8 when doing the following.
+    */
+   if (dp->scale16)
+#     ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+         png_set_scale_16(pp);
+#     else
+         /* The following works both in 1.5.4 and earlier versions: */
+#        ifdef PNG_READ_16_TO_8_SUPPORTED
+            png_set_strip_16(pp);
+#        else
+            png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
+#        endif
+#     endif
+   if (dp->expand16)
+#     ifdef PNG_READ_EXPAND_16_SUPPORTED
+         png_set_expand_16(pp);
+#     else
+         png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
+#     endif
+   if (dp->do_background >= ALPHA_MODE_OFFSET)
+   {
+#     ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      {
+         /* This tests the alpha mode handling, if supported. */
+         int mode = dp->do_background - ALPHA_MODE_OFFSET;
+         /* The gamma value is the output gamma, and is in the standard,
+          * non-inverted, represenation.  It provides a default for the PNG file
+          * gamma, but since the file has a gAMA chunk this does not matter.
+          */
+         PNG_CONST double sg = dp->screen_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            PNG_CONST png_fixed_point g = fix(sg);
+#        endif
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_alpha_mode(pp, mode, sg);
+#        else
+            png_set_alpha_mode_fixed(pp, mode, g);
+#        endif
+         /* However, for the standard Porter-Duff algorithm the output defaults
+          * to be linear, so if the test requires non-linear output it must be
+          * corrected here.
+          */
+         if (mode == PNG_ALPHA_STANDARD && sg != 1)
+         {
+#           ifdef PNG_FLOATING_POINT_SUPPORTED
+               png_set_gamma(pp, sg, dp->file_gamma);
+#           else
+               png_fixed_point f = fix(dp->file_gamma);
+               png_set_gamma_fixed(pp, g, f);
+#           endif
+         }
+      }
+#     else
+         png_error(pp, "alpha mode handling not supported");
+#     endif
+   }
+   else
+   {
+      /* Set up gamma processing. */
+#     ifdef PNG_FLOATING_POINT_SUPPORTED
+         png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
+#     else
+      {
+         png_fixed_point s = fix(dp->screen_gamma);
+         png_fixed_point f = fix(dp->file_gamma);
+         png_set_gamma_fixed(pp, s, f);
+      }
+#     endif
+      if (dp->do_background)
+      {
+#     ifdef PNG_READ_BACKGROUND_SUPPORTED
+         /* NOTE: this assumes the caller provided the correct background gamma!
+          */
+         PNG_CONST double bg = dp->background_gamma;
+#        ifndef PNG_FLOATING_POINT_SUPPORTED
+            PNG_CONST png_fixed_point g = fix(bg);
+#        endif
+#        ifdef PNG_FLOATING_POINT_SUPPORTED
+            png_set_background(pp, &dp->background_color, dp->do_background,
+               0/*need_expand*/, bg);
+#        else
+            png_set_background_fixed(pp, &dp->background_color,
+               dp->do_background, 0/*need_expand*/, g);
+#        endif
+#     else
+         png_error(pp, "png_set_background not supported");
+#     endif
+      }
+   }
+   {
+      int i = dp->this.use_update_info;
+      /* Always do one call, even if use_update_info is 0. */
+      do
+         png_read_update_info(pp, pi);
+      while (--i > 0);
+   }
+   /* Now we may get a different cbRow: */
+   standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
+}
+static void
+gamma_info(png_structp pp, png_infop pi)
+{
+   gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
+      pi);
+}
+/* Validate a single component value - the routine gets the input and output
+ * sample values as unscaled PNG component values along with a cache of all the
+ * information required to validate the values.
+ */
+typedef struct validate_info
+{
+   png_structp  pp;
+   gamma_display *dp;
+   png_byte sbit;
+   int use_input_precision;
+   int do_background;
+   int scale16;
+   unsigned int sbit_max;
+   unsigned int isbit_shift;
+   unsigned int outmax;
+   double gamma_correction; /* Overall correction required. */
+   double file_inverse;     /* Inverse of file gamma. */
+   double screen_gamma;
+   double screen_inverse;   /* Inverse of screen gamma. */
+   double background_red;   /* Linear background value, red or gray. */
+   double background_green;
+   double background_blue;
+   double maxabs;
+   double maxpc;
+   double maxcalc;
+   double maxout;
+   double maxout_total;     /* Total including quantization error */
+   double outlog;
+   int    outquant;
+}
+validate_info;
+static void
+init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp,
+    int in_depth, int out_depth)
+{
+   PNG_CONST unsigned int outmax = (1U<<out_depth)-1;
+   vi->pp = pp;
+   vi->dp = dp;
+   if (dp->sbit > 0 && dp->sbit < in_depth)
+   {
+      vi->sbit = dp->sbit;
+      vi->isbit_shift = in_depth - dp->sbit;
+   }
+   else
+   {
+      vi->sbit = (png_byte)in_depth;
+      vi->isbit_shift = 0;
+   }
+   vi->sbit_max = (1U << vi->sbit)-1;
+   /* This mimics the libpng threshold test, '0' is used to prevent gamma
+    * correction in the validation test.
+    */
+   vi->screen_gamma = dp->screen_gamma;
+   if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
+      vi->screen_gamma = vi->screen_inverse = 0;
+   else
+      vi->screen_inverse = 1/vi->screen_gamma;
+   vi->use_input_precision = dp->use_input_precision;
+   vi->outmax = outmax;
+   vi->maxabs = abserr(dp->pm, in_depth, out_depth);
+   vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
+   vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
+   vi->maxout = outerr(dp->pm, in_depth, out_depth);
+   vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
+   vi->maxout_total = vi->maxout + vi->outquant * .5;
+   vi->outlog = outlog(dp->pm, in_depth, out_depth);
+   if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+      (dp->this.colour_type == 3 && dp->this.is_transparent))
+   {
+      vi->do_background = dp->do_background;
+      if (vi->do_background != 0)
+      {
+         PNG_CONST double bg_inverse = 1/dp->background_gamma;
+         double r, g, b;
+         /* Caller must at least put the gray value into the red channel */
+         r = dp->background_color.red; r /= outmax;
+         g = dp->background_color.green; g /= outmax;
+         b = dp->background_color.blue; b /= outmax;
+#     if 0
+         /* libpng doesn't do this optimization, if we do pngvalid will fail.
+          */
+         if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
+#     endif
+         {
+            r = pow(r, bg_inverse);
+            g = pow(g, bg_inverse);
+            b = pow(b, bg_inverse);
+         }
+         vi->background_red = r;
+         vi->background_green = g;
+         vi->background_blue = b;
+      }
+   }
+   else
+      vi->do_background = 0;
+   if (vi->do_background == 0)
+      vi->background_red = vi->background_green = vi->background_blue = 0;
+   vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
+   if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
+      vi->gamma_correction = 0;
+   vi->file_inverse = 1/dp->file_gamma;
+   if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
+      vi->file_inverse = 0;
+   vi->scale16 = dp->scale16;
+}
+/* This function handles composition of a single non-alpha component.  The
+ * argument is the input sample value, in the range 0..1, and the alpha value.
+ * The result is the composed, linear, input sample.  If alpha is less than zero
+ * this is the alpha component and the function should not be called!
+ */
+static double
+gamma_component_compose(int do_background, double input_sample, double alpha,
+   double background, int *compose)
+{
+   switch (do_background)
+   {
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+      case PNG_BACKGROUND_GAMMA_FILE:
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         /* Standard PNG background processing. */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample = input_sample * alpha + background * (1-alpha);
+               if (compose != NULL)
+                  *compose = 1;
+            }
+            else
+               input_sample = background;
+         }
+         break;
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         /* The components are premultiplied in either case and the output is
+          * gamma encoded (to get standard Porter-Duff we expect the output
+          * gamma to be set to 1.0!)
+          */
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         /* The optimization is that the partial-alpha entries are linear
+          * while the opaque pixels are gamma encoded, but this only affects the
+          * output encoding.
+          */
+         if (alpha < 1)
+         {
+            if (alpha > 0)
+            {
+               input_sample *= alpha;
+               if (compose != NULL)
+                  *compose = 1;
+            }
+            else
+               input_sample = 0;
+         }
+         break;
+#endif
+      default:
+         /* Standard cases where no compositing is done (so the component
+          * value is already correct.)
+          */
+         break;
+   }
+   return input_sample;
+}
+/* This API returns the encoded *input* component, in the range 0..1 */
+static double
+gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
+    PNG_CONST unsigned int id, PNG_CONST unsigned int od,
+    PNG_CONST double alpha /* <0 for the alpha channel itself */,
+    PNG_CONST double background /* component background value */)
+{
+   PNG_CONST unsigned int isbit = id >> vi->isbit_shift;
+   PNG_CONST unsigned int sbit_max = vi->sbit_max;
+   PNG_CONST unsigned int outmax = vi->outmax;
+   PNG_CONST int do_background = vi->do_background;
+   double i;
+   /* First check on the 'perfect' result obtained from the digitized input
+    * value, id, and compare this against the actual digitized result, 'od'.
+    * 'i' is the input result in the range 0..1:
+    */
+   i = isbit; i /= sbit_max;
+   /* Check for the fast route: if we don't do any background composition or if
+    * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
+    * just use the gamma_correction field to correct to the final output gamma.
+    */
+   if (alpha == 1 /* opaque pixel component */ || !do_background
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
+#endif
+      || (alpha < 0 /* alpha channel */
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
+#endif
+      ))
+   {
+      /* Then get the gamma corrected version of 'i' and compare to 'od', any
+       * error less than .5 is insignificant - just quantization of the output
+       * value to the nearest digital value (nevertheless the error is still
+       * recorded - it's interesting ;-)
+       */
+      double encoded_sample = i;
+      double encoded_error;
+      /* alpha less than 0 indicates the alpha channel, which is always linear
+       */
+      if (alpha >= 0 && vi->gamma_correction > 0)
+         encoded_sample = pow(encoded_sample, vi->gamma_correction);
+      encoded_sample *= outmax;
+      encoded_error = fabs(od-encoded_sample);
+      if (encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+      if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
+         return i;
+   }
+   /* The slow route - attempt to do linear calculations. */
+   /* There may be an error, or background processing is required, so calculate
+    * the actual sample values - unencoded light intensity values.  Note that in
+    * practice these are not completely unencoded because they include a
+    * 'viewing correction' to decrease or (normally) increase the perceptual
+    * contrast of the image.  There's nothing we can do about this - we don't
+    * know what it is - so assume the unencoded value is perceptually linear.
+    */
+   {
+      double input_sample = i; /* In range 0..1 */
+      double output, error, encoded_sample, encoded_error;
+      double es_lo, es_hi;
+      int compose = 0;           /* Set to one if composition done */
+      int output_is_encoded;     /* Set if encoded to screen gamma */
+      int log_max_error = 1;     /* Check maximum error values */
+      png_const_charp pass = 0;  /* Reason test passes (or 0 for fail) */
+      /* Convert to linear light (with the above caveat.)  The alpha channel is
+       * already linear.
+       */
+      if (alpha >= 0)
+      {
+         int tcompose;
+         if (vi->file_inverse > 0)
+            input_sample = pow(input_sample, vi->file_inverse);
+         /* Handle the compose processing: */
+         tcompose = 0;
+         input_sample = gamma_component_compose(do_background, input_sample,
+            alpha, background, &tcompose);
+         if (tcompose)
+            compose = 1;
+      }
+      /* And similarly for the output value, but we need to check the background
+       * handling to linearize it correctly.
+       */
+      output = od;
+      output /= outmax;
+      output_is_encoded = vi->screen_gamma > 0;
+      if (alpha < 0) /* The alpha channel */
+      {
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+         if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
+#endif
+         {
+            /* In all other cases the output alpha channel is linear already,
+             * don't log errors here, they are much larger in linear data.
+             */
+            output_is_encoded = 0;
+            log_max_error = 0;
+         }
+      }
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      else /* A component */
+      {
+         if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
+            alpha < 1) /* the optimized case - linear output */
+         {
+            if (alpha > 0) log_max_error = 0;
+            output_is_encoded = 0;
+         }
+      }
+#endif
+      if (output_is_encoded)
+         output = pow(output, vi->screen_gamma);
+      /* Calculate (or recalculate) the encoded_sample value and repeat the
+       * check above (unnecessary if we took the fast route, but harmless.)
+       */
+      encoded_sample = input_sample;
+      if (output_is_encoded)
+         encoded_sample = pow(encoded_sample, vi->screen_inverse);
+      encoded_sample *= outmax;
+      encoded_error = fabs(od-encoded_sample);
+      /* Don't log errors in the alpha channel, or the 'optimized' case,
+       * neither are significant to the overall perception.
+       */
+      if (log_max_error && encoded_error > vi->dp->maxerrout)
+         vi->dp->maxerrout = encoded_error;
+      if (encoded_error < vi->maxout_total)
+      {
+         if (encoded_error < vi->outlog)
+            return i;
+         /* Test passed but error is bigger than the log limit, record why the
+          * test passed:
+          */
+         pass = "less than maxout:\n";
+      }
+      /* i: the original input value in the range 0..1
+       *
+       * pngvalid calculations:
+       *  input_sample: linear result; i linearized and composed, range 0..1
+       *  encoded_sample: encoded result; input_sample scaled to ouput bit depth
+       *
+       * libpng calculations:
+       *  output: linear result; od scaled to 0..1 and linearized
+       *  od: encoded result from libpng
+       */
+      /* Now we have the numbers for real errors, both absolute values as as a
+       * percentage of the correct value (output):
+       */
+      error = fabs(input_sample-output);
+      if (log_max_error && error > vi->dp->maxerrabs)
+         vi->dp->maxerrabs = error;
+      /* The following is an attempt to ignore the tendency of quantization to
+       * dominate the percentage errors for lower result values:
+       */
+      if (log_max_error && input_sample > .5)
+      {
+         double percentage_error = error/input_sample;
+         if (percentage_error > vi->dp->maxerrpc)
+            vi->dp->maxerrpc = percentage_error;
+      }
+      /* Now calculate the digitization limits for 'encoded_sample' using the
+       * 'max' values.  Note that maxout is in the encoded space but maxpc and
+       * maxabs are in linear light space.
+       *
+       * First find the maximum error in linear light space, range 0..1:
+       */
+      {
+         double tmp = input_sample * vi->maxpc;
+         if (tmp < vi->maxabs) tmp = vi->maxabs;
+         /* If 'compose' is true the composition was done in linear space using
+          * integer arithmetic.  This introduces an extra error of +/- 0.5 (at
+          * least) in the integer space used.  'maxcalc' records this, taking
+          * into account the possibility that even for 16 bit output 8 bit space
+          * may have been used.
+          */
+         if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
+         /* The 'maxout' value refers to the encoded result, to compare with
+          * this encode input_sample adjusted by the maximum error (tmp) above.
+          */
+         es_lo = encoded_sample - vi->maxout;
+         if (es_lo > 0 && input_sample-tmp > 0)
+         {
+            double low_value = input_sample-tmp;
+            if (output_is_encoded)
+               low_value = pow(low_value, vi->screen_inverse);
+            low_value *= outmax;
+            if (low_value < es_lo) es_lo = low_value;
+            /* Quantize this appropriately: */
+            es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
+         }
+         else
+            es_lo = 0;
+         es_hi = encoded_sample + vi->maxout;
+         if (es_hi < outmax && input_sample+tmp < 1)
+         {
+            double high_value = input_sample+tmp;
+            if (output_is_encoded)
+               high_value = pow(high_value, vi->screen_inverse);
+            high_value *= outmax;
+            if (high_value > es_hi) es_hi = high_value;
+            es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
+         }
+         else
+            es_hi = outmax;
+      }
+      /* The primary test is that the final encoded value returned by the
+       * library should be between the two limits (inclusive) that were
+       * calculated above.
+       */
+      if (od >= es_lo && od <= es_hi)
+      {
+         /* The value passes, but we may need to log the information anyway. */
+         if (encoded_error < vi->outlog)
+            return i;
+         if (pass == 0)
+            pass = "within digitization limits:\n";
+      }
+      {
+         /* There has been an error in processing, or we need to log this
+          * value.
+          */
+         double is_lo, is_hi;
+         /* pass is set at this point if either of the tests above would have
+          * passed.  Don't do these additional tests here - just log the
+          * original [es_lo..es_hi] values.
+          */
+         if (pass == 0 && vi->use_input_precision)
+         {
+            /* Ok, something is wrong - this actually happens in current libpng
+             * 16-to-8 processing.  Assume that the input value (id, adjusted
+             * for sbit) can be anywhere between value-.5 and value+.5 - quite a
+             * large range if sbit is low.
+             */
+            double tmp = (isbit - .5)/sbit_max;
+            if (tmp <= 0)
+               tmp = 0;
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+            is_lo = ceil(outmax * tmp - vi->maxout_total);
+            if (is_lo < 0)
+               is_lo = 0;
+            tmp = (isbit + .5)/sbit_max;
+            if (tmp <= 0)
+               tmp = 0;
+            else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+               tmp = pow(tmp, vi->file_inverse);
+            tmp = gamma_component_compose(do_background, tmp, alpha, background,
+               NULL);
+            if (output_is_encoded && tmp > 0 && tmp < 1)
+               tmp = pow(tmp, vi->screen_inverse);
+            is_hi = floor(outmax * tmp + vi->maxout_total);
+            if (is_hi > outmax)
+               is_hi = outmax;
+            if (!(od < is_lo || od > is_hi))
+            {
+               if (encoded_error < vi->outlog)
+                  return i;
+               pass = "within input precision limits:\n";
+            }
+            /* One last chance.  If this is an alpha channel and the 16to8
+             * option has been used and 'inaccurate' scaling is used then the
+             * bit reduction is obtained by simply using the top 8 bits of the
+             * value.
+             *
+             * This is only done for older libpng versions when the 'inaccurate'
+             * (chop) method of scaling was used.
+             */
+#           ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#              if PNG_LIBPNG_VER < 10504
+                  /* This may be required for other components in the future,
+                   * but at present the presence of gamma correction effectively
+                   * prevents the errors in the component scaling (I don't quite
+                   * understand why, but since it's better this way I care not
+                   * to ask, JB 20110419.)
+                   */
+                  if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
+                     vi->sbit + vi->isbit_shift == 16)
+                  {
+                     tmp = ((id >> 8) - .5)/255;
+                     if (tmp > 0)
+                     {
+                        is_lo = ceil(outmax * tmp - vi->maxout_total);
+                        if (is_lo < 0) is_lo = 0;
+                     }
+                     else
+                        is_lo = 0;
+                     tmp = ((id >> 8) + .5)/255;
+                     if (tmp < 1)
+                     {
+                        is_hi = floor(outmax * tmp + vi->maxout_total);
+                        if (is_hi > outmax) is_hi = outmax;
+                     }
+                     else
+                        is_hi = outmax;
+                     if (!(od < is_lo || od > is_hi))
+                     {
+                        if (encoded_error < vi->outlog)
+                           return i;
+                        pass = "within 8 bit limits:\n";
+                     }
+                  }
+#              endif
+#           endif
+         }
+         else /* !use_input_precision */
+            is_lo = es_lo, is_hi = es_hi;
+         /* Attempt to output a meaningful error/warning message: the message
+          * output depends on the background/composite operation being performed
+          * because this changes what parameters were actually used above.
+          */
+         {
+            size_t pos = 0;
+            /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
+             * places.  Just use outmax to work out which.
+             */
+            int precision = (outmax >= 1000 ? 6 : 3);
+            int use_input=1, use_background=0, do_compose=0;
+            char msg[256];
+            if (pass != 0)
+               pos = safecat(msg, sizeof msg, pos, "\n\t");
+            /* Set up the various flags, the output_is_encoded flag above
+             * is also used below.  do_compose is just a double check.
+             */
+            switch (do_background)
+            {
+            case PNG_BACKGROUND_GAMMA_SCREEN:
+            case PNG_BACKGROUND_GAMMA_FILE:
+            case PNG_BACKGROUND_GAMMA_UNIQUE:
+               use_background = (alpha >= 0 && alpha < 1);
+               /*FALL THROUGH*/
+#           ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+               case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+#           endif /* ALPHA_MODE_SUPPORTED */
+               do_compose = (alpha > 0 && alpha < 1);
+               use_input = (alpha != 0);
+               break;
+            default:
+               break;
+            }
+            /* Check the 'compose' flag */
+            if (compose != do_compose)
+               png_error(vi->pp, "internal error (compose)");
+            /* 'name' is the component name */
+            pos = safecat(msg, sizeof msg, pos, name);
+            pos = safecat(msg, sizeof msg, pos, "(");
+            pos = safecatn(msg, sizeof msg, pos, id);
+            if (use_input || pass != 0/*logging*/)
+            {
+               if (isbit != id)
+               {
+                  /* sBIT has reduced the precision of the input: */
+                  pos = safecat(msg, sizeof msg, pos, ", sbit(");
+                  pos = safecatn(msg, sizeof msg, pos, vi->sbit);
+                  pos = safecat(msg, sizeof msg, pos, "): ");
+                  pos = safecatn(msg, sizeof msg, pos, isbit);
+               }
+               pos = safecat(msg, sizeof msg, pos, "/");
+               /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
+               pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
+            }
+            pos = safecat(msg, sizeof msg, pos, ")");
+            /* A component may have been multiplied (in linear space) by the
+             * alpha value, 'compose' says whether this is relevant.
+             */
+            if (compose || pass != 0)
+            {
+               /* If any form of composition is being done report our
+                * calculated linear value here (the code above doesn't record
+                * the input value before composition is performed, so what
+                * gets reported is the value after composition.)
+                */
+               if (use_input || pass != 0)
+               {
+                  if (vi->file_inverse > 0)
+                  {
+                     pos = safecat(msg, sizeof msg, pos, "^");
+                     pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
+                  }
+                  else
+                     pos = safecat(msg, sizeof msg, pos, "[linear]");
+                  pos = safecat(msg, sizeof msg, pos, "*(alpha)");
+                  pos = safecatd(msg, sizeof msg, pos, alpha, precision);
+               }
+               /* Now record the *linear* background value if it was used
+                * (this function is not passed the original, non-linear,
+                * value but it is contained in the test name.)
+                */
+               if (use_background)
+               {
+                  pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
+                  pos = safecat(msg, sizeof msg, pos, "(background)");
+                  pos = safecatd(msg, sizeof msg, pos, background, precision);
+                  pos = safecat(msg, sizeof msg, pos, "*");
+                  pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
+               }
+            }
+            /* Report the calculated value (input_sample) and the linearized
+             * libpng value (output) unless this is just a component gamma
+             * correction.
+             */
+            if (compose || alpha < 0 || pass != 0)
+            {
+               pos = safecat(msg, sizeof msg, pos,
+                  pass != 0 ? " =\n\t" : " = ");
+               pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
+               pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+               pos = safecatd(msg, sizeof msg, pos, output, precision);
+               pos = safecat(msg, sizeof msg, pos, ")");
+               /* Finally report the output gamma encoding, if any. */
+               if (output_is_encoded)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(to screen) =");
+               }
+               else
+                  pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
+            }
+            if ((!compose && alpha >= 0) || pass != 0)
+            {
+               if (pass != 0) /* logging */
+                  pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
+               /* This is the non-composition case, the internal linear
+                * values are irrelevant (though the log below will reveal
+                * them.)  Output a much shorter warning/error message and report
+                * the overall gamma correction.
+                */
+               if (vi->gamma_correction > 0)
+               {
+                  pos = safecat(msg, sizeof msg, pos, " ^");
+                  pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
+                  pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
+               }
+               else
+                  pos = safecat(msg, sizeof msg, pos,
+                     " [no gamma correction] =");
+               if (pass != 0)
+                  pos = safecat(msg, sizeof msg, pos, "]");
+            }
+            /* This is our calculated encoded_sample which should (but does
+             * not) match od:
+             */
+            pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
+            pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
+            pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+            pos = safecatn(msg, sizeof msg, pos, od);
+            pos = safecat(msg, sizeof msg, pos, ")");
+            pos = safecat(msg, sizeof msg, pos, "/");
+            pos = safecatn(msg, sizeof msg, pos, outmax);
+            pos = safecat(msg, sizeof msg, pos, " < ");
+            pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
+            if (pass == 0) /* The error condition */
+            {
+#              ifdef PNG_WARNINGS_SUPPORTED
+                  png_warning(vi->pp, msg);
+#              else
+                  store_warning(vi->pp, msg);
+#              endif
+            }
+            else /* logging this value */
+               store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
+         }
+      }
+   }
+   return i;
+}
+static void
+gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi)
+{
+   /* Get some constants derived from the input and output file formats: */
+   PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
+   PNG_CONST png_byte in_ct = dp->this.colour_type;
+   PNG_CONST png_byte in_bd = dp->this.bit_depth;
+   PNG_CONST png_uint_32 w = dp->this.w;
+   PNG_CONST png_uint_32 h = dp->this.h;
+   PNG_CONST size_t cbRow = dp->this.cbRow;
+   PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
+   PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
+   /* There are three sources of error, firstly the quantization in the
+    * file encoding, determined by sbit and/or the file depth, secondly
+    * the output (screen) gamma and thirdly the output file encoding.
+    *
+    * Since this API receives the screen and file gamma in double
+    * precision it is possible to calculate an exact answer given an input
+    * pixel value.  Therefore we assume that the *input* value is exact -
+    * sample/maxsample - calculate the corresponding gamma corrected
+    * output to the limits of double precision arithmetic and compare with
+    * what libpng returns.
+    *
+    * Since the library must quantize the output to 8 or 16 bits there is
+    * a fundamental limit on the accuracy of the output of +/-.5 - this
+    * quantization limit is included in addition to the other limits
+    * specified by the paramaters to the API.  (Effectively, add .5
+    * everywhere.)
+    *
+    * The behavior of the 'sbit' paramter is defined by section 12.5
+    * (sample depth scaling) of the PNG spec.  That section forces the
+    * decoder to assume that the PNG values have been scaled if sBIT is
+    * present:
+    *
+    *     png-sample = floor( input-sample * (max-out/max-in) + .5);
+    *
+    * This means that only a subset of the possible PNG values should
+    * appear in the input. However, the spec allows the encoder to use a
+    * variety of approximations to the above and doesn't require any
+    * restriction of the values produced.
+    *
+    * Nevertheless the spec requires that the upper 'sBIT' bits of the
+    * value stored in a PNG file be the original sample bits.
+    * Consequently the code below simply scales the top sbit bits by
+    * (1<<sbit)-1 to obtain an original sample value.
+    *
+    * Because there is limited precision in the input it is arguable that
+    * an acceptable result is any valid result from input-.5 to input+.5.
+    * The basic tests below do not do this, however if 'use_input_precision'
+    * is set a subsequent test is performed below.
+    */
+   PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
+   int processing;
+   png_uint_32 y;
+   PNG_CONST store_palette_entry *in_palette = dp->this.palette;
+   PNG_CONST int in_is_transparent = dp->this.is_transparent;
+   int out_npalette = -1;
+   int out_is_transparent = 0; /* Just refers to the palette case */
+   store_palette out_palette;
+   validate_info vi;
+   /* Check for row overwrite errors */
+   store_image_check(dp->this.ps, pp, 0);
+   /* Supply the input and output sample depths here - 8 for an indexed image,
+    * otherwise the bit depth.
+    */
+   init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
+   processing = (vi.gamma_correction > 0 && !dp->threshold_test)
+      || in_bd != out_bd || in_ct != out_ct || vi.do_background;
+   /* TODO: FIX THIS: MAJOR BUG!  If the transformations all happen inside
+    * the palette there is no way of finding out, because libpng fails to
+    * update the palette on png_read_update_info.  Indeed, libpng doesn't
+    * even do the required work until much later, when it doesn't have any
+    * info pointer.  Oops.  For the moment 'processing' is turned off if
+    * out_ct is palette.
+    */
+   if (in_ct == 3 && out_ct == 3)
+      processing = 0;
+   if (processing && out_ct == 3)
+      out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
+   for (y=0; y<h; ++y)
+   {
+      png_const_bytep pRow = store_image_row(ps, pp, 0, y);
+      png_byte std[STANDARD_ROWMAX];
+      transform_row(pp, std, in_ct, in_bd, y);
+      if (processing)
+      {
+         unsigned int x;
+         for (x=0; x<w; ++x)
+         {
+            double alpha = 1; /* serves as a flag value */
+            /* Record the palette index for index images. */
+            PNG_CONST unsigned int in_index =
+               in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256;
+            PNG_CONST unsigned int out_index =
+               out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256;
+            /* Handle input alpha - png_set_background will cause the output
+             * alpha to disappear so there is nothing to check.
+             */
+            if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 &&
+               in_is_transparent))
+            {
+               PNG_CONST unsigned int input_alpha = in_ct == 3 ?
+                  dp->this.palette[in_index].alpha :
+                  sample(std, in_ct, in_bd, x, samples_per_pixel);
+               unsigned int output_alpha = 65536 /* as a flag value */;
+               if (out_ct == 3)
+               {
+                  if (out_is_transparent)
+                     output_alpha = out_palette[out_index].alpha;
+               }
+               else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
+                  output_alpha = sample(pRow, out_ct, out_bd, x,
+                     samples_per_pixel);
+               if (output_alpha != 65536)
+                  alpha = gamma_component_validate("alpha", &vi, input_alpha,
+                     output_alpha, -1/*alpha*/, 0/*background*/);
+               else /* no alpha in output */
+               {
+                  /* This is a copy of the calculation of 'i' above in order to
+                   * have the alpha value to use in the background calculation.
+                   */
+                  alpha = input_alpha >> vi.isbit_shift;
+                  alpha /= vi.sbit_max;
+               }
+            }
+            /* Handle grayscale or RGB components. */
+            if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
+               (void)gamma_component_validate("gray", &vi,
+                  sample(std, in_ct, in_bd, x, 0),
+                  sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/,
+                  vi.background_red);
+            else /* RGB or palette */
+            {
+               (void)gamma_component_validate("red", &vi,
+                  in_ct == 3 ? in_palette[in_index].red :
+                     sample(std, in_ct, in_bd, x, 0),
+                  out_ct == 3 ? out_palette[out_index].red :
+                     sample(pRow, out_ct, out_bd, x, 0),
+                  alpha/*component*/, vi.background_red);
+               (void)gamma_component_validate("green", &vi,
+                  in_ct == 3 ? in_palette[in_index].green :
+                     sample(std, in_ct, in_bd, x, 1),
+                  out_ct == 3 ? out_palette[out_index].green :
+                     sample(pRow, out_ct, out_bd, x, 1),
+                  alpha/*component*/, vi.background_green);
+               (void)gamma_component_validate("blue", &vi,
+                  in_ct == 3 ? in_palette[in_index].blue :
+                     sample(std, in_ct, in_bd, x, 2),
+                  out_ct == 3 ? out_palette[out_index].blue :
+                     sample(pRow, out_ct, out_bd, x, 2),
+                  alpha/*component*/, vi.background_blue);
+            }
+         }
+      }
+      else if (memcmp(std, pRow, cbRow) != 0)
+      {
+         char msg[64];
+         /* No transform is expected on the threshold tests. */
+         sprintf(msg, "gamma: below threshold row %d changed", y);
+         png_error(pp, msg);
+      }
+   } /* row (y) loop */
+   dp->this.ps->validated = 1;
+}
+static void
+gamma_end(png_structp pp, png_infop pi)
+{
+   gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
+   if (!dp->this.speed)
+      gamma_image_validate(dp, pp, pi);
+   else
+      dp->this.ps->validated = 1;
+}
+/* A single test run checking a gamma transformation.
+ *
+ * maxabs: maximum absolute error as a fraction
+ * maxout: maximum output error in the output units
+ * maxpc:  maximum percentage error (as a percentage)
+ */
+static void
+gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
+    PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn,
+    PNG_CONST int interlace_typeIn,
+    PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
+    PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
+    PNG_CONST char *name,
+    PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In,
+    PNG_CONST int expand16In, PNG_CONST int do_backgroundIn,
+    PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
+{
+   gamma_display d;
+   context(&pmIn->this, fault);
+   gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
+      palette_numberIn, interlace_typeIn, 0, 0, 0),
+      file_gammaIn, screen_gammaIn, sbitIn,
+      threshold_testIn, use_input_precisionIn, scale16In,
+      expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
+   Try
+   {
+      png_structp pp;
+      png_infop pi;
+      gama_modification gama_mod;
+      srgb_modification srgb_mod;
+      sbit_modification sbit_mod;
+      /* For the moment don't use the png_modifier support here. */
+      d.pm->encoding_counter = 0;
+      modifier_set_encoding(d.pm); /* Just resets everything */
+      d.pm->current_gamma = d.file_gamma;
+      /* Make an appropriate modifier to set the PNG file gamma to the
+       * given gamma value and the sBIT chunk to the given precision.
+       */
+      d.pm->modifications = NULL;
+      gama_modification_init(&gama_mod, d.pm, d.file_gamma);
+      srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
+      if (d.sbit > 0)
+         sbit_modification_init(&sbit_mod, d.pm, d.sbit);
+      modification_reset(d.pm->modifications);
+      /* Get a png_struct for writing the image. */
+      pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
+      standard_palette_init(&d.this);
+      /* Introduce the correct read function. */
+      if (d.pm->this.progressive)
+      {
+         /* Share the row function with the standard implementation. */
+         png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
+            gamma_end);
+         /* Now feed data into the reader until we reach the end: */
+         modifier_progressive_read(d.pm, pp, pi);
+      }
+      else
+      {
+         /* modifier_read expects a png_modifier* */
+         png_set_read_fn(pp, d.pm, modifier_read);
+         /* Check the header values: */
+         png_read_info(pp, pi);
+         /* Process the 'info' requirements. Only one image is generated */
+         gamma_info_imp(&d, pp, pi);
+         sequential_row(&d.this, pp, pi, -1, 0);
+         if (!d.this.speed)
+            gamma_image_validate(&d, pp, pi);
+         else
+            d.this.ps->validated = 1;
+      }
+      modifier_reset(d.pm);
+      if (d.pm->log && !d.threshold_test && !d.this.speed)
+         fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
+            d.this.bit_depth, colour_types[d.this.colour_type], name,
+            d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
+      /* Log the summary values too. */
+      if (d.this.colour_type == 0 || d.this.colour_type == 4)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 1:
+            break;
+         case 2:
+            if (d.maxerrout > d.pm->error_gray_2)
+               d.pm->error_gray_2 = d.maxerrout;
+            break;
+         case 4:
+            if (d.maxerrout > d.pm->error_gray_4)
+               d.pm->error_gray_4 = d.maxerrout;
+            break;
+         case 8:
+            if (d.maxerrout > d.pm->error_gray_8)
+               d.pm->error_gray_8 = d.maxerrout;
+            break;
+         case 16:
+            if (d.maxerrout > d.pm->error_gray_16)
+               d.pm->error_gray_16 = d.maxerrout;
+            break;
+         default:
+            png_error(pp, "bad bit depth (internal: 1)");
+         }
+      }
+      else if (d.this.colour_type == 2 || d.this.colour_type == 6)
+      {
+         switch (d.this.bit_depth)
+         {
+         case 8:
+            if (d.maxerrout > d.pm->error_color_8)
+               d.pm->error_color_8 = d.maxerrout;
+            break;
+         case 16:
+            if (d.maxerrout > d.pm->error_color_16)
+               d.pm->error_color_16 = d.maxerrout;
+            break;
+         default:
+            png_error(pp, "bad bit depth (internal: 2)");
+         }
+      }
+      else if (d.this.colour_type == 3)
+      {
+         if (d.maxerrout > d.pm->error_indexed)
+            d.pm->error_indexed = d.maxerrout;
+      }
+   }
+   Catch(fault)
+      modifier_reset((png_modifier*)fault);
+}
+static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
+    png_byte bit_depth, int interlace_type, double file_gamma,
+    double screen_gamma)
+{
+   size_t pos = 0;
+   char name[64];
+   pos = safecat(name, sizeof name, pos, "threshold ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "/");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+   (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
+      0 /*no input precision*/,
+      0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
+      0 /*no background gamma*/);
+}
+static void
+perform_gamma_threshold_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   int palette_number = 0;
+   /* Don't test more than one instance of each palette - it's pointless, in
+    * fact this test is somewhat excessive since libpng doesn't make this
+    * decision based on colour type or bit depth!
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number))
+      if (palette_number == 0)
+   {
+      double test_gamma = 1.0;
+      while (test_gamma >= .4)
+      {
+         /* There's little point testing the interlacing vs non-interlacing,
+          * but this can be set from the command line.
+          */
+         gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+            test_gamma, 1/test_gamma);
+         test_gamma *= .95;
+      }
+      /* And a special test for sRGB */
+      gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+          .45455, 2.2);
+      if (fail(pm))
+         return;
+   }
+}
+static void gamma_transform_test(png_modifier *pm,
+   PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
+   PNG_CONST int palette_number,
+   PNG_CONST int interlace_type, PNG_CONST double file_gamma,
+   PNG_CONST double screen_gamma, PNG_CONST png_byte sbit,
+   PNG_CONST int use_input_precision, PNG_CONST int scale16)
+{
+   size_t pos = 0;
+   char name[64];
+   if (sbit != bit_depth && sbit != 0)
+   {
+      pos = safecat(name, sizeof name, pos, "sbit(");
+      pos = safecatn(name, sizeof name, pos, sbit);
+      pos = safecat(name, sizeof name, pos, ") ");
+   }
+   else
+      pos = safecat(name, sizeof name, pos, "gamma ");
+   if (scale16)
+      pos = safecat(name, sizeof name, pos, "16to8 ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
+      scale16, pm->test_gamma_expand16, 0 , 0, 0);
+}
+static void perform_gamma_transform_tests(png_modifier *pm)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   int palette_number = 0;
+   while (next_format(&colour_type, &bit_depth, &palette_number))
+   {
+      unsigned int i, j;
+      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+         if (i != j)
+         {
+            gamma_transform_test(pm, colour_type, bit_depth, palette_number,
+               pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
+               pm->use_input_precision, 0 /*do not scale16*/);
+            if (fail(pm))
+               return;
+         }
+   }
+}
+static void perform_gamma_sbit_tests(png_modifier *pm)
+{
+   png_byte sbit;
+   /* The only interesting cases are colour and grayscale, alpha is ignored here
+    * for overall speed.  Only bit depths where sbit is less than the bit depth
+    * are tested.
+    */
+   for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
+   {
+      png_byte colour_type, bit_depth;
+      int npalette;
+      colour_type = bit_depth = 0;
+      npalette = 0;
+      while (next_format(&colour_type, &bit_depth, &npalette))
+         if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
+            ((colour_type == 3 && sbit < 8) ||
+            (colour_type != 3 && sbit < bit_depth)))
+      {
+         unsigned int i;
+         for (i=0; i<pm->ngamma_tests; ++i)
+         {
+            unsigned int j;
+            for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
+            {
+               gamma_transform_test(pm, colour_type, bit_depth, npalette,
+                  pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+                  sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
+               if (fail(pm))
+                  return;
+            }
+         }
+      }
+   }
+}
+/* Note that this requires a 16 bit source image but produces 8 bit output, so
+ * we only need the 16bit write support, but the 16 bit images are only
+ * generated if DO_16BIT is defined.
+ */
+#ifdef DO_16BIT
+static void perform_gamma_scale16_tests(png_modifier *pm)
+{
+#  ifndef PNG_MAX_GAMMA_8
+#     define PNG_MAX_GAMMA_8 11
+#  endif
+   /* Include the alpha cases here. Note that sbit matches the internal value
+    * used by the library - otherwise we will get spurious errors from the
+    * internal sbit style approximation.
+    *
+    * The threshold test is here because otherwise the 16 to 8 conversion will
+    * proceed *without* gamma correction, and the tests above will fail (but not
+    * by much) - this could be fixed, it only appears with the -g option.
+    */
+   unsigned int i, j;
+   for (i=0; i<pm->ngamma_tests; ++i)
+   {
+      for (j=0; j<pm->ngamma_tests; ++j)
+      {
+         if (i != j &&
+             fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
+         {
+            gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+            if (fail(pm))
+               return;
+            gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+            if (fail(pm))
+               return;
+            gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+            if (fail(pm))
+               return;
+            gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
+               1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+               pm->use_input_precision_16to8, 1 /*scale16*/);
+            if (fail(pm))
+               return;
+         }
+      }
+   }
+}
+#endif /* 16 to 8 bit conversion */
+#if defined PNG_READ_BACKGROUND_SUPPORTED ||\
+   defined PNG_READ_ALPHA_MODE_SUPPORTED
+static void gamma_composition_test(png_modifier *pm,
+   PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
+   PNG_CONST int palette_number,
+   PNG_CONST int interlace_type, PNG_CONST double file_gamma,
+   PNG_CONST double screen_gamma,
+   PNG_CONST int use_input_precision, PNG_CONST int do_background,
+   PNG_CONST int expand_16)
+{
+   size_t pos = 0;
+   png_const_charp base;
+   double bg;
+   char name[128];
+   png_color_16 background;
+   /* Make up a name and get an appropriate background gamma value. */
+   switch (do_background)
+   {
+      default:
+         base = "";
+         bg = 4; /* should not be used */
+         break;
+      case PNG_BACKGROUND_GAMMA_SCREEN:
+         base = " bckg(Screen):";
+         bg = 1/screen_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_FILE:
+         base = " bckg(File):";
+         bg = file_gamma;
+         break;
+      case PNG_BACKGROUND_GAMMA_UNIQUE:
+         base = " bckg(Unique):";
+         /* This tests the handling of a unique value, the math is such that the
+          * value tends to be <1, but is neither screen nor file (even if they
+          * match!)
+          */
+         bg = (file_gamma + screen_gamma) / 3;
+         break;
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
+         base = " alpha(PNG)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+         base = " alpha(Porter-Duff)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+         base = " alpha(Optimized)";
+         bg = 4; /* should not be used */
+         break;
+      case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+         base = " alpha(Broken)";
+         bg = 4; /* should not be used */
+         break;
+#endif
+   }
+   /* Use random background values - the background is always presented in the
+    * output space (8 or 16 bit components).
+    */
+   if (expand_16 || bit_depth == 16)
+   {
+      png_uint_32 r = random_32();
+      background.red = (png_uint_16)r;
+      background.green = (png_uint_16)(r >> 16);
+      r = random_32();
+      background.blue = (png_uint_16)r;
+      background.gray = (png_uint_16)(r >> 16);
+   }
+   else /* 8 bit colors */
+   {
+      png_uint_32 r = random_32();
+      background.red = (png_byte)r;
+      background.green = (png_byte)(r >> 8);
+      background.blue = (png_byte)(r >> 16);
+      background.gray = (png_byte)(r >> 24);
+   }
+   background.index = 193; /* rgb(193,193,193) to detect errors */
+   if (!(colour_type & PNG_COLOR_MASK_COLOR))
+   {
+      /* Grayscale input, we do not convert to RGB (TBD), so we must set the
+       * background to gray - else libpng seems to fail.
+       */
+      background.red = background.green = background.blue = background.gray;
+   }
+   pos = safecat(name, sizeof name, pos, "gamma ");
+   pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+   pos = safecat(name, sizeof name, pos, "->");
+   pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+   pos = safecat(name, sizeof name, pos, base);
+   if (do_background < ALPHA_MODE_OFFSET)
+   {
+      /* Include the background color and gamma in the name: */
+      pos = safecat(name, sizeof name, pos, "(");
+      /* This assumes no expand gray->rgb - the current code won't handle that!
+       */
+      if (colour_type & PNG_COLOR_MASK_COLOR)
+      {
+         pos = safecatn(name, sizeof name, pos, background.red);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.green);
+         pos = safecat(name, sizeof name, pos, ",");
+         pos = safecatn(name, sizeof name, pos, background.blue);
+      }
+      else
+         pos = safecatn(name, sizeof name, pos, background.gray);
+      pos = safecat(name, sizeof name, pos, ")^");
+      pos = safecatd(name, sizeof name, pos, bg, 3);
+   }
+   gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+      file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
+      0/*strip 16*/, expand_16, do_background, &background, bg);
+}
+static void
+perform_gamma_composition_tests(png_modifier *pm, int do_background,
+   int expand_16)
+{
+   png_byte colour_type = 0;
+   png_byte bit_depth = 0;
+   int palette_number = 0;
+   /* Skip the non-alpha cases - there is no setting of a transparency colour at
+    * present.
+    */
+   while (next_format(&colour_type, &bit_depth, &palette_number))
+      if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0)
+   {
+      unsigned int i, j;
+      /* Don't skip the i==j case here - it's relevant. */
+      for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+      {
+         gamma_composition_test(pm, colour_type, bit_depth, palette_number,
+            pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+            pm->use_input_precision, do_background, expand_16);
+         if (fail(pm))
+            return;
+      }
+   }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+static void
+init_gamma_errors(png_modifier *pm)
+{
+   pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+   pm->error_color_8 = 0;
+   pm->error_indexed = 0;
+   pm->error_gray_16 = pm->error_color_16 = 0;
+}
+static void
+summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth)
+{
+   if (who)
+      printf("Gamma correction with %s:\n", who);
+   if (low_bit_depth)
+   {
+      printf("  2 bit gray:  %.5f\n", pm->error_gray_2);
+      printf("  4 bit gray:  %.5f\n", pm->error_gray_4);
+      printf("  8 bit gray:  %.5f\n", pm->error_gray_8);
+      printf("  8 bit color: %.5f\n", pm->error_color_8);
+      printf("  indexed:     %.5f\n", pm->error_indexed);
+   }
+#ifdef DO_16BIT
+   printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
+   printf(" 16 bit color: %.5f\n", pm->error_color_16);
+#endif
+}
+static void
+perform_gamma_test(png_modifier *pm, int summary)
+{
+   /*TODO: remove this*/
+   /* Save certain values for the temporary overrides below. */
+   unsigned int calculations_use_input_precision =
+      pm->calculations_use_input_precision;
+   double maxout8 = pm->maxout8;
+   /* First some arbitrary no-transform tests: */
+   if (!pm->this.speed && pm->test_gamma_threshold)
+   {
+      perform_gamma_threshold_tests(pm);
+      if (fail(pm))
+         return;
+   }
+   /* Now some real transforms. */
+   if (pm->test_gamma_transform)
+   {
+      init_gamma_errors(pm);
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      perform_gamma_transform_tests(pm);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+      if (summary)
+      {
+         printf("Gamma correction error summary\n\n");
+         printf("The printed value is the maximum error in the pixel values\n");
+         printf("calculated by the libpng gamma correction code.  The error\n");
+         printf("is calculated as the difference between the output pixel\n");
+         printf("value (always an integer) and the ideal value from the\n");
+         printf("libpng specification (typically not an integer).\n\n");
+         printf("Expect this value to be less than .5 for 8 bit formats,\n");
+         printf("less than 1 for formats with fewer than 8 bits and a small\n");
+         printf("number (typically less than 5) for the 16 bit formats.\n");
+         printf("For performance reasons the value for 16 bit formats\n");
+         printf("increases when the image file includes an sBIT chunk.\n\n");
+         summarize_gamma_errors(pm, 0/*who*/, 1);
+      }
+   }
+   /* The sbit tests produce much larger errors: */
+   if (pm->test_gamma_sbit)
+   {
+      init_gamma_errors(pm);
+      perform_gamma_sbit_tests(pm);
+      if (summary)
+         summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U);
+   }
+#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
+   if (pm->test_gamma_scale16)
+   {
+      /* The 16 to 8 bit strip operations: */
+      init_gamma_errors(pm);
+      perform_gamma_scale16_tests(pm);
+      if (summary)
+      {
+         printf("Gamma correction with 16 to 8 bit reduction:\n");
+         printf(" 16 bit gray:  %.5f\n", pm->error_gray_16);
+         printf(" 16 bit color: %.5f\n", pm->error_color_16);
+      }
+   }
+#endif
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+   if (pm->test_gamma_background)
+   {
+      init_gamma_errors(pm);
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+      {
+         pm->calculations_use_input_precision = 1;
+         pm->maxout8 = .499; /* because the 16 bit background is smashed */
+      }
+      perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
+         pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+      pm->maxout8 = maxout8;
+      if (summary)
+         summarize_gamma_errors(pm, "background", 1);
+   }
+#endif
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+   if (pm->test_gamma_alpha_mode)
+   {
+      int do_background;
+      init_gamma_errors(pm);
+      /*TODO: remove this.  Necessary because the current libpng
+       * implementation works in 8 bits:
+       */
+      if (pm->test_gamma_expand16)
+         pm->calculations_use_input_precision = 1;
+      for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
+         do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
+         ++do_background)
+         perform_gamma_composition_tests(pm, do_background,
+            pm->test_gamma_expand16);
+      if (!calculations_use_input_precision)
+         pm->calculations_use_input_precision = 0;
+      if (summary)
+         summarize_gamma_errors(pm, "alpha mode", 1);
+   }
+#endif
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+/* INTERLACE MACRO VALIDATION */
+/* This is copied verbatim from the specification, it is simply the pass
+ * number in which each pixel in each 8x8 tile appears.  The array must
+ * be indexed adam7[y][x] and notice that the pass numbers are based at
+ * 1, not 0 - the base libpng uses.
+ */
+static PNG_CONST
+png_byte adam7[8][8] =
+{
+   { 1,6,4,6,2,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 3,6,4,6,3,6,4,6 },
+   { 7,7,7,7,7,7,7,7 },
+   { 5,6,5,6,5,6,5,6 },
+   { 7,7,7,7,7,7,7,7 }
+};
+/* This routine validates all the interlace support macros in png.h for
+ * a variety of valid PNG widths and heights.  It uses a number of similarly
+ * named internal routines that feed off the above array.
+ */
+static png_uint_32
+png_pass_start_row(int pass)
+{
+   int x, y;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+      return y;
+   return 0xf;
+}
+static png_uint_32
+png_pass_start_col(int pass)
+{
+   int x, y;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+      return x;
+   return 0xf;
+}
+static int
+png_pass_row_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+   {
+      if (base == (-1))
+         base = y;
+      else if (base == y)
+         {}
+      else if (inc == y-base)
+         base=y;
+      else if (inc == 8)
+         inc = y-base, base=y;
+      else if (inc != y-base)
+         return 0xff; /* error - more than one 'inc' value! */
+   }
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+static int
+png_pass_col_shift(int pass)
+{
+   int x, y, base=(-1), inc=8;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+   {
+      if (base == (-1))
+         base = x;
+      else if (base == x)
+         {}
+      else if (inc == x-base)
+         base=x;
+      else if (inc == 8)
+         inc = x-base, base=x;
+      else if (inc != x-base)
+         return 0xff; /* error - more than one 'inc' value! */
+   }
+   if (base == (-1)) return 0xfe; /* error - no row in pass! */
+   /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+   switch (inc)
+   {
+case 1: return 0; /* pass 7 has all the columns */
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+   }
+   /* error - unrecognized 'inc' */
+   return (inc << 8) + 0xfd;
+}
+static png_uint_32
+png_row_from_pass_row(png_uint_32 yIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return yIn * 8;
+case 1: return yIn * 8;
+case 2: return yIn * 8 + 4;
+case 3: return yIn * 4;
+case 4: return yIn * 4 + 2;
+case 5: return yIn * 2;
+case 6: return yIn * 2 + 1;
+default: break;
+   }
+   return 0xff; /* bad pass number */
+}
+static png_uint_32
+png_col_from_pass_col(png_uint_32 xIn, int pass)
+{
+   /* By examination of the array: */
+   switch (pass)
+   {
+case 0: return xIn * 8;
+case 1: return xIn * 8 + 4;
+case 2: return xIn * 4;
+case 3: return xIn * 4 + 2;
+case 4: return xIn * 2;
+case 5: return xIn * 2 + 1;
+case 6: return xIn;
+default: break;
+   }
+   return 0xff; /* bad pass number */
+}
+static int
+png_row_in_interlace_pass(png_uint_32 y, int pass)
+{
+   /* Is row 'y' in pass 'pass'? */
+   int x;
+   y &= 7;
+   ++pass;
+   for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+      return 1;
+   return 0;
+}
+static int
+png_col_in_interlace_pass(png_uint_32 x, int pass)
+{
+   /* Is column 'x' in pass 'pass'? */
+   int y;
+   x &= 7;
+   ++pass;
+   for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+      return 1;
+   return 0;
+}
+static png_uint_32
+png_pass_rows(png_uint_32 height, int pass)
+{
+   png_uint_32 tiles = height>>3;
+   png_uint_32 rows = 0;
+   unsigned int x, y;
+   height &= 7;
+   ++pass;
+   for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+   {
+      rows += tiles;
+      if (y < height) ++rows;
+      break; /* i.e. break the 'x', column, loop. */
+   }
+   return rows;
+}
+static png_uint_32
+png_pass_cols(png_uint_32 width, int pass)
+{
+   png_uint_32 tiles = width>>3;
+   png_uint_32 cols = 0;
+   unsigned int x, y;
+   width &= 7;
+   ++pass;
+   for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+   {
+      cols += tiles;
+      if (x < width) ++cols;
+      break; /* i.e. break the 'y', row, loop. */
+   }
+   return cols;
+}
+static void
+perform_interlace_macro_validation(void)
+{
+   /* The macros to validate, first those that depend only on pass:
+    *
+    * PNG_PASS_START_ROW(pass)
+    * PNG_PASS_START_COL(pass)
+    * PNG_PASS_ROW_SHIFT(pass)
+    * PNG_PASS_COL_SHIFT(pass)
+    */
+   int pass;
+   for (pass=0; pass<7; ++pass)
+   {
+      png_uint_32 m, f, v;
+      m = PNG_PASS_START_ROW(pass);
+      f = png_pass_start_row(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
+         exit(1);
+      }
+      m = PNG_PASS_START_COL(pass);
+      f = png_pass_start_col(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
+         exit(1);
+      }
+      m = PNG_PASS_ROW_SHIFT(pass);
+      f = png_pass_row_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(1);
+      }
+      m = PNG_PASS_COL_SHIFT(pass);
+      f = png_pass_col_shift(pass);
+      if (m != f)
+      {
+         fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
+         exit(1);
+      }
+      /* Macros that depend on the image or sub-image height too:
+       *
+       * PNG_PASS_ROWS(height, pass)
+       * PNG_PASS_COLS(width, pass)
+       * PNG_ROW_FROM_PASS_ROW(yIn, pass)
+       * PNG_COL_FROM_PASS_COL(xIn, pass)
+       * PNG_ROW_IN_INTERLACE_PASS(y, pass)
+       * PNG_COL_IN_INTERLACE_PASS(x, pass)
+       */
+      for (v=0;;)
+      {
+         /* First the base 0 stuff: */
+         m = PNG_ROW_FROM_PASS_ROW(v, pass);
+         f = png_row_from_pass_row(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         m = PNG_COL_FROM_PASS_COL(v, pass);
+         f = png_col_from_pass_col(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
+         f = png_row_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         m = PNG_COL_IN_INTERLACE_PASS(v, pass);
+         f = png_col_in_interlace_pass(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         /* Then the base 1 stuff: */
+         ++v;
+         m = PNG_PASS_ROWS(v, pass);
+         f = png_pass_rows(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         m = PNG_PASS_COLS(v, pass);
+         f = png_pass_cols(v, pass);
+         if (m != f)
+         {
+            fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
+               v, pass, m, f);
+            exit(1);
+         }
+         /* Move to the next v - the stepping algorithm starts skipping
+          * values above 1024.
+          */
+         if (v > 1024)
+         {
+            if (v == PNG_UINT_31_MAX)
+               break;
+            v = (v << 1) ^ v;
+            if (v >= PNG_UINT_31_MAX)
+               v = PNG_UINT_31_MAX-1;
+         }
+      }
+   }
+}
+/* Test color encodings. These values are back-calculated from the published
+ * chromaticities.  The values are accurate to about 14 decimal places; 15 are
+ * given.  These values are much more accurate than the ones given in the spec,
+ * which typically don't exceed 4 decimal places.  This allows testing of the
+ * libpng code to its theoretical accuracy of 4 decimal places.  (If pngvalid
+ * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
+ * more.)
+ *
+ * The png_modifier code assumes that encodings[0] is sRGB and treats it
+ * specially: do not change the first entry in this list!
+ */
+static PNG_CONST color_encoding test_encodings[] =
+{
+/* sRGB: must be first in this list! */
+/*gamma:*/ { 1/2.2,
+/*red:  */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
+/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
+/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
+/* Kodak ProPhoto (wide gamut) */
+/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
+/*red:  */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
+/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
+/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
+/* Adobe RGB (1998) */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
+/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
+/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
+/* Adobe Wide Gamut RGB */
+/*gamma:*/ { 1/(2+51./256),
+/*red:  */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
+};
+/* signal handler
+ *
+ * This attempts to trap signals and escape without crashing.  It needs a
+ * context pointer so that it can throw an exception (call longjmp) to recover
+ * from the condition; this is handled by making the png_modifier used by 'main'
+ * into a global variable.
+ */
+static png_modifier pm;
+static void signal_handler(int signum)
+{
+   size_t pos = 0;
+   char msg[64];
+   pos = safecat(msg, sizeof msg, pos, "caught signal: ");
+   switch (signum)
+   {
+      case SIGABRT:
+         pos = safecat(msg, sizeof msg, pos, "abort");
+         break;
+      case SIGFPE:
+         pos = safecat(msg, sizeof msg, pos, "floating point exception");
+         break;
+      case SIGILL:
+         pos = safecat(msg, sizeof msg, pos, "illegal instruction");
+         break;
+      case SIGINT:
+         pos = safecat(msg, sizeof msg, pos, "interrupt");
+         break;
+      case SIGSEGV:
+         pos = safecat(msg, sizeof msg, pos, "invalid memory access");
+         break;
+      case SIGTERM:
+         pos = safecat(msg, sizeof msg, pos, "termination request");
+         break;
+      default:
+         pos = safecat(msg, sizeof msg, pos, "unknown ");
+         pos = safecatn(msg, sizeof msg, pos, signum);
+         break;
+   }
+   store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
+   /* And finally throw an exception so we can keep going, unless this is
+    * SIGTERM in which case stop now.
+    */
+   if (signum != SIGTERM)
+   {
+      struct exception_context *the_exception_context =
+         &pm.this.exception_context;
+      Throw &pm.this;
+   }
+   else
+      exit(1);
+}
+/* main program */
+int main(int argc, PNG_CONST char **argv)
+{
+   volatile int summary = 1;  /* Print the error summary at the end */
+   volatile int memstats = 0; /* Print memory statistics at the end */
+   /* Create the given output file on success: */
+   PNG_CONST char *volatile touch = NULL;
+   /* This is an array of standard gamma values (believe it or not I've seen
+    * every one of these mentioned somewhere.)
+    *
+    * In the following list the most useful values are first!
+    */
+   static double
+      gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
+   /* This records the command and arguments: */
+   size_t cp = 0;
+   char command[1024];
+   anon_context(&pm.this);
+   /* Add appropriate signal handlers, just the ANSI specified ones: */
+   signal(SIGABRT, signal_handler);
+   signal(SIGFPE, signal_handler);
+   signal(SIGILL, signal_handler);
+   signal(SIGINT, signal_handler);
+   signal(SIGSEGV, signal_handler);
+   signal(SIGTERM, signal_handler);
+#ifdef HAVE_FEENABLEEXCEPT
+   /* Only required to enable FP exceptions on platforms where they start off
+    * disabled; this is not necessary but if it is not done pngvalid will likely
+    * end up ignoring FP conditions that other platforms fault.
+    */
+   feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
+#endif
+   modifier_init(&pm);
+   /* Preallocate the image buffer, because we know how big it needs to be,
+    * note that, for testing purposes, it is deliberately mis-aligned by tag
+    * bytes either side.  All rows have an additional five bytes of padding for
+    * overwrite checking.
+    */
+   store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
+   /* Don't give argv[0], it's normally some horrible libtool string: */
+   cp = safecat(command, sizeof command, cp, "pngvalid");
+   /* Default to error on warning: */
+   pm.this.treat_warnings_as_errors = 1;
+   /* Store the test gammas */
+   pm.gammas = gammas;
+   pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
+   pm.ngamma_tests = 0; /* default to off */
+   /* And the test encodings */
+   pm.encodings = test_encodings;
+   pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
+   pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
+   /* The following allows results to pass if they correspond to anything in the
+    * transformed range [input-.5,input+.5]; this is is required because of the
+    * way libpng treates the 16_TO_8 flag when building the gamma tables.
+    *
+    * TODO: review this
+    */
+   pm.use_input_precision_16to8 = 1U;
+   /* Some default values (set the behavior for 'make check' here).
+    * These values simply control the maximum error permitted in the gamma
+    * transformations.  The practial limits for human perception are described
+    * below (the setting for maxpc16), however for 8 bit encodings it isn't
+    * possible to meet the accepted capabilities of human vision - i.e. 8 bit
+    * images can never be good enough, regardless of encoding.
+    */
+   pm.maxout8 = .1;     /* Arithmetic error in *encoded* value */
+   pm.maxabs8 = .00005; /* 1/20000 */
+   pm.maxcalc8 = .004;  /* +/-1 in 8 bits for compose errors */
+   pm.maxpc8 = .499;    /* I.e., .499% fractional error */
+   pm.maxout16 = .499;  /* Error in *encoded* value */
+   pm.maxabs16 = .00005;/* 1/20000 */
+   pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */
+   /* NOTE: this is a reasonable perceptual limit. We assume that humans can
+    * perceive light level differences of 1% over a 100:1 range, so we need to
+    * maintain 1 in 10000 accuracy (in linear light space), which is what the
+    * following guarantees.  It also allows significantly higher errors at
+    * higher 16 bit values, which is important for performance.  The actual
+    * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
+    * this is only allowed for values >38149 by the following:
+    */
+   pm.maxpc16 = .005;   /* I.e., 1/200% - 1/20000 */
+   /* Now parse the command line options. */
+   while (--argc >= 1)
+   {
+      int catmore = 0; /* Set if the argument has an argument. */
+      /* Record each argument for posterity: */
+      cp = safecat(command, sizeof command, cp, " ");
+      cp = safecat(command, sizeof command, cp, *++argv);
+      if (strcmp(*argv, "-v") == 0)
+         pm.this.verbose = 1;
+      else if (strcmp(*argv, "-l") == 0)
+         pm.log = 1;
+      else if (strcmp(*argv, "-q") == 0)
+         summary = pm.this.verbose = pm.log = 0;
+      else if (strcmp(*argv, "-w") == 0)
+         pm.this.treat_warnings_as_errors = 0;
+      else if (strcmp(*argv, "--speed") == 0)
+         pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
+            summary = 0;
+      else if (strcmp(*argv, "--memory") == 0)
+         memstats = 1;
+      else if (strcmp(*argv, "--size") == 0)
+         pm.test_size = 1;
+      else if (strcmp(*argv, "--nosize") == 0)
+         pm.test_size = 0;
+      else if (strcmp(*argv, "--standard") == 0)
+         pm.test_standard = 1;
+      else if (strcmp(*argv, "--nostandard") == 0)
+         pm.test_standard = 0;
+      else if (strcmp(*argv, "--transform") == 0)
+         pm.test_transform = 1;
+      else if (strcmp(*argv, "--notransform") == 0)
+         pm.test_transform = 0;
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      else if (strncmp(*argv, "--transform-disable=",
+         sizeof "--transform-disable") == 0)
+         {
+         pm.test_transform = 1;
+         transform_disable(*argv + sizeof "--transform-disable");
+         }
+      else if (strncmp(*argv, "--transform-enable=",
+         sizeof "--transform-enable") == 0)
+         {
+         pm.test_transform = 1;
+         transform_enable(*argv + sizeof "--transform-enable");
+         }
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+      else if (strcmp(*argv, "--gamma") == 0)
+         {
+         /* Just do two gamma tests here (2.2 and linear) for speed: */
+         pm.ngamma_tests = 2U;
+         pm.test_gamma_threshold = 1;
+         pm.test_gamma_transform = 1;
+         pm.test_gamma_sbit = 1;
+         pm.test_gamma_scale16 = 1;
+         pm.test_gamma_background = 1;
+         pm.test_gamma_alpha_mode = 1;
+         }
+      else if (strcmp(*argv, "--nogamma") == 0)
+         pm.ngamma_tests = 0;
+      else if (strcmp(*argv, "--gamma-threshold") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
+      else if (strcmp(*argv, "--nogamma-threshold") == 0)
+         pm.test_gamma_threshold = 0;
+      else if (strcmp(*argv, "--gamma-transform") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
+      else if (strcmp(*argv, "--nogamma-transform") == 0)
+         pm.test_gamma_transform = 0;
+      else if (strcmp(*argv, "--gamma-sbit") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
+      else if (strcmp(*argv, "--nogamma-sbit") == 0)
+         pm.test_gamma_sbit = 0;
+      else if (strcmp(*argv, "--gamma-16-to-8") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
+      else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
+         pm.test_gamma_scale16 = 0;
+      else if (strcmp(*argv, "--gamma-background") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
+      else if (strcmp(*argv, "--nogamma-background") == 0)
+         pm.test_gamma_background = 0;
+      else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
+         pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
+      else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
+         pm.test_gamma_alpha_mode = 0;
+      else if (strcmp(*argv, "--expand16") == 0)
+         pm.test_gamma_expand16 = 1;
+      else if (strcmp(*argv, "--noexpand16") == 0)
+         pm.test_gamma_expand16 = 0;
+      else if (strcmp(*argv, "--more-gammas") == 0)
+         pm.ngamma_tests = 3U;
+      else if (strcmp(*argv, "--all-gammas") == 0)
+         pm.ngamma_tests = pm.ngammas;
+      else if (strcmp(*argv, "--progressive-read") == 0)
+         pm.this.progressive = 1;
+      else if (strcmp(*argv, "--use-update-info") == 0)
+         ++pm.use_update_info; /* Can call multiple times */
+      else if (strcmp(*argv, "--interlace") == 0)
+         pm.interlace_type = PNG_INTERLACE_ADAM7;
+      else if (strcmp(*argv, "--use-input-precision") == 0)
+         pm.use_input_precision = 1;
+      else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
+         pm.calculations_use_input_precision = 1;
+      else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
+         pm.assume_16_bit_calculations = 1;
+      else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
+         pm.calculations_use_input_precision =
+            pm.assume_16_bit_calculations = 0;
+      else if (strcmp(*argv, "--exhaustive") == 0)
+         pm.test_exhaustive = 1;
+      else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
+         --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
+      else if (argc > 1 && strcmp(*argv, "--touch") == 0)
+         --argc, touch = *++argv, catmore = 1;
+      else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
+      {
+         --argc;
+         if (strcmp(5+*argv, "abs8") == 0)
+            pm.maxabs8 = atof(*++argv);
+         else if (strcmp(5+*argv, "abs16") == 0)
+            pm.maxabs16 = atof(*++argv);
+         else if (strcmp(5+*argv, "calc8") == 0)
+            pm.maxcalc8 = atof(*++argv);
+         else if (strcmp(5+*argv, "calc16") == 0)
+            pm.maxcalc16 = atof(*++argv);
+         else if (strcmp(5+*argv, "out8") == 0)
+            pm.maxout8 = atof(*++argv);
+         else if (strcmp(5+*argv, "out16") == 0)
+            pm.maxout16 = atof(*++argv);
+         else if (strcmp(5+*argv, "pc8") == 0)
+            pm.maxpc8 = atof(*++argv);
+         else if (strcmp(5+*argv, "pc16") == 0)
+            pm.maxpc16 = atof(*++argv);
+         else
+         {
+            fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
+            exit(1);
+         }
+         catmore = 1;
+      }
+      else if (strcmp(*argv, "--log8") == 0)
+         --argc, pm.log8 = atof(*++argv), catmore = 1;
+      else if (strcmp(*argv, "--log16") == 0)
+         --argc, pm.log16 = atof(*++argv), catmore = 1;
+      else
+      {
+         fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
+         exit(1);
+      }
+      if (catmore) /* consumed an extra *argv */
+      {
+         cp = safecat(command, sizeof command, cp, " ");
+         cp = safecat(command, sizeof command, cp, *argv);
+      }
+   }
+   /* If pngvalid is run with no arguments default to a reasonable set of the
+    * tests.
+    */
+   if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
+      pm.ngamma_tests == 0)
+   {
+      /* Make this do all the tests done in the test shell scripts with the same
+       * parameters, where possible.  The limitation is that all the progressive
+       * read and interlace stuff has to be done in separate runs, so only the
+       * basic 'standard' and 'size' tests are done.
+       */
+      pm.test_standard = 1;
+      pm.test_size = 1;
+      pm.test_transform = 1;
+      pm.ngamma_tests = 2U;
+   }
+   if (pm.ngamma_tests > 0 &&
+      pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
+      pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
+      pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
+   {
+      pm.test_gamma_threshold = 1;
+      pm.test_gamma_transform = 1;
+      pm.test_gamma_sbit = 1;
+      pm.test_gamma_scale16 = 1;
+      pm.test_gamma_background = 1;
+      pm.test_gamma_alpha_mode = 1;
+   }
+   else if (pm.ngamma_tests == 0)
+   {
+      /* Nothing to test so turn everything off: */
+      pm.test_gamma_threshold = 0;
+      pm.test_gamma_transform = 0;
+      pm.test_gamma_sbit = 0;
+      pm.test_gamma_scale16 = 0;
+      pm.test_gamma_background = 0;
+      pm.test_gamma_alpha_mode = 0;
+   }
+   Try
+   {
+      /* Make useful base images */
+      make_transform_images(&pm.this);
+      /* Perform the standard and gamma tests. */
+      if (pm.test_standard)
+      {
+         perform_interlace_macro_validation();
+         perform_formatting_test(&pm.this);
+         perform_standard_test(&pm);
+         perform_error_test(&pm);
+      }
+      /* Various oddly sized images: */
+      if (pm.test_size)
+      {
+         make_size_images(&pm.this);
+         perform_size_test(&pm);
+      }
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+      /* Combinatorial transforms: */
+      if (pm.test_transform)
+         perform_transform_test(&pm);
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+#ifdef PNG_READ_GAMMA_SUPPORTED
+      if (pm.ngamma_tests > 0)
+         perform_gamma_test(&pm, summary);
+#endif
+   }
+   Catch_anonymous
+   {
+      fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
+      if (!pm.this.verbose)
+      {
+         if (pm.this.error[0] != 0)
+            fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
+         fprintf(stderr, "pngvalid: run with -v to see what happened\n");
+      }
+      exit(1);
+   }
+   if (summary)
+   {
+      printf("%s: %s (%s point arithmetic)\n",
+         (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+            pm.this.nwarnings)) ? "FAIL" : "PASS",
+         command,
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
+         "floating"
+#else
+         "fixed"
+#endif
+         );
+   }
+   if (memstats)
+   {
+      printf("Allocated memory statistics (in bytes):\n"
+         "\tread  %lu maximum single, %lu peak, %lu total\n"
+         "\twrite %lu maximum single, %lu peak, %lu total\n",
+         (unsigned long)pm.this.read_memory_pool.max_max,
+         (unsigned long)pm.this.read_memory_pool.max_limit,
+         (unsigned long)pm.this.read_memory_pool.max_total,
+         (unsigned long)pm.this.write_memory_pool.max_max,
+         (unsigned long)pm.this.write_memory_pool.max_limit,
+         (unsigned long)pm.this.write_memory_pool.max_total);
+   }
+   /* Do this here to provoke memory corruption errors in memory not directly
+    * allocated by libpng - not a complete test, but better than nothing.
+    */
+   store_delete(&pm.this);
+   /* Error exit if there are any errors, and maybe if there are any
+    * warnings.
+    */
+   if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+       pm.this.nwarnings))
+   {
+      if (!pm.this.verbose)
+         fprintf(stderr, "pngvalid: %s\n", pm.this.error);
+      fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
+          pm.this.nwarnings);
+      exit(1);
+   }
+   /* Success case. */
+   if (touch != NULL)
+   {
+      FILE *fsuccess = fopen(touch, "wt");
+      if (fsuccess != NULL)
+      {
+         int error = 0;
+         fprintf(fsuccess, "PNG validation succeeded\n");
+         fflush(fsuccess);
+         error = ferror(fsuccess);
+         if (fclose(fsuccess) || error)
+         {
+            fprintf(stderr, "%s: write failed\n", touch);
+            exit(1);
+         }
+      }
+   }
+   return 0;
+}
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/README b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/README
new file mode 100644
index 0000000..86583cc
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/README
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG, pngusr.h and pngusr.dfa
+The makefile builds a minimal read-only decoder with embedded libpng
+and zlib.
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the png2pnm application there.
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/makefile b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/makefile
new file mode 100644
index 0000000..9692e0a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/makefile
@@ -0,0 +1,150 @@
+# Makefile for PngMinus (pngm2pnm)
+# Linux / Unix
+#CC=cc
+CC=gcc
+LD=$(CC)
+# If awk fails try
+# make AWK=nawk
+# If cpp fails try
+# make CPP=/lib/cpp
+RM=rm -f
+COPY=cp
+CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. -O1
+C=.c
+O=.o
+L=.a
+E=
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+         inffast$(C) inflate$(C) inftrees$(C) \
+         zutil$(C)
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+         inflate.h inftrees.h zutil.h
+# Machine generated headers
+ZCONF  = zconf.h
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+ZOBJS  = adler32$(O) crc32$(O) \
+         inffast$(O) inflate$(O) inftrees$(O) \
+         zutil$(O)
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+        pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+        pngset$(C) pngtrans$(C)
+        
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+# Machine generated headers
+PNGCONF=pnglibconf.h
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+        pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+        pngset$(O) pngtrans$(O)
+PROGSRCS= pngm2pnm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pngm2pnm$(O)
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+# implicit make rules -------------------------------------------------------
+# note: dependencies do not work on implicit rule lines
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies
+all: pngm2pnm$(E)
+pngm2pnm$(E): $(OBJS)
+        $(LD) -o pngm2pnm$(E) $(OBJS)
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+        $(PNGSRC)/scripts/pnglibconf.dfa \
+        $(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+        $(RM) pnglibconf.h pnglibconf.dfn
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+            DFA_XTRA="pngusr.dfa" $@
+clean:
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) clean
+        $(RM) pngm2pnm$(O)
+        $(RM) pngm2pnm$(E)
+        $(RM) $(OBJS)
+# distclean also removes the copied source and headers
+distclean: clean
+        $(RM) -r scripts # historical reasons
+        $(RM) $(PNGSRCS) $(PNGH)
+        $(RM) $(ZSRCS) $(ZH) $(ZCONF)
+        $(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+        $(RM) $@
+        $(COPY) $(PNGSRC)/$@ $@
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+        $(RM) $@
+        $(COPY) $(ZLIBSRC)/$@ $@
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+        $(RM) $@
+        @for f in zconf.h.in zconf.in.h zconf.h; do\
+            test -r $(ZLIBSRC)/$$f &&\
+            echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+            $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+        done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+pngm2pnm.c: $(PROGSRC)/png2pnm.c
+        $(RM) $@
+        $(COPY) $(PROGSRC)/png2pnm.c $@
+# End of makefile for pngm2pnm
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.dfa b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.dfa
new file mode 100644
index 0000000..8a66d64
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.dfa
@@ -0,0 +1,39 @@
+# pngminim/decoder/pngusr.dfa
+#
+# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+# First all the build options off:
+everything = off
+# All that is required is some read code. This example switches
+# on the sequential read code (see ../preader for a progressive
+# read example).
+option SEQUENTIAL_READ on
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+option FIXED_POINT on
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+option FLOATING_ARITHMETIC off
+# Your program will probably need other options.  The example
+# program here, pngm2pnm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+option SETJMP on
+option STDIO on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.h
new file mode 100644
index 0000000..2991c17
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/decoder/pngusr.h
@@ -0,0 +1,24 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+#ifndef MINRDPNGCONF_H
+#define MINRDPNGCONF_H
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+#define PNG_NO_WARNINGS
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+#endif /* MINRDPNGCONF_H */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/README b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/README
new file mode 100644
index 0000000..f8a8b6d
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/README
@@ -0,0 +1,10 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+The makefile builds a minimal write-only decoder with embedded libpng
+and zlib.
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+If you prefer to use the shared libraries, go to contrib/pngminus
+and build the pnm2png application there.
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/makefile b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/makefile
new file mode 100644
index 0000000..7374a6c
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/makefile
@@ -0,0 +1,149 @@
+# Makefile for PngMinus (pnm2pngm)
+# Linux / Unix
+#CC=cc
+CC=gcc
+LD=$(CC)
+# If awk fails try
+# make AWK=nawk
+# If cpp fails try
+# make CPP=/lib/cpp
+RM=rm -f
+COPY=cp
+CFLAGS=-DPNG_USER_CONFIG -DNO_GZIP -I. -O1
+C=.c
+O=.o
+L=.a
+E=
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+# Zlib
+ZSRCS  = adler32$(C) compress$(C) crc32$(C) deflate$(C) \
+         trees$(C) zutil$(C)
+# Standard headers
+#ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+# Machine generated headers
+ZCONF  = zconf.h
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+# compress is not required; it is needed to link the zlib
+# code because deflate defines an unused API function deflateBound
+# which itself calls compressBound from compress.
+ZOBJS  = adler32$(O) compress$(O) crc32$(O) deflate$(O) \
+         trees$(O) zutil$(O)
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+        pngset$(C) pngtrans$(C) pngwio$(C) pngwrite$(C) \
+        pngwtran$(C) pngwutil$(C)
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+# Machine generated headers
+PNGCONF=pnglibconf.h
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+        pngset$(O) pngtrans$(O) pngwio$(O) pngwrite$(O) \
+        pngwtran$(O) pngwutil$(O)
+PROGSRCS= pnm2pngm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pnm2pngm$(O)
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies
+all: pnm2pngm$(E)
+pnm2pngm$(E): $(OBJS)
+        $(LD) -o pnm2pngm$(E) $(OBJS)
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+        $(PNGSRC)/scripts/pnglibconf.dfa \
+        $(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+        $(RM) pnglibconf.h pnglibconf.dfn
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+            DFA_XTRA="pngusr.dfa" $@
+clean:
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) clean
+        $(RM) pnm2pngm$(O)
+        $(RM) pnm2pngm$(E)
+        $(RM) $(OBJS)
+# distclean also removes the copied source and headers
+distclean: clean
+        $(RM) -r scripts # historical reasons
+        $(RM) $(PNGSRCS) $(PNGH)
+        $(RM) $(ZSRCS) $(ZH) $(ZCONF)
+        $(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+        $(RM) $@
+        $(COPY) $(PNGSRC)/$@ $@
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+        $(RM) $@
+        $(COPY) $(ZLIBSRC)/$@ $@
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+        $(RM) $@
+        @for f in zconf.h.in zconf.in.h zconf.h; do\
+            test -r $(ZLIBSRC)/$$f &&\
+            echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+            $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+        done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+pnm2pngm.c: $(PROGSRC)/pnm2png.c
+        $(RM) $@
+        $(COPY) $(PROGSRC)/pnm2png.c $@
+# End of makefile for pnm2pngm
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.dfa b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.dfa
new file mode 100644
index 0000000..448f821
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.dfa
@@ -0,0 +1,35 @@
+# pngminim/encoder/pngusr.dfa
+#
+# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+# First all the build options off:
+everything = off
+# Switch on the write code - this makes a minimalist encoder
+option WRITE on
+# You must choose fixed or floating point arithmetic:
+# option FLOATING_POINT on
+option FIXED_POINT on
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+# option FLOATING_ARITHMETIC on
+option FLOATING_ARITHMETIC off
+# Your program will probably need other options.  The example
+# program here, pnm2pngm, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+option SETJMP on
+option STDIO on
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.h
new file mode 100644
index 0000000..bafbf13
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/encoder/pngusr.h
@@ -0,0 +1,24 @@
+/* minwrpngconf.h: headers to make a minimal png-write-only library
+ *
+ * Copyright (c) 2007, 2010-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+#ifndef MINWRPNGCONF_H
+#define MINWRPNGCONF_H
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+#define PNG_NO_WARNINGS
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+#endif /* MINWRPNGCONF_H */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/README b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/README
new file mode 100644
index 0000000..e40024e
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/README
@@ -0,0 +1,15 @@
+This demonstrates the use of PNG_USER_CONFIG and pngusr.h
+The makefile builds a minimal read-only progressive decoder with
+embedded libpng, zlib and your system's X library.
+Specify the location of the zlib source (1.2.1 or later) as ZLIBSRC
+on the make command line.
+Edit makefile if required, to find your X library and include files,
+then
+    make ZLIBSRC=directory
+If you prefer to use the shared libraries, go to contrib/gregbook
+and build the rpng2-x application there.
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/makefile b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/makefile
new file mode 100644
index 0000000..a367661
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/makefile
@@ -0,0 +1,165 @@
+# Makefile for PngMinus (rpng2)
+# Linux / Unix
+#CC=cc
+CC=gcc
+LD=$(CC)
+# If awk fails try
+# make AWK=nawk
+# If cpp fails try
+# make CPP=/lib/cpp
+RM=rm -f
+COPY=cp
+#XINC = -I/usr/include                  # old-style, stock X distributions
+#XLIB = -L/usr/lib/X11 -lX11            #  (including SGI IRIX)
+#XINC = -I/usr/openwin/include          # Sun workstations (OpenWindows)
+#XLIB = -L/usr/openwin/lib -lX11
+XINC = -I/usr/X11R6/include             # new X distributions (X.org, etc.)
+XLIB = -L/usr/X11R6/lib -lX11
+#XLIB = -L/usr/X11R6/lib64 -lX11        # e.g., Red Hat on AMD64
+#XINC = -I/usr/local/include            # FreeBSD
+#XLIB = -L/usr/local/lib -lX11
+#LIBS = $(XLIB)
+LIBS = $(XLIB) -lm                      #platforms that need libm
+CFLAGS=-DPNG_USER_CONFIG -DNO_GZCOMPRESS -DNO_GZIP -I. $(XINC) -O1
+C=.c
+O=.o
+L=.a
+E=
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/gregbook
+# Zlib (minimal inflate requirements - crc32 is used by libpng)
+# zutil can be eliminated if you provide your own zcalloc and zcfree
+ZSRCS  = adler32$(C) crc32$(C) \
+         inffast$(C) inflate$(C) inftrees$(C) \
+         zutil$(C)
+# Standard headers
+ZH     = zlib.h crc32.h inffast.h inffixed.h \
+         inflate.h inftrees.h zutil.h
+# Machine generated headers
+ZCONF  = zconf.h
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+ZOBJS  = adler32$(O) crc32$(O) \
+         inffast$(O) inflate$(O) inftrees$(O) \
+         zutil$(O)
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+        pngpread$(C) pngread$(C) pngrio$(C) pngrtran$(C) pngrutil$(C) \
+        pngset$(C) pngtrans$(C)
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+# Machine generated headers
+PNGCONF=pnglibconf.h
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+        pngpread$(O) pngread$(O) pngrio$(O) pngrtran$(O) pngrutil$(O) \
+        pngset$(O) pngtrans$(O)
+PROGSRCS= rpng2-x$(C) readpng2$(C)
+PROGHDRS= readpng2.h
+PROGDOCS= COPYING LICENSE
+PROGOBJS= rpng2-x$(O) readpng2$(O)
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+# implicit make rules -------------------------------------------------------
+.c$(O):
+        $(CC) -c $(CFLAGS) $<
+# dependencies
+all: $(PROGDOCS) rpng2-x$(E)
+rpng2-x$(E): $(OBJS)
+        $(LD) -o rpng2-x$(E) $(OBJS) $(LIBS)
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak\
+        $(PNGSRC)/scripts/pnglibconf.dfa \
+        $(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+        $(RM) pnglibconf.h pnglibconf.dfn
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG"\
+            DFA_XTRA="pngusr.dfa" $@
+clean:
+        $(MAKE) $(MAKEFLAGS) -f $(PNGSRC)/scripts/pnglibconf.mak\
+            srcdir=$(PNGSRC) clean
+        $(RM) rpng2-x$(O)
+        $(RM) rpng2-x$(E)
+        $(RM) $(OBJS)
+# distclean also removes the copied source and headers
+distclean: clean
+        $(RM) -r scripts # historical reasons
+        $(RM) $(PNGSRCS) $(PNGH)
+        $(RM) $(ZSRCS) $(ZH) $(ZCONF)
+        $(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+        $(RM) $@
+        $(COPY) $(PNGSRC)/$@ $@
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+        $(RM) $@
+        $(COPY) $(ZLIBSRC)/$@ $@
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+        $(RM) $@
+        @for f in zconf.h.in zconf.in.h zconf.h; do\
+            test -r $(ZLIBSRC)/$$f &&\
+            echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+            $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+        done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+$(PROGSRCS) $(PROGHDRS) $(PROGDOCS): $(PROGSRC)/$@
+        $(RM) $@
+        $(COPY) $(PROGSRC)/$@ $@
+# End of makefile for rpng2-x
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.dfa b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.dfa
new file mode 100644
index 0000000..0c991d3
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.dfa
@@ -0,0 +1,40 @@
+# pngminim/preader/pngusr.dfa
+#
+# Copyright (c) 2010-2011 Glenn Randers-Pehrson
+#
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+# First all the build options off:
+everything = off
+# Just switch on the progressive read code
+option PROGRESSIVE_READ on
+# You may choose fixed or floating point APIs:
+# option FLOATING_POINT on
+option FIXED_POINT on
+# You must chose the internal fixed point implementation or to
+# use the system floating point.  The latter is considerably
+# smaller (by about 1kbyte on an x86 system):
+option FLOATING_ARITHMETIC on
+# option FLOATING_ARITHMETIC off
+# Your program will probably need other options.  The example
+# program here, rpng2-x, requires the following.  Take a look
+# at pnglibconf.h to find out the full set of what has to be
+# enabled to make the following work.
+option SETJMP on
+option STDIO on
+option READ_bKGD on
+option READ_GAMMA on
+option READ_EXPAND on
+option READ_STRIP_16_TO_8 on
+option READ_GRAY_TO_RGB on
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.h
new file mode 100644
index 0000000..7db806f
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminim/preader/pngusr.h
@@ -0,0 +1,24 @@
+/* minrdpngconf.h: headers to make a minimal png-read-only library
+ *
+ * Copyright (c) 2009, 2010-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * Derived from pngcrush.h, Copyright 1998-2007, Glenn Randers-Pehrson
+ */
+#ifndef MINPRDPNGCONF_H
+#define MINPRDPNGCONF_H
+/* To include pngusr.h set -DPNG_USER_CONFIG in CPPFLAGS */
+/* List options to turn off features of the build that do not
+ * affect the API (so are not recorded in pnglibconf.h)
+ */
+#define PNG_NO_WARNINGS
+#define PNG_ALIGN_TYPE PNG_ALIGN_NONE
+#endif /* MINPRDPNGCONF_H */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/README b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/README
new file mode 100644
index 0000000..b0516ec
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/README
@@ -0,0 +1,153 @@
+PngMinus
+--------
+(copyright Willem van Schaik, 1999)
+License
+-------
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby granted,
+provided that the above copyright notice appear in all copies and
+that both that copyright notice and this permission notice appear in
+supporting documentation. This software is provided "as is" without
+express or implied warranty.
+Some history
+------------
+Soon after the creation of PNG in 1995, the need was felt for a set of
+pnmtopng / pngtopnm utilities. Independantly Alexander Lehmann and I
+(Willem van Schaik) started such a project. Luckily we discovered this
+and merged the two together into pnmtopng.tar.gz, which is available
+from a/o ftp://ftp.simplesystems.org/pub/libpng/png/.
+These two utilities have many, many options and make use of most of the
+features of PNG, like gamma, alpha, sbit, text-chunks, etc. This makes
+the utilities quite complex and by now not anymore very maintainable.
+When we wrote these programs, libpng was still in an early stage.
+Therefore, lots of the functionality that we put in our software can now
+be done using transform-functions in libpng.
+Finally, to compile these programs, you need to have installed and
+compiled three libraries: libpng, zlib and netpbm. Especially the latter
+makes the whole setup a bit bulky. But that's unavoidable given the many
+features of pnmtopng.
+What now
+--------
+At this moment libpng is in a very stable state and can do much of the
+work done in pnmtopng. Also, pnmtopng needs to be upgraded to the new
+interface of libpng. Hence, it is time for a rewrite from the ground up
+of pnmtopng and pngtopnm. This will happen in the near future (stay
+tuned). The new package will get a different name to distinguish it from
+the old one: PngPlus.
+To experiment a bit with the new interface of libpng, I started off with
+a small prototype that contains only the basic functionality. It doesn't
+have any of the options to read or write special chunks and it will do
+no gamma correction. But this makes it also a simple program that is
+quite easy to understand and can serve well as a template for other
+software developments. (By now there are of course a couple of programs,
+like Greg Roelofs' rpng/wpng, that can be used just as good.)
+Can and can not
+---------------
+As this is the small brother of the future PngPlus, I called this fellow
+PngMinus. Because I started this development in good-old Turbo-C, I
+avoided the use the netpbm library, which requires DOS extenders. Again,
+another reason to call it PngMinus (minus netpbm :-). So, part of the
+program are some elementary routines to read / write pgm- and ppm-files.
+It does not read b&w pbm-files.
+The downside of this approach is that you can not use them on images
+that require blocks of memory bigger than 64k (the DOS version). For
+larger images you will get an out-of-memory error.
+As said before, PngMinus doesn't correct for gamma. When reading
+png-files you can do this just as well by piping the output of png2pnm
+to pnmgamma, one of the standard PbmPlus tools. This same scenario will
+most probably also be followed in the full-blown future PngPlus, with
+the addition of course of the possibility to create gamma-chunks when
+writing png-files.
+On the other hand it supports alpha-channels. When reading a png-image
+you can write the alpha-channel into a pgm-file. And when creating an
+RGB+A png-image, you just combine a ppm-file with a corresponding
+pgm-file containing the alpha-channel. When reading, transparency chunks
+are converted into an alpha-channel and from there on treated the same
+way.
+Finally you can opt for writing ascii or binary pgm- and ppm-files. When
+the bit-depth is 16, the format will always be ascii.
+Using it
+--------
+To distinguish them from pnmtopng and PngPlus, the utilities are named
+png2pnm and pnm2png (2 instead of to). The input- and output-files can
+be given as parameters or through redirection. Therefore the programs
+can be part of a pipe.
+To list the options type "png2pnm -h" or "pnm2png -h".
+Just like Scandinavian furniture
+--------------------------------
+You have to put it together yourself. I did test the software under
+MS-DOS with Turbo-C 3.0 and under RedHat Linux 4.2 with gcc. In both
+cases I used libpng-1.0.4 and zlib-1.1.3. Later versions should be OK,
+however some older libpng versions have a bug in pngmem.c when using
+Turbo-C 3.0 (see below).
+You can build it using one of the two makefiles (make -f makefile.###)
+or use the batch/script files pngminus.bat / pngminus.sh. This assumes
+that you have built the libraries in ../libpng and ../zlib. Using Linux,
+make sure that you have built libpng with makefile.std and not
+makefile.linux (also called .lnx in earlier versions of libpng). The
+latter creates a .so shared-library, while the PngMinus makefile assumes
+a normal .a static library.
+If you create a ../pngsuite directory and then store the basn####.png
+files from PngSuite (http://www.schaik.com/pngsuite/) in there, you can
+test in one go the proper functioning of PngMinus, see png2pnm.bat and
+pnm2png.bat (or the .sh versions).
+Warranty
+-------
+Please, remember that this was just a small experiment to learn a few
+things. It will have many unforeseen features <vbg>. Who said bugs? Use
+it when you are in need for something simple or when you want to start
+developing your own stuff.
+The Turbo bug
+-------------
+** pngmem.old
+          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+          hptr += 16L;
+** pngmem.c
+          hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+          hptr = hptr + 16L;
+**
+** pngmem.old
+          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
+          hptr += (png_uint_32)65536L;
+** pngmem.c
+          png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
+          hptr = hptr + 65536L;
+**
+The end
+-------
+Willem van Schaik
+mailto:willem@schaik.com
+http://www.schaik.com/png/
+-------
+Oct 1999
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.std b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.std
new file mode 100644
index 0000000..a121032
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.std
@@ -0,0 +1,65 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# Linux / Unix
+#CC=cc
+CC=gcc
+LD=$(CC)
+RM=rm -f
+#PNGPATH = /usr/local
+#PNGINC = -I$(PNGPATH)/include/libpng15
+#PNGLIB = -L$(PNGPATH)/lib -lpng15
+#PNGLIBS = $(PNGPATH)/lib/libpng15.a
+PNGINC = -I../..
+PNGLIB = -L../.. -lpng
+PNGLIBS = ../../libpng.a
+#ZPATH = /usr/local
+#ZINC = -I$(ZPATH)/include
+#ZLIB = -L$(ZPATH)/lib -lz
+#ZLIBS = $(ZPATH)/lib/libz.a
+ZINC = -I../../../zlib
+ZLIB = -L../../../zlib -lz
+ZLIBS = ../../../zlib/libz.a
+CFLAGS=$(PNGINC) $(ZINC)
+LDLIBS=$(PNGLIB) $(ZLIB)
+LDLIBSS=$(PNGLIBS) $(ZLIBS)
+C=.c
+O=.o
+L=.a
+E=
+# dependencies
+#all: png2pnm$(E) pnm2png$(E)
+all: png2pnm$(E) pnm2png$(E) png2pnm-static$(E) pnm2png-static$(E)
+png2pnm$(O): png2pnm$(C)
+        $(CC) -c $(CFLAGS) png2pnm$(C)
+png2pnm$(E): png2pnm$(O)
+        $(LD) $(LDFLAGS) -o png2pnm$(E) png2pnm$(O) $(LDLIBS) -lm
+png2pnm-static$(E): png2pnm$(O)
+        $(LD) $(LDFLAGS) -o png2pnm-static$(E) png2pnm$(O) $(LDLIBSS) -lm
+pnm2png$(O): pnm2png$(C)
+        $(CC) -c $(CFLAGS) pnm2png$(C)
+pnm2png$(E): pnm2png$(O)
+        $(LD) $(LDFLAGS) -o pnm2png$(E) pnm2png$(O) $(LDLIBS) -lm
+pnm2png-static$(E): pnm2png$(O)
+        $(LD) $(LDFLAGS) -o pnm2png-static$(E) pnm2png$(O) $(LDLIBSS) -lm
+clean:
+        $(RM) png2pnm$(O)
+        $(RM) pnm2png$(O)
+        $(RM) png2pnm$(E)
+        $(RM) pnm2png$(E)
+        $(RM) png2pnm-static$(E)
+        $(RM) pnm2png-static$(E)
+# End of makefile for png2pnm / pnm2png
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.tc3 b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.tc3
new file mode 100644
index 0000000..01062cc
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makefile.tc3
@@ -0,0 +1,38 @@
+# Makefile for PngMinus (png2pnm and pnm2png)
+# TurboC++ 3.0
+CC=tcc -Ic:\tc3\inc
+LD=tcc -Lc:\tc3\lib
+LB=tlib
+RM=del
+CP=copy
+MODEL=l
+CCFLAGS=-O -m$(MODEL) -I..\libpng -I..\zlib
+LDFLAGS=-m$(MODEL) -L..\libpng -L..\zlib
+C=.c
+O=.obj
+L=.lib
+E=.exe
+# dependencies
+all: png2pnm$(E) pnm2png$(E)
+png2pnm$(O): png2pnm$(C)
+        $(CC) -c $(CCFLAGS) png2pnm$(C)
+png2pnm$(E): png2pnm$(O)
+        $(LD) $(LDFLAGS) png2pnm$(O) libpng$(L) zlib$(L)
+pnm2png$(O): pnm2png$(C)
+        $(CC) -c $(CCFLAGS) pnm2png$(C)
+pnm2png$(E): pnm2png$(O)
+        $(LD) $(LDFLAGS) pnm2png$(O) libpng$(L) zlib$(L)
+clean:
+        $(RM) *$(O)
+        $(RM) *$(E)
+# End of makefile for png2pnm / pnm2png
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makevms.com b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makevms.com
new file mode 100644
index 0000000..96c3147
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/makevms.com
@@ -0,0 +1,92 @@
+$!------------------------------------------------------------------------------
+$! make Contrib programs of libpng under OpenVMS
+$!
+$!
+$! Look for the compiler used
+$!
+$ zlibsrc = "[---.zlib]"
+$ ccopt="/include=(''zlibsrc',[--])"
+$ if f$getsyi("HW_MODEL").ge.1024
+$ then
+$  ccopt = "/prefix=all"+ccopt
+$  comp  = "__decc__=1"
+$  if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$ else
+$  if f$search("SYS$SYSTEM:DECC$COMPILER.EXE").eqs.""
+$   then
+$    if f$trnlnm("SYS").eqs."" then define sys sys$library:
+$    if f$search("SYS$SYSTEM:VAXC.EXE").eqs.""
+$     then
+$      comp  = "__gcc__=1"
+$      CC :== GCC
+$     else
+$      comp = "__vaxc__=1"
+$     endif
+$   else
+$    if f$trnlnm("SYS").eqs."" then define sys decc$library_include:
+$    ccopt = "/decc/prefix=all"+ccopt
+$    comp  = "__decc__=1"
+$  endif
+$ endif
+$ open/write lopt lib.opt
+$ write lopt "[--]libpng.olb/lib"
+$ write lopt "''zlibsrc'libz.olb/lib"
+$ close lopt
+$ open/write xopt x11.opt
+$ write xopt "sys$library:decw$xlibshr.exe/share"
+$ close xopt
+$ write sys$output "Compiling PNG contrib programs ..."
+$   write sys$output "Building pnm2png..."
+$   CALL MAKE pnm2png.OBJ "cc ''CCOPT' pnm2png" -
+        pnm2png.c
+$   call make pnm2png.exe -
+        "LINK pnm2png,lib.opt/opt" -
+        pnm2png.obj
+$   write sys$output "Building png2pnm..."
+$   CALL MAKE png2pnm.OBJ "cc ''CCOPT' png2pnm" -
+        png2pnm.c
+$   call make png2pnm.exe -
+        "LINK png2pnm,lib.opt/opt" -
+        png2pnm.obj
+$ exit
+$!
+$!
+$MAKE: SUBROUTINE   !SUBROUTINE TO CHECK DEPENDENCIES
+$ V = 'F$Verify(0)
+$! P1 = What we are trying to make
+$! P2 = Command to make it
+$! P3 - P8  What it depends on
+$
+$ If F$Search(P1) .Eqs. "" Then Goto Makeit
+$ Time = F$CvTime(F$File(P1,"RDT"))
+$arg=3
+$Loop:
+$       Argument = P'arg
+$       If Argument .Eqs. "" Then Goto Exit
+$       El=0
+$Loop2:
+$       File = F$Element(El," ",Argument)
+$       If File .Eqs. " " Then Goto Endl
+$       AFile = ""
+$Loop3:
+$       OFile = AFile
+$       AFile = F$Search(File)
+$       If AFile .Eqs. "" .Or. AFile .Eqs. OFile Then Goto NextEl
+$       If F$CvTime(F$File(AFile,"RDT")) .Ges. Time Then Goto Makeit
+$       Goto Loop3
+$NextEL:
+$       El = El + 1
+$       Goto Loop2
+$EndL:
+$ arg=arg+1
+$ If arg .Le. 8 Then Goto Loop
+$ Goto Exit
+$
+$Makeit:
+$ VV=F$VERIFY(0)
+$ write sys$output P2
+$ 'P2
+$ VV='F$Verify(VV)
+$Exit:
+$ If V Then Set Verify
+$ENDSUBROUTINE
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.bat b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.bat
new file mode 100644
index 0000000..85abe3c
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.bat
@@ -0,0 +1,41 @@
+REM -- grayscale
+png2pnm.exe -noraw ..\pngsuite\basn0g01.png basn0g01.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g02.png basn0g02.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g04.png basn0g04.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g08.png basn0g08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn0g16.png basn0g16.pgm
+REM -- full-color
+png2pnm.exe -noraw ..\pngsuite\basn2c08.png basn2c08.ppm
+png2pnm.exe -noraw ..\pngsuite\basn2c16.png basn2c16.ppm
+REM -- palletted
+png2pnm.exe -noraw ..\pngsuite\basn3p01.png basn3p01.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p02.png basn3p02.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p04.png basn3p04.ppm
+png2pnm.exe -noraw ..\pngsuite\basn3p08.png basn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -noraw ..\pngsuite\basn4a08.png basn4a08.pgm
+png2pnm.exe -noraw ..\pngsuite\basn4a16.png basn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha basn6a08.pgm ..\pngsuite\basn6a08.png basn6a08.ppm
+png2pnm.exe -noraw -alpha basn6a16.pgm ..\pngsuite\basn6a16.png basn6a16.ppm
+REM -- grayscale
+png2pnm.exe -raw ..\pngsuite\basn0g01.png rawn0g01.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g02.png rawn0g02.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g04.png rawn0g04.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g08.png rawn0g08.pgm
+png2pnm.exe -raw ..\pngsuite\basn0g16.png rawn0g16.pgm
+REM -- full-color
+png2pnm.exe -raw ..\pngsuite\basn2c08.png rawn2c08.ppm
+png2pnm.exe -raw ..\pngsuite\basn2c16.png rawn2c16.ppm
+REM -- palletted
+png2pnm.exe -raw ..\pngsuite\basn3p01.png rawn3p01.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p02.png rawn3p02.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p04.png rawn3p04.ppm
+png2pnm.exe -raw ..\pngsuite\basn3p08.png rawn3p08.ppm
+REM -- gray with alpha-channel
+png2pnm.exe -raw ..\pngsuite\basn4a08.png rawn4a08.pgm
+png2pnm.exe -raw ..\pngsuite\basn4a16.png rawn4a16.pgm
+REM -- color with alpha-channel
+png2pnm.exe -noraw -alpha rawn6a08.pgm ..\pngsuite\basn6a08.png rawn6a08.ppm
+png2pnm.exe -noraw -alpha rawn6a16.pgm ..\pngsuite\basn6a16.png rawn6a16.ppm
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.c
new file mode 100644
index 0000000..ef28d90
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.c
@@ -0,0 +1,430 @@
+/*
+ *  png2pnm.c --- conversion from PNG-file to PGM/PPM-file
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
+ *
+ *  version 1.0 - 1999.10.15 - First version.
+ *
+ *  Permission to use, copy, modify, and distribute this software and
+ *  its documentation for any purpose and without fee is hereby granted,
+ *  provided that the above copyright notice appear in all copies and
+ *  that both that copyright notice and this permission notice appear in
+ *  supporting documentation. This software is provided "as is" without
+ *  express or implied warranty.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef __TURBOC__
+#include <mem.h>
+#include <fcntl.h>
+#endif
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+#ifdef __TURBOC__
+#define STDIN  0
+#define STDOUT 1
+#define STDERR 2
+#endif
+/* to make png2pnm verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+#include "png.h"
+/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
+/* function prototypes */
+int  main (int argc, char *argv[]);
+void usage ();
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha);
+/*
+ *  main
+ */
+int main(int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_wr = stdout;
+  FILE *fp_al = NULL;
+  BOOL raw = TRUE;
+  BOOL alpha = FALSE;
+  int argi;
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'n':
+          raw = FALSE;
+          break;
+        case 'r':
+          raw = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "wb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  can not create alpha-channel file %s\n", argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage();
+          exit(0);
+          break;
+        default:
+          fprintf (stderr, "PNG2PNM\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage();
+          exit(1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+             fprintf (stderr, "PNG2PNM\n");
+            fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+            exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNG2PNM\n");
+        fprintf (stderr, "Error:  can not create file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNG2PNM\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage();
+      exit(1);
+    }
+  } /* end for */
+#ifdef __TURBOC__
+  /* set stdin/stdout if required to binary */
+  if (fp_rd == stdin)
+  {
+    setmode (STDIN, O_BINARY);
+  }
+  if ((raw) && (fp_wr == stdout))
+  {
+    setmode (STDOUT, O_BINARY);
+  }
+#endif
+  /* call the conversion program itself */
+  if (png2pnm (fp_rd, fp_wr, fp_al, raw, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  unsuccessful conversion of PNG-image\n");
+    exit(1);
+  }
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+  return 0;
+}
+/*
+ *  usage
+ */
+void usage()
+{
+  fprintf (stderr, "PNG2PNM\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+#ifdef __TURBOC__
+  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
+#else
+  fprintf (stderr, "   for Linux (and Unix) compilers\n");
+#endif
+  fprintf (stderr, "Usage:  png2pnm [options] <file>.png [<file>.pnm]\n");
+  fprintf (stderr, "   or:  ... | png2pnm [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -r[aw]   write pnm-file in binary format (P4/P5/P6) (default)\n");
+  fprintf (stderr, "   -n[oraw] write pnm-file in ascii format (P1/P2/P3)\n");
+  fprintf (stderr, "   -a[lpha] <file>.pgm write PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+/*
+ *  png2pnm
+ */
+BOOL png2pnm (FILE *png_file, FILE *pnm_file, FILE *alpha_file, BOOL raw, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info        *info_ptr = NULL;
+  png_byte      buf[8];
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  png_uint_32   row_bytes;
+  png_uint_32   width;
+  png_uint_32   height;
+  int           bit_depth;
+  int           channels;
+  int           color_type;
+  int           alpha_present;
+  int           row, col;
+  int           ret;
+  int           i;
+  long          dep_16;
+  /* read and check signature in PNG file */
+  ret = fread (buf, 1, 8, png_file);
+  if (ret != 8)
+    return FALSE;
+  ret = png_sig_cmp (buf, 0, 8);
+  if (ret)
+    return FALSE;
+  /* create png and info structures */
+  png_ptr = png_create_read_struct (PNG_LIBPNG_VER_STRING,
+    NULL, NULL, NULL);
+  if (!png_ptr)
+    return FALSE;   /* out of memory */
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_read_struct (&png_ptr, NULL, NULL);
+    return FALSE;   /* out of memory */
+  }
+  if (setjmp (png_jmpbuf(png_ptr)))
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+  /* set up the input control for C streams */
+  png_init_io (png_ptr, png_file);
+  png_set_sig_bytes (png_ptr, 8);  /* we already read the 8 signature bytes */
+  /* read the file information */
+  png_read_info (png_ptr, info_ptr);
+  /* get size and bit-depth of the PNG-image */
+  png_get_IHDR (png_ptr, info_ptr,
+    &width, &height, &bit_depth, &color_type,
+    NULL, NULL, NULL);
+  /* set-up the transformations */
+  /* transform paletted images into full-color rgb */
+  if (color_type == PNG_COLOR_TYPE_PALETTE)
+    png_set_expand (png_ptr);
+  /* expand images to bit-depth 8 (only applicable for grayscale images) */
+  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+    png_set_expand (png_ptr);
+  /* transform transparency maps into full alpha-channel */
+  if (png_get_valid (png_ptr, info_ptr, PNG_INFO_tRNS))
+    png_set_expand (png_ptr);
+#ifdef NJET
+  /* downgrade 16-bit images to 8 bit */
+  if (bit_depth == 16)
+    png_set_strip_16 (png_ptr);
+  /* transform grayscale images into full-color */
+  if (color_type == PNG_COLOR_TYPE_GRAY ||
+    color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    png_set_gray_to_rgb (png_ptr);
+  /* only if file has a file gamma, we do a correction */
+  if (png_get_gAMA (png_ptr, info_ptr, &file_gamma))
+    png_set_gamma (png_ptr, (double) 2.2, file_gamma);
+#endif
+  /* all transformations have been registered; now update info_ptr data,
+   * get rowbytes and channels, and allocate image memory */
+  png_read_update_info (png_ptr, info_ptr);
+  /* get the new color-type and bit-depth (after expansion/stripping) */
+  png_get_IHDR (png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
+    NULL, NULL, NULL);
+  /* check for 16-bit files */
+  if (bit_depth == 16)
+  {
+    raw = FALSE;
+#ifdef __TURBOC__
+    pnm_file->flags &= ~((unsigned) _F_BIN);
+#endif
+  }
+  /* calculate new number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should never happen */
+  alpha_present = (channels - 1) % 2;
+  /* check if alpha is expected to be present in file */
+  if (alpha && !alpha_present)
+  {
+    fprintf (stderr, "PNG2PNM\n");
+    fprintf (stderr, "Error:  PNG-file doesn't contain alpha channel\n");
+    exit (1);
+  }
+  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+  row_bytes = png_get_rowbytes (png_ptr, info_ptr);
+  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL) {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    return FALSE;
+  }
+  if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+  {
+    png_destroy_read_struct (&png_ptr, &info_ptr, NULL);
+    free (png_pixels);
+    png_pixels = NULL;
+    return FALSE;
+  }
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < (height); i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+  /* now we can go ahead and just read the whole image */
+  png_read_image (png_ptr, row_pointers);
+  /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+  png_read_end (png_ptr, info_ptr);
+  /* clean up after the read, and free any memory allocated - REQUIRED */
+  png_destroy_read_struct (&png_ptr, &info_ptr, (png_infopp) NULL);
+  /* write header of PNM file */
+  if ((color_type == PNG_COLOR_TYPE_GRAY) ||
+      (color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  else if ((color_type == PNG_COLOR_TYPE_RGB) ||
+           (color_type == PNG_COLOR_TYPE_RGB_ALPHA))
+  {
+    fprintf (pnm_file, "%s\n", (raw) ? "P6" : "P3");
+    fprintf (pnm_file, "%d %d\n", (int) width, (int) height);
+    fprintf (pnm_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  /* write header of PGM file with alpha channel */
+  if ((alpha) &&
+      ((color_type == PNG_COLOR_TYPE_GRAY_ALPHA) ||
+       (color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+  {
+    fprintf (alpha_file, "%s\n", (raw) ? "P5" : "P2");
+    fprintf (alpha_file, "%d %d\n", (int) width, (int) height);
+    fprintf (alpha_file, "%ld\n", ((1L << (int) bit_depth) - 1L));
+  }
+  /* write data to PNM file */
+  pix_ptr = png_pixels;
+  for (row = 0; row < height; row++)
+  {
+    for (col = 0; col < width; col++)
+    {
+      for (i = 0; i < (channels - alpha_present); i++)
+      {
+        if (raw)
+          fputc ((int) *pix_ptr++ , pnm_file);
+        else
+          if (bit_depth == 16){
+            dep_16 = (long) *pix_ptr++;
+            fprintf (pnm_file, "%ld ", (dep_16 << 8) + ((long) *pix_ptr++));
+          }
+          else
+            fprintf (pnm_file, "%ld ", (long) *pix_ptr++);
+      }
+      if (alpha_present)
+      {
+        if (!alpha)
+        {
+          pix_ptr++; /* alpha */
+          if (bit_depth == 16)
+            pix_ptr++;
+        }
+        else /* output alpha-channel as pgm file */
+        {
+          if (raw)
+            fputc ((int) *pix_ptr++ , alpha_file);
+          else
+            if (bit_depth == 16){
+              dep_16 = (long) *pix_ptr++;
+              fprintf (alpha_file, "%ld ", (dep_16 << 8) + (long) *pix_ptr++);
+            }
+            else
+              fprintf (alpha_file, "%ld ", (long) *pix_ptr++);
+        }
+      } /* if alpha_present */
+      if (!raw)
+        if (col % 4 == 3)
+          fprintf (pnm_file, "\n");
+    } /* end for col */
+    if (!raw)
+      if (col % 4 != 0)
+        fprintf (pnm_file, "\n");
+  } /* end for row */
+  if (row_pointers != (unsigned char**) NULL)
+    free (row_pointers);
+  if (png_pixels != (unsigned char*) NULL)
+    free (png_pixels);
+  return TRUE;
+} /* end of source */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.sh b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.sh
new file mode 100755
index 0000000..ee39664
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/png2pnm.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# -- grayscale
+./png2pnm -noraw ../pngsuite/basn0g01.png basn0g01.pgm
+./png2pnm -noraw ../pngsuite/basn0g02.png basn0g02.pgm
+./png2pnm -noraw ../pngsuite/basn0g04.png basn0g04.pgm
+./png2pnm -noraw ../pngsuite/basn0g08.png basn0g08.pgm
+./png2pnm -noraw ../pngsuite/basn0g16.png basn0g16.pgm
+# -- full-color
+./png2pnm -noraw ../pngsuite/basn2c08.png basn2c08.ppm
+./png2pnm -noraw ../pngsuite/basn2c16.png basn2c16.ppm
+# -- palletted
+./png2pnm -noraw ../pngsuite/basn3p01.png basn3p01.ppm
+./png2pnm -noraw ../pngsuite/basn3p02.png basn3p02.ppm
+./png2pnm -noraw ../pngsuite/basn3p04.png basn3p04.ppm
+./png2pnm -noraw ../pngsuite/basn3p08.png basn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -noraw ../pngsuite/basn4a08.png basn4a08.pgm
+./png2pnm -noraw ../pngsuite/basn4a16.png basn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha basn6a08.pgm ../pngsuite/basn6a08.png basn6a08.ppm
+./png2pnm -noraw -alpha basn6a16.pgm ../pngsuite/basn6a16.png basn6a16.ppm
+# -- grayscale
+./png2pnm -raw ../pngsuite/basn0g01.png rawn0g01.pgm
+./png2pnm -raw ../pngsuite/basn0g02.png rawn0g02.pgm
+./png2pnm -raw ../pngsuite/basn0g04.png rawn0g04.pgm
+./png2pnm -raw ../pngsuite/basn0g08.png rawn0g08.pgm
+./png2pnm -raw ../pngsuite/basn0g16.png rawn0g16.pgm
+# -- full-color
+./png2pnm -raw ../pngsuite/basn2c08.png rawn2c08.ppm
+./png2pnm -raw ../pngsuite/basn2c16.png rawn2c16.ppm
+# -- palletted
+./png2pnm -raw ../pngsuite/basn3p01.png rawn3p01.ppm
+./png2pnm -raw ../pngsuite/basn3p02.png rawn3p02.ppm
+./png2pnm -raw ../pngsuite/basn3p04.png rawn3p04.ppm
+./png2pnm -raw ../pngsuite/basn3p08.png rawn3p08.ppm
+# -- gray with alpha-channel
+./png2pnm -raw ../pngsuite/basn4a08.png rawn4a08.pgm
+./png2pnm -raw ../pngsuite/basn4a16.png rawn4a16.pgm
+# -- color with alpha-channel
+./png2pnm -noraw -alpha rawn6a08.pgm ../pngsuite/basn6a08.png rawn6a08.ppm
+./png2pnm -noraw -alpha rawn6a16.pgm ../pngsuite/basn6a16.png rawn6a16.ppm
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.bat b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.bat
new file mode 100644
index 0000000..5f8d2d4
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.bat
@@ -0,0 +1,4 @@
+make -f makefile.tc3
+call png2pnm.bat
+call pnm2png.bat
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.sh b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.sh
new file mode 100755
index 0000000..adcef55
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pngminus.sh
@@ -0,0 +1,5 @@
+#!/bin/sh
+make -f makefile.std
+sh png2pnm.sh
+sh pnm2png.sh
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.bat b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.bat
new file mode 100644
index 0000000..5b9977a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.bat
@@ -0,0 +1,41 @@
+REM -- grayscale
+pnm2png.exe basn0g01.pgm basn0g01.png
+pnm2png.exe basn0g02.pgm basn0g02.png
+pnm2png.exe basn0g04.pgm basn0g04.png
+pnm2png.exe basn0g08.pgm basn0g08.png
+pnm2png.exe basn0g16.pgm basn0g16.png
+REM -- full-color
+pnm2png.exe basn2c08.ppm basn2c08.png
+pnm2png.exe basn2c16.ppm basn2c16.png
+REM -- palletted
+pnm2png.exe basn3p01.ppm basn3p01.png
+pnm2png.exe basn3p02.ppm basn3p02.png
+pnm2png.exe basn3p04.ppm basn3p04.png
+pnm2png.exe basn3p08.ppm basn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+pnm2png.exe -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+pnm2png.exe -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+REM -- grayscale
+pnm2png.exe rawn0g01.pgm rawn0g01.png
+pnm2png.exe rawn0g02.pgm rawn0g02.png
+pnm2png.exe rawn0g04.pgm rawn0g04.png
+pnm2png.exe rawn0g08.pgm rawn0g08.png
+pnm2png.exe rawn0g16.pgm rawn0g16.png
+REM -- full-color
+pnm2png.exe rawn2c08.ppm rawn2c08.png
+pnm2png.exe rawn2c16.ppm rawn2c16.png
+REM -- palletted
+pnm2png.exe rawn3p01.ppm rawn3p01.png
+pnm2png.exe rawn3p02.ppm rawn3p02.png
+pnm2png.exe rawn3p04.ppm rawn3p04.png
+pnm2png.exe rawn3p08.ppm rawn3p08.png
+REM -- gray with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+REM -- color with alpha-channel
+pnm2png.exe -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+pnm2png.exe -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.c
new file mode 100644
index 0000000..2f321cc
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.c
@@ -0,0 +1,533 @@
+/*
+ *  pnm2png.c --- conversion from PBM/PGM/PPM-file to PNG-file
+ *  copyright (C) 1999 by Willem van Schaik <willem@schaik.com>
+ *
+ *  version 1.0 - 1999.10.15 - First version.
+ *
+ *  Permission to use, copy, modify, and distribute this software and
+ *  its documentation for any purpose and without fee is hereby granted,
+ *  provided that the above copyright notice appear in all copies and
+ *  that both that copyright notice and this permission notice appear in
+ *  supporting documentation. This software is provided "as is" without
+ *  express or implied warranty.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#ifdef __TURBOC__
+#include <mem.h>
+#include <fcntl.h>
+#endif
+#ifndef BOOL
+#define BOOL unsigned char
+#endif
+#ifndef TRUE
+#define TRUE (BOOL) 1
+#endif
+#ifndef FALSE
+#define FALSE (BOOL) 0
+#endif
+#define STDIN  0
+#define STDOUT 1
+#define STDERR 2
+/* to make pnm2png verbose so we can find problems (needs to be before png.h) */
+#ifndef PNG_DEBUG
+#define PNG_DEBUG 0
+#endif
+#include "png.h"
+/* Define png_jmpbuf() in case we are using a pre-1.0.6 version of libpng */
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
+/* function prototypes */
+int  main (int argc, char *argv[]);
+void usage ();
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha);
+void get_token(FILE *pnm_file, char *token);
+png_uint_32 get_data (FILE *pnm_file, int depth);
+png_uint_32 get_value (FILE *pnm_file, int depth);
+/*
+ *  main
+ */
+int main(int argc, char *argv[])
+{
+  FILE *fp_rd = stdin;
+  FILE *fp_al = NULL;
+  FILE *fp_wr = stdout;
+  BOOL interlace = FALSE;
+  BOOL alpha = FALSE;
+  int argi;
+  for (argi = 1; argi < argc; argi++)
+  {
+    if (argv[argi][0] == '-')
+    {
+      switch (argv[argi][1])
+      {
+        case 'i':
+          interlace = TRUE;
+          break;
+        case 'a':
+          alpha = TRUE;
+          argi++;
+          if ((fp_al = fopen (argv[argi], "rb")) == NULL)
+          {
+            fprintf (stderr, "PNM2PNG\n");
+            fprintf (stderr, "Error:  alpha-channel file %s does not exist\n",
+               argv[argi]);
+            exit (1);
+          }
+          break;
+        case 'h':
+        case '?':
+          usage();
+          exit(0);
+          break;
+        default:
+          fprintf (stderr, "PNM2PNG\n");
+          fprintf (stderr, "Error:  unknown option %s\n", argv[argi]);
+          usage();
+          exit(1);
+          break;
+      } /* end switch */
+    }
+    else if (fp_rd == stdin)
+    {
+      if ((fp_rd = fopen (argv[argi], "rb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  file %s does not exist\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else if (fp_wr == stdout)
+    {
+      if ((fp_wr = fopen (argv[argi], "wb")) == NULL)
+      {
+        fprintf (stderr, "PNM2PNG\n");
+        fprintf (stderr, "Error:  can not create PNG-file %s\n", argv[argi]);
+        exit (1);
+      }
+    }
+    else
+    {
+      fprintf (stderr, "PNM2PNG\n");
+      fprintf (stderr, "Error:  too many parameters\n");
+      usage();
+      exit (1);
+    }
+  } /* end for */
+#ifdef __TURBOC__
+  /* set stdin/stdout to binary, we're reading the PNM always! in binary format */
+  if (fp_rd == stdin)
+  {
+    setmode (STDIN, O_BINARY);
+  }
+  if (fp_wr == stdout)
+  {
+    setmode (STDOUT, O_BINARY);
+  }
+#endif
+  /* call the conversion program itself */
+  if (pnm2png (fp_rd, fp_wr, fp_al, interlace, alpha) == FALSE)
+  {
+    fprintf (stderr, "PNM2PNG\n");
+    fprintf (stderr, "Error:  unsuccessful converting to PNG-image\n");
+    exit (1);
+  }
+  /* close input file */
+  fclose (fp_rd);
+  /* close output file */
+  fclose (fp_wr);
+  /* close alpha file */
+  if (alpha)
+    fclose (fp_al);
+  return 0;
+}
+/*
+ *  usage
+ */
+void usage()
+{
+  fprintf (stderr, "PNM2PNG\n");
+  fprintf (stderr, "   by Willem van Schaik, 1999\n");
+#ifdef __TURBOC__
+  fprintf (stderr, "   for Turbo-C and Borland-C compilers\n");
+#else
+  fprintf (stderr, "   for Linux (and Unix) compilers\n");
+#endif
+  fprintf (stderr, "Usage:  pnm2png [options] <file>.<pnm> [<file>.png]\n");
+  fprintf (stderr, "   or:  ... | pnm2png [options]\n");
+  fprintf (stderr, "Options:\n");
+  fprintf (stderr, "   -i[nterlace]   write png-file with interlacing on\n");
+  fprintf (stderr, "   -a[lpha] <file>.pgm read PNG alpha channel as pgm-file\n");
+  fprintf (stderr, "   -h | -?  print this help-information\n");
+}
+/*
+ *  pnm2png
+ */
+BOOL pnm2png (FILE *pnm_file, FILE *png_file, FILE *alpha_file, BOOL interlace, BOOL alpha)
+{
+  png_struct    *png_ptr = NULL;
+  png_info      *info_ptr = NULL;
+  png_byte      *png_pixels = NULL;
+  png_byte      **row_pointers = NULL;
+  png_byte      *pix_ptr = NULL;
+  png_uint_32   row_bytes;
+  char          type_token[16];
+  char          width_token[16];
+  char          height_token[16];
+  char          maxval_token[16];
+  int           color_type;
+  png_uint_32   width, alpha_width;
+  png_uint_32   height, alpha_height;
+  png_uint_32   maxval;
+  int           bit_depth = 0;
+  int           channels;
+  int           alpha_depth = 0;
+  int           alpha_present;
+  int           row, col;
+  BOOL          raw, alpha_raw = FALSE;
+  png_uint_32   tmp16;
+  int           i;
+  /* read header of PNM file */
+  get_token(pnm_file, type_token);
+  if (type_token[0] != 'P')
+  {
+    return FALSE;
+  }
+  else if ((type_token[1] == '1') || (type_token[1] == '4'))
+  {
+    raw = (type_token[1] == '4');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    bit_depth = 1;
+  }
+  else if ((type_token[1] == '2') || (type_token[1] == '5'))
+  {
+    raw = (type_token[1] == '5');
+    color_type = PNG_COLOR_TYPE_GRAY;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &width);
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &height);
+    get_token(pnm_file, maxval_token);
+    sscanf (maxval_token, "%lu", &maxval);
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else /* if (maxval <= 65535) */
+      bit_depth = 16;
+  }
+  else if ((type_token[1] == '3') || (type_token[1] == '6'))
+  {
+    raw = (type_token[1] == '6');
+    color_type = PNG_COLOR_TYPE_RGB;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &width);
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &height);
+    get_token(pnm_file, maxval_token);
+    sscanf (maxval_token, "%lu", &maxval);
+    if (maxval <= 1)
+      bit_depth = 1;
+    else if (maxval <= 3)
+      bit_depth = 2;
+    else if (maxval <= 15)
+      bit_depth = 4;
+    else if (maxval <= 255)
+      bit_depth = 8;
+    else /* if (maxval <= 65535) */
+      bit_depth = 16;
+  }
+  else
+  {
+    return FALSE;
+  }
+  /* read header of PGM file with alpha channel */
+  if (alpha)
+  {
+    if (color_type == PNG_COLOR_TYPE_GRAY)
+      color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+    if (color_type == PNG_COLOR_TYPE_RGB)
+      color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+    get_token(alpha_file, type_token);
+    if (type_token[0] != 'P')
+    {
+      return FALSE;
+    }
+    else if ((type_token[1] == '2') || (type_token[1] == '5'))
+    {
+      alpha_raw = (type_token[1] == '5');
+      get_token(alpha_file, width_token);
+      sscanf (width_token, "%lu", &alpha_width);
+      if (alpha_width != width)
+        return FALSE;
+      get_token(alpha_file, height_token);
+      sscanf (height_token, "%lu", &alpha_height);
+      if (alpha_height != height)
+        return FALSE;
+      get_token(alpha_file, maxval_token);
+      sscanf (maxval_token, "%lu", &maxval);
+      if (maxval <= 1)
+        alpha_depth = 1;
+      else if (maxval <= 3)
+        alpha_depth = 2;
+      else if (maxval <= 15)
+        alpha_depth = 4;
+      else if (maxval <= 255)
+        alpha_depth = 8;
+      else /* if (maxval <= 65535) */
+        alpha_depth = 16;
+      if (alpha_depth != bit_depth)
+        return FALSE;
+    }
+    else
+    {
+      return FALSE;
+    }
+  } /* end if alpha */
+  /* calculate the number of channels and store alpha-presence */
+  if (color_type == PNG_COLOR_TYPE_GRAY)
+    channels = 1;
+  else if (color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+    channels = 2;
+  else if (color_type == PNG_COLOR_TYPE_RGB)
+    channels = 3;
+  else if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+    channels = 4;
+  else
+    channels = 0; /* should not happen */
+  alpha_present = (channels - 1) % 2;
+  /* row_bytes is the width x number of channels x (bit-depth / 8) */
+  row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+  if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
+    return FALSE;
+  /* read data from PNM file */
+  pix_ptr = png_pixels;
+  for (row = 0; row < height; row++)
+  {
+    for (col = 0; col < width; col++)
+    {
+      for (i = 0; i < (channels - alpha_present); i++)
+      {
+        if (raw)
+          *pix_ptr++ = get_data (pnm_file, bit_depth);
+        else
+          if (bit_depth <= 8)
+            *pix_ptr++ = get_value (pnm_file, bit_depth);
+          else
+          {
+            tmp16 = get_value (pnm_file, bit_depth);
+            *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+            pix_ptr++;
+            *pix_ptr = (png_byte) (tmp16 & 0xFF);
+            pix_ptr++;
+          }
+      }
+      if (alpha) /* read alpha-channel from pgm file */
+      {
+        if (alpha_raw)
+          *pix_ptr++ = get_data (alpha_file, alpha_depth);
+        else
+          if (alpha_depth <= 8)
+            *pix_ptr++ = get_value (alpha_file, bit_depth);
+          else
+          {
+            tmp16 = get_value (alpha_file, bit_depth);
+            *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+            *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+          }
+      } /* if alpha */
+    } /* end for col */
+  } /* end for row */
+  /* prepare the standard PNG structures */
+  png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+  if (!png_ptr)
+  {
+    return FALSE;
+  }
+  info_ptr = png_create_info_struct (png_ptr);
+  if (!info_ptr)
+  {
+    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+    return FALSE;
+  }
+  /* setjmp() must be called in every function that calls a PNG-reading libpng function */
+  if (setjmp (png_jmpbuf(png_ptr)))
+  {
+    png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+    return FALSE;
+  }
+  /* initialize the png structure */
+  png_init_io (png_ptr, png_file);
+  /* we're going to write more or less the same PNG as the input file */
+  png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
+    (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
+    PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+  /* write the file header information */
+  png_write_info (png_ptr, info_ptr);
+  /* if needed we will allocate memory for an new array of row-pointers */
+  if (row_pointers == (unsigned char**) NULL)
+  {
+    if ((row_pointers = (png_byte **) malloc (height * sizeof (png_bytep))) == NULL)
+    {
+      png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+      return FALSE;
+    }
+  }
+  /* set the individual row_pointers to point at the correct offsets */
+  for (i = 0; i < (height); i++)
+    row_pointers[i] = png_pixels + i * row_bytes;
+  /* write out the entire image data in one call */
+  png_write_image (png_ptr, row_pointers);
+  /* write the additional chuncks to the PNG file (not really needed) */
+  png_write_end (png_ptr, info_ptr);
+  /* clean up after the write, and free any memory allocated */
+  png_destroy_write_struct (&png_ptr, (png_infopp) NULL);
+  if (row_pointers != (unsigned char**) NULL)
+    free (row_pointers);
+  if (png_pixels != (unsigned char*) NULL)
+    free (png_pixels);
+  return TRUE;
+} /* end of pnm2png */
+/*
+ * get_token() - gets the first string after whitespace
+ */
+void get_token(FILE *pnm_file, char *token)
+{
+  int i = 0;
+  /* remove white-space */
+  do
+  {
+    token[i] = (unsigned char) fgetc (pnm_file);
+  }
+  while ((token[i] == '\n') || (token[i] == '\r') || (token[i] == ' '));
+  /* read string */
+  do
+  {
+    i++;
+    token[i] = (unsigned char) fgetc (pnm_file);
+  }
+  while ((token[i] != '\n') && (token[i] != '\r') && (token[i] != ' '));
+  token[i] = '\0';
+  return;
+}
+/*
+ * get_data() - takes first byte and converts into next pixel value,
+ *        taking as much bits as defined by bit-depth and
+ *        using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+png_uint_32 get_data (FILE *pnm_file, int depth)
+{
+  static int bits_left = 0;
+  static int old_value = 0;
+  static int mask = 0;
+  int i;
+  png_uint_32 ret_value;
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask >> 1) | 0x80;
+  if (bits_left <= 0)
+  {
+    old_value = fgetc (pnm_file);
+    bits_left = 8;
+  }
+  ret_value = old_value & mask;
+  for (i = 1; i < (8 / depth); i++)
+    ret_value = ret_value || (ret_value >> depth);
+  old_value = (old_value << depth) & 0xFF;
+  bits_left -= depth;
+  return ret_value;
+}
+/*
+ * get_value() - takes first (numeric) string and converts into number,
+ *         using the bit-depth to fill up a byte (0Ah -> AAh)
+ */
+png_uint_32 get_value (FILE *pnm_file, int depth)
+{
+  static png_uint_32 mask = 0;
+  png_byte token[16];
+  png_uint_32 ret_value;
+  int i = 0;
+  if (mask == 0)
+    for (i = 0; i < depth; i++)
+      mask = (mask << 1) | 0x01;
+  get_token (pnm_file, (char *) token);
+  sscanf ((const char *) token, "%lu", &ret_value);
+  ret_value &= mask;
+  if (depth < 8)
+    for (i = 0; i < (8 / depth); i++)
+      ret_value = (ret_value << depth) || ret_value;
+  return ret_value;
+}
+/* end of source */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.sh b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.sh
new file mode 100755
index 0000000..975f047
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngminus/pnm2png.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# -- grayscale
+./pnm2png basn0g01.pgm basn0g01.png
+./pnm2png basn0g02.pgm basn0g02.png
+./pnm2png basn0g04.pgm basn0g04.png
+./pnm2png basn0g08.pgm basn0g08.png
+./pnm2png basn0g16.pgm basn0g16.png
+# -- full-color
+./pnm2png basn2c08.ppm basn2c08.png
+./pnm2png basn2c16.ppm basn2c16.png
+# -- palletted
+./pnm2png basn3p01.ppm basn3p01.png
+./pnm2png basn3p02.ppm basn3p02.png
+./pnm2png basn3p04.ppm basn3p04.png
+./pnm2png basn3p08.ppm basn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn4a08.pgm basn4a08.png
+./pnm2png -alpha basn6a16.pgm basn4a16.pgm basn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha basn6a08.pgm basn6a08.ppm basn6a08.png
+./pnm2png -alpha basn6a16.pgm basn6a16.ppm basn6a16.png
+# -- grayscale
+./pnm2png rawn0g01.pgm rawn0g01.png
+./pnm2png rawn0g02.pgm rawn0g02.png
+./pnm2png rawn0g04.pgm rawn0g04.png
+./pnm2png rawn0g08.pgm rawn0g08.png
+./pnm2png rawn0g16.pgm rawn0g16.png
+# -- full-color
+./pnm2png rawn2c08.ppm rawn2c08.png
+./pnm2png rawn2c16.ppm rawn2c16.png
+# -- palletted
+./pnm2png rawn3p01.ppm rawn3p01.png
+./pnm2png rawn3p02.ppm rawn3p02.png
+./pnm2png rawn3p04.ppm rawn3p04.png
+./pnm2png rawn3p08.ppm rawn3p08.png
+# -- gray with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn4a08.pgm rawn4a08.png
+./pnm2png -alpha rawn6a16.pgm rawn4a16.pgm rawn4a16.png
+# -- color with alpha-channel
+./pnm2png -alpha rawn6a08.pgm rawn6a08.ppm rawn6a08.png
+./pnm2png -alpha rawn6a16.pgm rawn6a16.ppm rawn6a16.png
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngsuite/basn0g01.png b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/pngsuite/basn0g01.png
new file mode 100644
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diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.c
new file mode 100644
index 0000000..f3e440a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.c
@@ -0,0 +1,450 @@
+/*-------------------------------------
+ *  PNGFILE.C -- Image File Functions
+ *-------------------------------------
+ *
+ * Copyright 2000, Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+#include <windows.h>
+#include <commdlg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "png.h"
+#include "pngfile.h"
+#include "cexcept.h"
+define_exception_type(const char *);
+extern struct exception_context the_exception_context[1];
+struct exception_context the_exception_context[1];
+png_const_charp msg;
+static OPENFILENAME ofn;
+static png_structp png_ptr = NULL;
+static png_infop info_ptr = NULL;
+/* cexcept interface */
+static void
+png_cexcept_error(png_structp png_ptr, png_const_charp msg)
+{
+   if(png_ptr)
+     ;
+#ifdef PNG_CONSOLE_IO_SUPPORTED
+   fprintf(stderr, "libpng error: %s\n", msg);
+#endif
+   {
+      Throw msg;
+   }
+}
+/* Windows open-file functions */
+void PngFileInitialize (HWND hwnd)
+{
+    static TCHAR szFilter[] = TEXT ("PNG Files (*.PNG)\0*.png\0")
+        TEXT ("All Files (*.*)\0*.*\0\0");
+    ofn.lStructSize       = sizeof (OPENFILENAME);
+    ofn.hwndOwner         = hwnd;
+    ofn.hInstance         = NULL;
+    ofn.lpstrFilter       = szFilter;
+    ofn.lpstrCustomFilter = NULL;
+    ofn.nMaxCustFilter    = 0;
+    ofn.nFilterIndex      = 0;
+    ofn.lpstrFile         = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFile          = MAX_PATH;
+    ofn.lpstrFileTitle    = NULL;          /* Set in Open and Close functions */
+    ofn.nMaxFileTitle     = MAX_PATH;
+    ofn.lpstrInitialDir   = NULL;
+    ofn.lpstrTitle        = NULL;
+    ofn.Flags             = 0;             /* Set in Open and Close functions */
+    ofn.nFileOffset       = 0;
+    ofn.nFileExtension    = 0;
+    ofn.lpstrDefExt       = TEXT ("png");
+    ofn.lCustData         = 0;
+    ofn.lpfnHook          = NULL;
+    ofn.lpTemplateName    = NULL;
+}
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY;
+    return GetOpenFileName (&ofn);
+}
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName)
+{
+    ofn.hwndOwner         = hwnd;
+    ofn.lpstrFile         = pstrFileName;
+    ofn.lpstrFileTitle    = pstrTitleName;
+    ofn.Flags             = OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT;
+    return GetSaveFileName (&ofn);
+}
+/* PNG image handler functions */
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData,
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor)
+{
+    static FILE        *pfFile;
+    png_byte            pbSig[8];
+    int                 iBitDepth;
+    int                 iColorType;
+    double              dGamma;
+    png_color_16       *pBackground;
+    png_uint_32         ulChannels;
+    png_uint_32         ulRowBytes;
+    png_byte           *pbImageData = *ppbImageData;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+    /* open the PNG input file */
+    if (!pstrFileName)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+    if (!(pfFile = fopen(pstrFileName, "rb")))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+    /* first check the eight byte PNG signature */
+    fread(pbSig, 1, 8, pfFile);
+    if (png_sig_cmp(pbSig, 0, 8))
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+    /* create the two png(-info) structures */
+    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr)
+    {
+        png_destroy_read_struct(&png_ptr, NULL, NULL);
+        *ppbImageData = pbImageData = NULL;
+        return FALSE;
+    }
+    Try
+    {
+        /* initialize the png structure */
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_read_fn(png_ptr, (png_voidp)pfFile, png_read_data);
+#endif
+        png_set_sig_bytes(png_ptr, 8);
+        /* read all PNG info up to image data */
+        png_read_info(png_ptr, info_ptr);
+        /* get width, height, bit-depth and color-type */
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+        /* expand images of all color-type and bit-depth to 3x8-bit RGB */
+        /* let the library process alpha, transparency, background, etc. */
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+    if (iBitDepth == 16)
+#  ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+        png_set_scale_16(png_ptr);
+#  else
+        png_set_strip_16(png_ptr);
+#  endif
+#endif
+        if (iColorType == PNG_COLOR_TYPE_PALETTE)
+            png_set_expand(png_ptr);
+        if (iBitDepth < 8)
+            png_set_expand(png_ptr);
+        if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+            png_set_expand(png_ptr);
+        if (iColorType == PNG_COLOR_TYPE_GRAY ||
+            iColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
+            png_set_gray_to_rgb(png_ptr);
+        /* set the background color to draw transparent and alpha images over */
+        if (png_get_bKGD(png_ptr, info_ptr, &pBackground))
+        {
+            png_set_background(png_ptr, pBackground, PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+            pBkgColor->red   = (byte) pBackground->red;
+            pBkgColor->green = (byte) pBackground->green;
+            pBkgColor->blue  = (byte) pBackground->blue;
+        }
+        else
+        {
+            pBkgColor = NULL;
+        }
+        /* if required set gamma conversion */
+        if (png_get_gAMA(png_ptr, info_ptr, &dGamma))
+            png_set_gamma(png_ptr, (double) 2.2, dGamma);
+        /* after the transformations are registered, update info_ptr data */
+        png_read_update_info(png_ptr, info_ptr);
+        /* get again width, height and the new bit-depth and color-type */
+        png_get_IHDR(png_ptr, info_ptr, piWidth, piHeight, &iBitDepth,
+            &iColorType, NULL, NULL, NULL);
+        /* row_bytes is the width x number of channels */
+        ulRowBytes = png_get_rowbytes(png_ptr, info_ptr);
+        ulChannels = png_get_channels(png_ptr, info_ptr);
+        *piChannels = ulChannels;
+        /* now we can allocate memory to store the image */
+        if (pbImageData)
+        {
+            free (pbImageData);
+            pbImageData = NULL;
+        }
+        if ((pbImageData = (png_byte *) malloc(ulRowBytes * (*piHeight)
+                            * sizeof(png_byte))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+        *ppbImageData = pbImageData;
+        /* and allocate memory for an array of row-pointers */
+        if ((ppbRowPointers = (png_bytepp) malloc((*piHeight)
+                            * sizeof(png_bytep))) == NULL)
+        {
+            png_error(png_ptr, "Visual PNG: out of memory");
+        }
+        /* set the individual row-pointers to point at the correct offsets */
+        for (i = 0; i < (*piHeight); i++)
+            ppbRowPointers[i] = pbImageData + i * ulRowBytes;
+        /* now we can go ahead and just read the whole image */
+        png_read_image(png_ptr, ppbRowPointers);
+        /* read the additional chunks in the PNG file (not really needed) */
+        png_read_end(png_ptr, NULL);
+        /* and we're done */
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+        /* yepp, done */
+    }
+    Catch (msg)
+    {
+        png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+        *ppbImageData = pbImageData = NULL;
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+        fclose(pfFile);
+        return FALSE;
+    }
+    fclose (pfFile);
+    return TRUE;
+}
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color bkgColor)
+{
+    const int           ciBitDepth = 8;
+    const int           ciChannels = 3;
+    static FILE        *pfFile;
+    png_uint_32         ulRowBytes;
+    static png_byte   **ppbRowPointers = NULL;
+    int                 i;
+    /* open the PNG output file */
+    if (!pstrFileName)
+        return FALSE;
+    if (!(pfFile = fopen(pstrFileName, "wb")))
+        return FALSE;
+    /* prepare the standard PNG structures */
+    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL,
+      (png_error_ptr)png_cexcept_error, (png_error_ptr)NULL);
+    if (!png_ptr)
+    {
+        fclose(pfFile);
+        return FALSE;
+    }
+    info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        fclose(pfFile);
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+        return FALSE;
+    }
+    Try
+    {
+        /* initialize the png structure */
+#ifdef PNG_STDIO_SUPPORTED
+        png_init_io(png_ptr, pfFile);
+#else
+        png_set_write_fn(png_ptr, (png_voidp)pfFile, png_write_data, png_flush);
+#endif
+        /* we're going to write a very simple 3x8-bit RGB image */
+        png_set_IHDR(png_ptr, info_ptr, iWidth, iHeight, ciBitDepth,
+            PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE,
+            PNG_FILTER_TYPE_BASE);
+        /* write the file header information */
+        png_write_info(png_ptr, info_ptr);
+        /* swap the BGR pixels in the DiData structure to RGB */
+        png_set_bgr(png_ptr);
+        /* row_bytes is the width x number of channels */
+        ulRowBytes = iWidth * ciChannels;
+        /* we can allocate memory for an array of row-pointers */
+        if ((ppbRowPointers = (png_bytepp) malloc(iHeight * sizeof(png_bytep))) == NULL)
+            Throw "Visualpng: Out of memory";
+        /* set the individual row-pointers to point at the correct offsets */
+        for (i = 0; i < iHeight; i++)
+            ppbRowPointers[i] = pDiData + i * (((ulRowBytes + 3) >> 2) << 2);
+        /* write out the entire image data in one call */
+        png_write_image (png_ptr, ppbRowPointers);
+        /* write the additional chunks to the PNG file (not really needed) */
+        png_write_end(png_ptr, info_ptr);
+        /* and we're done */
+        free (ppbRowPointers);
+        ppbRowPointers = NULL;
+        /* clean up after the write, and free any memory allocated */
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+        /* yepp, done */
+    }
+    Catch (msg)
+    {
+        png_destroy_write_struct(&png_ptr, (png_infopp) NULL);
+        if(ppbRowPointers)
+            free (ppbRowPointers);
+        fclose(pfFile);
+        return FALSE;
+    }
+    fclose (pfFile);
+    return TRUE;
+}
+#ifndef PNG_STDIO_SUPPORTED
+static void
+png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_size_t check;
+   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+   check = (png_size_t)fread(data, (png_size_t)1, length,
+      (FILE *)png_ptr->io_ptr);
+   if (check != length)
+   {
+      png_error(png_ptr, "Read Error");
+   }
+}
+static void
+png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_uint_32 check;
+   check = fwrite(data, 1, length, (FILE *)(png_ptr->io_ptr));
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+}
+static void
+png_flush(png_structp png_ptr)
+{
+   FILE *io_ptr;
+   io_ptr = (FILE *)CVT_PTR((png_ptr->io_ptr));
+   if (io_ptr != NULL)
+      fflush(io_ptr);
+}
+#endif
+/*-----------------
+ *  end of source
+ *-----------------
+ */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.h
new file mode 100644
index 0000000..66f8472
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/PngFile.h
@@ -0,0 +1,30 @@
+/*------------------------------------------*/
+/*  PNGFILE.H -- Header File for pngfile.c*/
+/*------------------------------------------*/
+/* Copyright 2000, Willem van Schaik.*/
+/* This code is released under the libpng license.*/
+/* For conditions of distribution and use, see the disclaimer*/
+/* and license in png.h*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+void PngFileInitialize (HWND hwnd) ;
+BOOL PngFileOpenDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+BOOL PngFileSaveDlg (HWND hwnd, PTSTR pstrFileName, PTSTR pstrTitleName) ;
+BOOL PngLoadImage (PTSTR pstrFileName, png_byte **ppbImageData, 
+                   int *piWidth, int *piHeight, int *piChannels, png_color *pBkgColor);
+BOOL PngSaveImage (PTSTR pstrFileName, png_byte *pDiData,
+                   int iWidth, int iHeight, png_color BkgColor);
+#ifndef PNG_STDIO_SUPPORTED
+static void png_read_data(png_structp png_ptr, png_bytep data, png_size_t length);
+static void png_write_data(png_structp png_ptr, png_bytep data, png_size_t length);
+static void png_flush(png_structp png_ptr);
+#endif
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/README.txt b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/README.txt
new file mode 100644
index 0000000..7291bb2
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/README.txt
@@ -0,0 +1,61 @@
+Microsoft Developer Studio Build File, Format Version 6.00 for VisualPng
+------------------------------------------------------------------------
+Copyright 2000, Willem van Schaik.
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer
+and license in png.h
+As a PNG .dll demo VisualPng is finished. More features would only hinder
+the program's objective. However, further extensions (like support for other
+graphics formats) are in development. To get these, or for pre-compiled
+binaries, go to "http://www.schaik.com/png/visualpng.html".
+------------------------------------------------------------------------
+Assumes that
+   libpng DLLs and LIBs are in ..\..\projects\msvc\win32\libpng
+   zlib DLLs and LIBs are in   ..\..\projects\msvc\win32\zlib
+   libpng header files are in  ..\..\..\libpng
+   zlib header files are in    ..\..\..\zlib
+   the pngsuite images are in  ..\pngsuite
+To build:
+1) On the main menu Select "Build|Set Active configuration".
+   Choose the configuration that corresponds to the library you want to test.
+   This library must have been built using the libpng MS project located in
+   the "..\..\mscv" subdirectory.
+2) Select "Build|Clean"
+3) Select "Build|Rebuild All"
+4) After compiling and linking VisualPng will be started to view an image
+   from the PngSuite directory.  Press Ctrl-N (and Ctrl-V) for other images.
+To install:
+When distributing VisualPng (or a further development) the following options
+are available:
+1) Build the program with the configuration "Win32 LIB" and you only need to
+   include the executable from the ./lib directory in your distribution.
+2) Build the program with the configuration "Win32 DLL" and you need to put
+   in your distribution the executable from the ./dll directory and the dll's
+   libpng1.dll, zlib.dll and msvcrt.dll.  These need to be in the user's PATH.
+Willem van Schaik
+Calgary, June 6th 2000
+P.S. VisualPng was written based on preliminary work of:
+    - Simon-Pierre Cadieux
+    - Glenn Randers-Pehrson
+    - Greg Roelofs
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.c b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.c
new file mode 100644
index 0000000..e672ce0
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.c
@@ -0,0 +1,969 @@
+/*------------------------------------
+ *  VisualPng.C -- Shows a PNG image
+ *------------------------------------
+ *
+ * Copyright 2000, Willem van Schaik.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+/* switches */
+/* defines */
+#define PROGNAME  "VisualPng"
+#define LONGNAME  "Win32 Viewer for PNG-files"
+#define VERSION   "1.0 of 2000 June 07"
+/* constants */
+#define MARGIN 8
+/* standard includes */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <windows.h>
+/* application includes */
+#include "png.h"
+#include "pngfile.h"
+#include "resource.h"
+/* macros */
+/* function prototypes */
+LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM);
+BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent);
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+        int *pFileIndex);
+BOOL SearchPngList (TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName);
+BOOL LoadImageFile(HWND hwnd, PTSTR pstrPathName,
+        png_byte **ppbImage, int *pxImgSize, int *pyImgSize, int *piChannels,
+        png_color *pBkgColor);
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+BOOL InitBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize);
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched);
+/* a few global variables */
+static char *szProgName = PROGNAME;
+static char *szAppName = LONGNAME;
+static char *szIconName = PROGNAME;
+static char szCmdFileName [MAX_PATH];
+/* MAIN routine */
+int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
+                    PSTR szCmdLine, int iCmdShow)
+{
+    HACCEL   hAccel;
+    HWND     hwnd;
+    MSG      msg;
+    WNDCLASS wndclass;
+    int ixBorders, iyBorders;
+    wndclass.style         = CS_HREDRAW | CS_VREDRAW;
+    wndclass.lpfnWndProc   = WndProc;
+    wndclass.cbClsExtra    = 0;
+    wndclass.cbWndExtra    = 0;
+    wndclass.hInstance     = hInstance;
+    wndclass.hIcon         = LoadIcon (hInstance, szIconName) ;
+    wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW);
+    wndclass.hbrBackground = NULL; /* (HBRUSH) GetStockObject (GRAY_BRUSH); */
+    wndclass.lpszMenuName  = szProgName;
+    wndclass.lpszClassName = szProgName;
+    if (!RegisterClass (&wndclass))
+    {
+        MessageBox (NULL, TEXT ("Error: this program requires Windows NT!"),
+            szProgName, MB_ICONERROR);
+        return 0;
+    }
+    /* if filename given on commandline, store it */
+    if ((szCmdLine != NULL) && (*szCmdLine != '\0'))
+        if (szCmdLine[0] == '"')
+            strncpy (szCmdFileName, szCmdLine + 1, strlen(szCmdLine) - 2);
+        else
+            strcpy (szCmdFileName, szCmdLine);
+    else
+        strcpy (szCmdFileName, "");
+    /* calculate size of window-borders */
+    ixBorders = 2 * (GetSystemMetrics (SM_CXBORDER) +
+                     GetSystemMetrics (SM_CXDLGFRAME));
+    iyBorders = 2 * (GetSystemMetrics (SM_CYBORDER) +
+                     GetSystemMetrics (SM_CYDLGFRAME)) +
+                     GetSystemMetrics (SM_CYCAPTION) +
+                     GetSystemMetrics (SM_CYMENUSIZE) +
+                     1; /* WvS: don't ask me why?  */
+    hwnd = CreateWindow (szProgName, szAppName,
+        WS_OVERLAPPEDWINDOW,
+        CW_USEDEFAULT, CW_USEDEFAULT,
+        512 + 2 * MARGIN + ixBorders, 384 + 2 * MARGIN + iyBorders,
+/*      CW_USEDEFAULT, CW_USEDEFAULT, */
+        NULL, NULL, hInstance, NULL);
+    ShowWindow (hwnd, iCmdShow);
+    UpdateWindow (hwnd);
+    hAccel = LoadAccelerators (hInstance, szProgName);
+    while (GetMessage (&msg, NULL, 0, 0))
+    {
+        if (!TranslateAccelerator (hwnd, hAccel, &msg))
+        {
+            TranslateMessage (&msg);
+            DispatchMessage (&msg);
+        }
+    }
+    return msg.wParam;
+}
+LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,
+        LPARAM lParam)
+{
+    static HINSTANCE          hInstance ;
+    static HDC                hdc;
+    static PAINTSTRUCT        ps;
+    static HMENU              hMenu;
+    static BITMAPFILEHEADER  *pbmfh;
+    static BITMAPINFOHEADER  *pbmih;
+    static BYTE              *pbImage;
+    static int                cxWinSize, cyWinSize;
+    static int                cxImgSize, cyImgSize;
+    static int                cImgChannels;
+    static png_color          bkgColor = {127, 127, 127};
+    static BOOL               bStretched = TRUE;
+    static BYTE              *pDib = NULL;
+    static BYTE              *pDiData = NULL;
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szTitleName [MAX_PATH];
+    static TCHAR             *pPngFileList = NULL;
+    static int                iPngFileCount;
+    static int                iPngFileIndex;
+    BOOL                      bOk;
+    switch (message)
+    {
+    case WM_CREATE:
+        hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
+        PngFileInitialize (hwnd);
+        strcpy (szImgPathName, "");
+        /* in case we process file given on command-line */
+        if (szCmdFileName[0] != '\0')
+        {
+            strcpy (szImgPathName, szCmdFileName);
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+            /* load the image from file */
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+            /* invalidate the client area for later update */
+            InvalidateRect (hwnd, NULL, TRUE);
+            /* display the PNG into the DIBitmap */
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+        }
+        return 0;
+    case WM_SIZE:
+        cxWinSize = LOWORD (lParam);
+        cyWinSize = HIWORD (lParam);
+        /* invalidate the client area for later update */
+        InvalidateRect (hwnd, NULL, TRUE);
+        /* display the PNG into the DIBitmap */
+        DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+        return 0;
+    case WM_INITMENUPOPUP:
+        hMenu = GetMenu (hwnd);
+        if (pbImage)
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_ENABLED);
+        else
+            EnableMenuItem (hMenu, IDM_FILE_SAVE, MF_GRAYED);
+        return 0;
+    case WM_COMMAND:
+        hMenu = GetMenu (hwnd);
+        switch (LOWORD (wParam))
+        {
+        case IDM_FILE_OPEN:
+            /* show the File Open dialog box */
+            if (!PngFileOpenDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+            /* read the other png-files in the directory for later */
+            /* next/previous commands */
+            BuildPngList (szImgPathName, &pPngFileList, &iPngFileCount,
+                          &iPngFileIndex);
+            /* load the image from file */
+            if (!LoadImageFile (hwnd, szImgPathName,
+                &pbImage, &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                return 0;
+            /* invalidate the client area for later update */
+            InvalidateRect (hwnd, NULL, TRUE);
+            /* display the PNG into the DIBitmap */
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            return 0;
+        case IDM_FILE_SAVE:
+            /* show the File Save dialog box */
+            if (!PngFileSaveDlg (hwnd, szImgPathName, szTitleName))
+                return 0;
+            /* save the PNG to a disk file */
+            SetCursor (LoadCursor (NULL, IDC_WAIT));
+            ShowCursor (TRUE);
+            bOk = PngSaveImage (szImgPathName, pDiData, cxWinSize, cyWinSize,
+                  bkgColor);
+            ShowCursor (FALSE);
+            SetCursor (LoadCursor (NULL, IDC_ARROW));
+            if (!bOk)
+                MessageBox (hwnd, TEXT ("Error in saving the PNG image"),
+                szProgName, MB_ICONEXCLAMATION | MB_OK);
+            return 0;
+        case IDM_FILE_NEXT:
+            /* read next entry in the directory */
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                NULL, szImgPathName))
+            {
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+                /* load the image from file */
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage,
+                        &cxImgSize, &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+                /* invalidate the client area for later update */
+                InvalidateRect (hwnd, NULL, TRUE);
+                /* display the PNG into the DIBitmap */
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+            return 0;
+        case IDM_FILE_PREVIOUS:
+            /* read previous entry in the directory */
+            if (SearchPngList (pPngFileList, iPngFileCount, &iPngFileIndex,
+                szImgPathName, NULL))
+            {
+                if (strcmp (szImgPathName, "") == 0)
+                    return 0;
+                /* load the image from file */
+                if (!LoadImageFile (hwnd, szImgPathName, &pbImage, &cxImgSize,
+                    &cyImgSize, &cImgChannels, &bkgColor))
+                    return 0;
+                /* invalidate the client area for later update */
+                InvalidateRect (hwnd, NULL, TRUE);
+                /* display the PNG into the DIBitmap */
+                DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                    pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            }
+            return 0;
+        case IDM_FILE_EXIT:
+            /* more cleanup needed... */
+            /* free image buffer */
+            if (pDib != NULL)
+            {
+                free (pDib);
+                pDib = NULL;
+            }
+            /* free file-list */
+            if (pPngFileList != NULL)
+            {
+                free (pPngFileList);
+                pPngFileList = NULL;
+            }
+            /* let's go ... */
+            exit (0);
+            return 0;
+        case IDM_OPTIONS_STRETCH:
+            bStretched = !bStretched;
+            if (bStretched)
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_CHECKED);
+            else
+                CheckMenuItem (hMenu, IDM_OPTIONS_STRETCH, MF_UNCHECKED);
+            /* invalidate the client area for later update */
+            InvalidateRect (hwnd, NULL, TRUE);
+            /* display the PNG into the DIBitmap */
+            DisplayImage (hwnd, &pDib, &pDiData, cxWinSize, cyWinSize,
+                pbImage, cxImgSize, cyImgSize, cImgChannels, bStretched);
+            return 0;
+        case IDM_HELP_ABOUT:
+            DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc) ;
+            return 0;
+        } /* end switch */
+        break;
+    case WM_PAINT:
+        hdc = BeginPaint (hwnd, &ps);
+        if (pDib)
+            SetDIBitsToDevice (hdc, 0, 0, cxWinSize, cyWinSize, 0, 0,
+                0, cyWinSize, pDiData, (BITMAPINFO *) pDib, DIB_RGB_COLORS);
+        EndPaint (hwnd, &ps);
+        return 0;
+    case WM_DESTROY:
+        if (pbmfh)
+        {
+            free (pbmfh);
+            pbmfh = NULL;
+        }
+        PostQuitMessage (0);
+        return 0;
+    }
+    return DefWindowProc (hwnd, message, wParam, lParam);
+}
+BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message,
+                            WPARAM wParam, LPARAM lParam)
+{
+     switch (message)
+     {
+     case WM_INITDIALOG :
+          ShowWindow (hDlg, SW_HIDE);
+          CenterAbout (hDlg, GetWindow (hDlg, GW_OWNER));
+          ShowWindow (hDlg, SW_SHOW);
+          return TRUE ;
+     case WM_COMMAND :
+          switch (LOWORD (wParam))
+          {
+          case IDOK :
+          case IDCANCEL :
+               EndDialog (hDlg, 0) ;
+               return TRUE ;
+          }
+          break ;
+     }
+     return FALSE ;
+}
+/*---------------
+ *  CenterAbout
+ *---------------
+ */
+BOOL CenterAbout (HWND hwndChild, HWND hwndParent)
+{
+   RECT    rChild, rParent, rWorkArea;
+   int     wChild, hChild, wParent, hParent;
+   int     xNew, yNew;
+   BOOL  bResult;
+   /* Get the Height and Width of the child window */
+   GetWindowRect (hwndChild, &rChild);
+   wChild = rChild.right - rChild.left;
+   hChild = rChild.bottom - rChild.top;
+   /* Get the Height and Width of the parent window */
+   GetWindowRect (hwndParent, &rParent);
+   wParent = rParent.right - rParent.left;
+   hParent = rParent.bottom - rParent.top;
+   /* Get the limits of the 'workarea' */
+   bResult = SystemParametersInfo(
+      SPI_GETWORKAREA,  /* system parameter to query or set */
+      sizeof(RECT),
+      &rWorkArea,
+      0);
+   if (!bResult) {
+      rWorkArea.left = rWorkArea.top = 0;
+      rWorkArea.right = GetSystemMetrics(SM_CXSCREEN);
+      rWorkArea.bottom = GetSystemMetrics(SM_CYSCREEN);
+   }
+   /* Calculate new X position, then adjust for workarea */
+   xNew = rParent.left + ((wParent - wChild) /2);
+   if (xNew < rWorkArea.left) {
+      xNew = rWorkArea.left;
+   } else if ((xNew+wChild) > rWorkArea.right) {
+      xNew = rWorkArea.right - wChild;
+   }
+   /* Calculate new Y position, then adjust for workarea */
+   yNew = rParent.top  + ((hParent - hChild) /2);
+   if (yNew < rWorkArea.top) {
+      yNew = rWorkArea.top;
+   } else if ((yNew+hChild) > rWorkArea.bottom) {
+      yNew = rWorkArea.bottom - hChild;
+   }
+   /* Set it, and return */
+   return SetWindowPos (hwndChild, NULL, xNew, yNew, 0, 0, SWP_NOSIZE |
+          SWP_NOZORDER);
+}
+/*----------------
+ *  BuildPngList
+ *----------------
+ */
+BOOL BuildPngList (PTSTR pstrPathName, TCHAR **ppFileList, int *pFileCount,
+     int *pFileIndex)
+{
+    static TCHAR              szImgPathName [MAX_PATH];
+    static TCHAR              szImgFileName [MAX_PATH];
+    static TCHAR              szImgFindName [MAX_PATH];
+    WIN32_FIND_DATA           finddata;
+    HANDLE                    hFind;
+    static TCHAR              szTmp [MAX_PATH];
+    BOOL                      bOk;
+    int                       i, ii;
+    int                       j, jj;
+    /* free previous file-list */
+    if (*ppFileList != NULL)
+    {
+        free (*ppFileList);
+        *ppFileList = NULL;
+    }
+    /* extract foldername, filename and search-name */
+    strcpy (szImgPathName, pstrPathName);
+    strcpy (szImgFileName, strrchr (pstrPathName, '\\') + 1);
+    strcpy (szImgFindName, szImgPathName);
+    *(strrchr (szImgFindName, '\\') + 1) = '\0';
+    strcat (szImgFindName, "*.png");
+    /* first cycle: count number of files in directory for memory allocation */
+    *pFileCount = 0;
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+    while (bOk)
+    {
+        *pFileCount += 1;
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+    /* allocation memory for file-list */
+    *ppFileList = (TCHAR *) malloc (*pFileCount * MAX_PATH);
+    /* second cycle: read directory and store filenames in file-list */
+    hFind = FindFirstFile(szImgFindName, &finddata);
+    bOk = (hFind != (HANDLE) -1);
+    i = 0;
+    ii = 0;
+    while (bOk)
+    {
+        strcpy (*ppFileList + ii, szImgPathName);
+        strcpy (strrchr(*ppFileList + ii, '\\') + 1, finddata.cFileName);
+        if (strcmp(pstrPathName, *ppFileList + ii) == 0)
+            *pFileIndex = i;
+        ii += MAX_PATH;
+        i++;
+        bOk = FindNextFile(hFind, &finddata);
+    }
+    FindClose(hFind);
+    /* finally we must sort the file-list */
+    for (i = 0; i < *pFileCount - 1; i++)
+    {
+        ii = i * MAX_PATH;
+        for (j = i+1; j < *pFileCount; j++)
+        {
+            jj = j * MAX_PATH;
+            if (strcmp (*ppFileList + ii, *ppFileList + jj) > 0)
+            {
+                strcpy (szTmp, *ppFileList + jj);
+                strcpy (*ppFileList + jj, *ppFileList + ii);
+                strcpy (*ppFileList + ii, szTmp);
+                /* check if this was the current image that we moved */
+                if (*pFileIndex == i)
+                    *pFileIndex = j;
+                else
+                    if (*pFileIndex == j)
+                        *pFileIndex = i;
+            }
+        }
+    }
+    return TRUE;
+}
+/*----------------
+ *  SearchPngList
+ *----------------
+ */
+BOOL SearchPngList (
+        TCHAR *pFileList, int FileCount, int *pFileIndex,
+        PTSTR pstrPrevName, PTSTR pstrNextName)
+{
+    if (FileCount > 0)
+    {
+        /* get previous entry */
+        if (pstrPrevName != NULL)
+        {
+            if (*pFileIndex > 0)
+                *pFileIndex -= 1;
+            else
+                *pFileIndex = FileCount - 1;
+            strcpy (pstrPrevName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+        /* get next entry */
+        if (pstrNextName != NULL)
+        {
+            if (*pFileIndex < FileCount - 1)
+                *pFileIndex += 1;
+            else
+                *pFileIndex = 0;
+            strcpy (pstrNextName, pFileList + (*pFileIndex * MAX_PATH));
+        }
+        return TRUE;
+    }
+    else
+    {
+        return FALSE;
+    }
+}
+/*-----------------
+ *  LoadImageFile
+ *-----------------
+ */
+BOOL LoadImageFile (HWND hwnd, PTSTR pstrPathName,
+                png_byte **ppbImage, int *pxImgSize, int *pyImgSize,
+                int *piChannels, png_color *pBkgColor)
+{
+    static TCHAR szTmp [MAX_PATH];
+    /* if there's an existing PNG, free the memory */
+    if (*ppbImage)
+    {
+        free (*ppbImage);
+        *ppbImage = NULL;
+    }
+    /* Load the entire PNG into memory */
+    SetCursor (LoadCursor (NULL, IDC_WAIT));
+    ShowCursor (TRUE);
+    PngLoadImage (pstrPathName, ppbImage, pxImgSize, pyImgSize, piChannels,
+                  pBkgColor);
+    ShowCursor (FALSE);
+    SetCursor (LoadCursor (NULL, IDC_ARROW));
+    if (*ppbImage != NULL)
+    {
+        sprintf (szTmp, "VisualPng - %s", strrchr(pstrPathName, '\\') + 1);
+        SetWindowText (hwnd, szTmp);
+    }
+    else
+    {
+        MessageBox (hwnd, TEXT ("Error in loading the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        return FALSE;
+    }
+    return TRUE;
+}
+/*----------------
+ *  DisplayImage
+ *----------------
+ */
+BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
+        BYTE **ppDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE                       *pDib = *ppDib;
+    BYTE                       *pDiData = *ppDiData;
+    /* BITMAPFILEHEADER        *pbmfh; */
+    BITMAPINFOHEADER           *pbmih;
+    WORD                        wDIRowBytes;
+    png_color                   bkgBlack = {0, 0, 0};
+    png_color                   bkgGray  = {127, 127, 127};
+    png_color                   bkgWhite = {255, 255, 255};
+    /* allocate memory for the Device Independant bitmap */
+    wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;
+    if (pDib)
+    {
+        free (pDib);
+        pDib = NULL;
+    }
+    if (!(pDib = (BYTE *) malloc (sizeof(BITMAPINFOHEADER) +
+        wDIRowBytes * cyWinSize)))
+    {
+        MessageBox (hwnd, TEXT ("Error in displaying the PNG image"),
+            szProgName, MB_ICONEXCLAMATION | MB_OK);
+        *ppDib = pDib = NULL;
+        return FALSE;
+    }
+    *ppDib = pDib;
+    memset (pDib, 0, sizeof(BITMAPINFOHEADER));
+    /* initialize the dib-structure */
+    pbmih = (BITMAPINFOHEADER *) pDib;
+    pbmih->biSize = sizeof(BITMAPINFOHEADER);
+    pbmih->biWidth = cxWinSize;
+    pbmih->biHeight = -((long) cyWinSize);
+    pbmih->biPlanes = 1;
+    pbmih->biBitCount = 24;
+    pbmih->biCompression = 0;
+    pDiData = pDib + sizeof(BITMAPINFOHEADER);
+    *ppDiData = pDiData;
+    /* first fill bitmap with gray and image border */
+    InitBitmap (pDiData, cxWinSize, cyWinSize);
+    /* then fill bitmap with image */
+    if (pbImage)
+    {
+        FillBitmap (
+            pDiData, cxWinSize, cyWinSize,
+            pbImage, cxImgSize, cyImgSize, cImgChannels,
+            bStretched);
+    }
+    return TRUE;
+}
+/*--------------
+ *  InitBitmap
+ *--------------
+ */
+BOOL InitBitmap (BYTE *pDiData, int cxWinSize, int cyWinSize)
+{
+    BYTE *dst;
+    int x, y, col;
+    /* initialize the background with gray */
+    dst = pDiData;
+    for (y = 0; y < cyWinSize; y++)
+    {
+        col = 0;
+        for (x = 0; x < cxWinSize; x++)
+        {
+            /* fill with GRAY */
+            *dst++ = 127;
+            *dst++ = 127;
+            *dst++ = 127;
+            col += 3;
+        }
+        /* rows start on 4 byte boundaries */
+        while ((col % 4) != 0)
+        {
+            dst++;
+            col++;
+        }
+    }
+    return TRUE;
+}
+/*--------------
+ *  FillBitmap
+ *--------------
+ */
+BOOL FillBitmap (
+        BYTE *pDiData, int cxWinSize, int cyWinSize,
+        BYTE *pbImage, int cxImgSize, int cyImgSize, int cImgChannels,
+        BOOL bStretched)
+{
+    BYTE *pStretchedImage;
+    BYTE *pImg;
+    BYTE *src, *dst;
+    BYTE r, g, b, a;
+    const int cDIChannels = 3;
+    WORD wImgRowBytes;
+    WORD wDIRowBytes;
+    int cxNewSize, cyNewSize;
+    int cxImgPos, cyImgPos;
+    int xImg, yImg;
+    int xWin, yWin;
+    int xOld, yOld;
+    int xNew, yNew;
+    if (bStretched)
+    {
+        cxNewSize = cxWinSize - 2 * MARGIN;
+        cyNewSize = cyWinSize - 2 * MARGIN;
+        /* stretch the image to it's window determined size */
+        /* the following two are mathematically the same, but the first
+         * has side-effects because of rounding
+         */
+/*      if ((cyNewSize / cxNewSize) > (cyImgSize / cxImgSize)) */
+        if ((cyNewSize * cxImgSize) > (cyImgSize * cxNewSize))
+        {
+            cyNewSize = cxNewSize * cyImgSize / cxImgSize;
+            cxImgPos = MARGIN;
+            cyImgPos = (cyWinSize - cyNewSize) / 2;
+        }
+        else
+        {
+            cxNewSize = cyNewSize * cxImgSize / cyImgSize;
+            cyImgPos = MARGIN;
+            cxImgPos = (cxWinSize - cxNewSize) / 2;
+        }
+        pStretchedImage = malloc (cImgChannels * cxNewSize * cyNewSize);
+        pImg = pStretchedImage;
+        for (yNew = 0; yNew < cyNewSize; yNew++)
+        {
+            yOld = yNew * cyImgSize / cyNewSize;
+            for (xNew = 0; xNew < cxNewSize; xNew++)
+            {
+                xOld = xNew * cxImgSize / cxNewSize;
+                r = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 0);
+                g = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 1);
+                b = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld) + 2);
+                *pImg++ = r;
+                *pImg++ = g;
+                *pImg++ = b;
+                if (cImgChannels == 4)
+                {
+                    a = *(pbImage + cImgChannels * ((yOld * cxImgSize) + xOld)
+                        + 3);
+                    *pImg++ = a;
+                }
+            }
+        }
+        /* calculate row-bytes */
+        wImgRowBytes = cImgChannels * cxNewSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+        /* copy image to screen */
+        for (yImg = 0, yWin = cyImgPos; yImg < cyNewSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - cyImgPos)
+                break;
+            src = pStretchedImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+            for (xImg = 0, xWin = cxImgPos; xImg < cxNewSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - cxImgPos)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+        /* free memory */
+        if (pStretchedImage != NULL)
+        {
+            free (pStretchedImage);
+            pStretchedImage = NULL;
+        }
+    }
+    /* process the image not-stretched */
+    else
+    {
+        /* calculate the central position */
+        cxImgPos = (cxWinSize - cxImgSize) / 2;
+        cyImgPos = (cyWinSize - cyImgSize) / 2;
+        /* check for image larger than window */
+        if (cxImgPos < MARGIN)
+            cxImgPos = MARGIN;
+        if (cyImgPos < MARGIN)
+            cyImgPos = MARGIN;
+        /* calculate both row-bytes */
+        wImgRowBytes = cImgChannels * cxImgSize;
+        wDIRowBytes = (WORD) ((cDIChannels * cxWinSize + 3L) >> 2) << 2;
+        /* copy image to screen */
+        for (yImg = 0, yWin = cyImgPos; yImg < cyImgSize; yImg++, yWin++)
+        {
+            if (yWin >= cyWinSize - MARGIN)
+                break;
+            src = pbImage + yImg * wImgRowBytes;
+            dst = pDiData + yWin * wDIRowBytes + cxImgPos * cDIChannels;
+            for (xImg = 0, xWin = cxImgPos; xImg < cxImgSize; xImg++, xWin++)
+            {
+                if (xWin >= cxWinSize - MARGIN)
+                    break;
+                r = *src++;
+                g = *src++;
+                b = *src++;
+                *dst++ = b; /* note the reverse order  */
+                *dst++ = g;
+                *dst++ = r;
+                if (cImgChannels == 4)
+                {
+                    a = *src++;
+                }
+            }
+        }
+    }
+    return TRUE;
+}
+/*-----------------
+ *  end of source
+ *-----------------
+ */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.ico b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.ico
new file mode 100644
index 0000000..68aa371
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.ico
Binary files differ
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.png b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.png
new file mode 100644
index 0000000..c6aa80a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.png
Binary files differ
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.rc b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.rc
new file mode 100644
index 0000000..6e0623a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/VisualPng.rc
@@ -0,0 +1,152 @@
+//Microsoft Developer Studio generated resource script.
+//
+#include "resource.h"
+#define APSTUDIO_READONLY_SYMBOLS
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 2 resource.
+//
+#include "afxres.h"
+/////////////////////////////////////////////////////////////////////////////
+#undef APSTUDIO_READONLY_SYMBOLS
+/////////////////////////////////////////////////////////////////////////////
+// English (U.S.) resources
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+#ifdef _WIN32
+LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US
+#pragma code_page(1252)
+#endif //_WIN32
+#ifdef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// TEXTINCLUDE
+//
+1 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "resource.h\0"
+END
+2 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "#include ""afxres.h""\r\n"
+    "\0"
+END
+3 TEXTINCLUDE DISCARDABLE 
+BEGIN
+    "\r\n"
+    "\0"
+END
+#endif    // APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// Menu
+//
+VISUALPNG MENU DISCARDABLE 
+BEGIN
+    POPUP "&File"
+    BEGIN
+        MENUITEM "&Open Image...\tCtrl+O",      IDM_FILE_OPEN
+        MENUITEM "Save &As...",                 IDM_FILE_SAVE
+        MENUITEM SEPARATOR
+        MENUITEM "&Next Image\tCtrl+N",         IDM_FILE_NEXT
+        MENUITEM "Pre&vious Image\tCtrl+V",     IDM_FILE_PREVIOUS
+        MENUITEM SEPARATOR
+        MENUITEM "E&xit\tAlt+X",                IDM_FILE_EXIT
+    END
+    POPUP "&Options"
+    BEGIN
+        MENUITEM "&Stretch",                    IDM_OPTIONS_STRETCH, CHECKED
+    END
+    POPUP "&Help"
+    BEGIN
+        MENUITEM "&About",                      IDM_HELP_ABOUT
+    END
+END
+/////////////////////////////////////////////////////////////////////////////
+//
+// Accelerator
+//
+VISUALPNG ACCELERATORS DISCARDABLE 
+BEGIN
+    "N",            IDM_FILE_NEXT,          VIRTKEY, CONTROL, NOINVERT
+    "O",            IDM_FILE_OPEN,          VIRTKEY, CONTROL, NOINVERT
+    "P",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "V",            IDM_FILE_PREVIOUS,      VIRTKEY, CONTROL, NOINVERT
+    "X",            IDM_FILE_EXIT,          VIRTKEY, ALT, NOINVERT
+END
+/////////////////////////////////////////////////////////////////////////////
+//
+// Icon
+//
+// Icon with lowest ID value placed first to ensure application icon
+// remains consistent on all systems.
+VISUALPNG               ICON    DISCARDABLE     "VisualPng.ico"
+/////////////////////////////////////////////////////////////////////////////
+//
+// Dialog
+//
+ABOUTBOX DIALOG DISCARDABLE  0, 0, 186, 94
+STYLE DS_MODALFRAME | WS_POPUP
+FONT 8, "MS Sans Serif"
+BEGIN
+    DEFPUSHBUTTON   "OK",IDOK,68,67,50,14
+    CTEXT           "VisualPng 1.0  -  June 2000",IDC_STATIC,49,14,88,8
+    LTEXT           "a PNG image viewer",IDC_STATIC,60,30,66,8
+    LTEXT           "(c) Willem van Schaik, 2000",IDC_STATIC,48,52,90,8
+    LTEXT           "to demonstrate the use of libpng in Visual C",
+                    IDC_STATIC,25,38,136,8
+END
+/////////////////////////////////////////////////////////////////////////////
+//
+// DESIGNINFO
+//
+#ifdef APSTUDIO_INVOKED
+GUIDELINES DESIGNINFO DISCARDABLE 
+BEGIN
+    "ABOUTBOX", DIALOG
+    BEGIN
+        LEFTMARGIN, 7
+        RIGHTMARGIN, 179
+        TOPMARGIN, 7
+        BOTTOMMARGIN, 87
+    END
+END
+#endif    // APSTUDIO_INVOKED
+#endif    // English (U.S.) resources
+/////////////////////////////////////////////////////////////////////////////
+#ifndef APSTUDIO_INVOKED
+/////////////////////////////////////////////////////////////////////////////
+//
+// Generated from the TEXTINCLUDE 3 resource.
+//
+/////////////////////////////////////////////////////////////////////////////
+#endif    // not APSTUDIO_INVOKED
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/cexcept.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/cexcept.h
new file mode 100644
index 0000000..83c8bfe
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/cexcept.h
@@ -0,0 +1,248 @@
+/*===
+cexcept.h 2.0.1 (2008-Jul-19-Sat)
+http://www.nicemice.net/cexcept/
+Adam M. Costello
+http://www.nicemice.net/amc/
+An interface for exception-handling in ANSI C (C89 and subsequent ISO
+standards), developed jointly with Cosmin Truta.
+    Copyright (c) 2000-2008 Adam M. Costello and Cosmin Truta.
+    This software may be modified only if its author and version
+    information is updated accurately, and may be redistributed
+    only if accompanied by this unaltered notice.  Subject to those
+    restrictions, permission is granted to anyone to do anything
+    with this software.  The copyright holders make no guarantees
+    regarding this software, and are not responsible for any damage
+    resulting from its use.
+The cexcept interface is not compatible with and cannot interact
+with system exceptions (like division by zero or memory segmentation
+violation), compiler-generated exceptions (like C++ exceptions), or
+other exception-handling interfaces.
+When using this interface across multiple .c files, do not include
+this header file directly.  Instead, create a wrapper header file that
+includes this header file and then invokes the define_exception_type
+macro (see below).  The .c files should then include that header file.
+The interface consists of one type, one well-known name, and six macros.
+define_exception_type(type_name);
+    This macro is used like an external declaration.  It specifies
+    the type of object that gets copied from the exception thrower to
+    the exception catcher.  The type_name can be any type that can be
+    assigned to, that is, a non-constant arithmetic type, struct, union,
+    or pointer.  Examples:
+        define_exception_type(int);
+        enum exception { out_of_memory, bad_arguments, disk_full };
+        define_exception_type(enum exception);
+        struct exception { int code; const char *msg; };
+        define_exception_type(struct exception);
+    Because throwing an exception causes the object to be copied (not
+    just once, but twice), programmers may wish to consider size when
+    choosing the exception type.
+struct exception_context;
+    This type may be used after the define_exception_type() macro has
+    been invoked.  A struct exception_context must be known to both
+    the thrower and the catcher.  It is expected that there be one
+    context for each thread that uses exceptions.  It would certainly
+    be dangerous for multiple threads to access the same context.
+    One thread can use multiple contexts, but that is likely to be
+    confusing and not typically useful.  The application can allocate
+    this structure in any way it pleases--automatic, static, or dynamic.
+    The application programmer should pretend not to know the structure
+    members, which are subject to change.
+struct exception_context *the_exception_context;
+    The Try/Catch and Throw statements (described below) implicitly
+    refer to a context, using the name the_exception_context.  It is
+    the application's responsibility to make sure that this name yields
+    the address of a mutable (non-constant) struct exception_context
+    wherever those statements are used.  Subject to that constraint, the
+    application may declare a variable of this name anywhere it likes
+    (inside a function, in a parameter list, or externally), and may
+    use whatever storage class specifiers (static, extern, etc) or type
+    qualifiers (const, volatile, etc) it likes.  Examples:
+        static struct exception_context
+          * const the_exception_context = &foo;
+        { struct exception_context *the_exception_context = bar; ... }
+        int blah(struct exception_context *the_exception_context, ...);
+        extern struct exception_context the_exception_context[1];
+    The last example illustrates a trick that avoids creating a pointer
+    object separate from the structure object.
+    The name could even be a macro, for example:
+        struct exception_context ec_array[numthreads];
+        #define the_exception_context (ec_array + thread_id)
+    Be aware that the_exception_context is used several times by the
+    Try/Catch/Throw macros, so it shouldn't be expensive or have side
+    effects.  The expansion must be a drop-in replacement for an
+    identifier, so it's safest to put parentheses around it.
+void init_exception_context(struct exception_context *ec);
+    For context structures allocated statically (by an external
+    definition or using the "static" keyword), the implicit
+    initialization to all zeros is sufficient, but contexts allocated
+    by other means must be initialized using this macro before they
+    are used by a Try/Catch statement.  It does no harm to initialize
+    a context more than once (by using this macro on a statically
+    allocated context, or using this macro twice on the same context),
+    but a context must not be re-initialized after it has been used by a
+    Try/Catch statement.
+Try statement
+Catch (expression) statement
+    The Try/Catch/Throw macros are capitalized in order to avoid
+    confusion with the C++ keywords, which have subtly different
+    semantics.
+    A Try/Catch statement has a syntax similar to an if/else statement,
+    except that the parenthesized expression goes after the second
+    keyword rather than the first.  As with if/else, there are two
+    clauses, each of which may be a simple statement ending with a
+    semicolon or a brace-enclosed compound statement.  But whereas
+    the else clause is optional, the Catch clause is required.  The
+    expression must be a modifiable lvalue (something capable of being
+    assigned to) of the same type (disregarding type qualifiers) that
+    was passed to define_exception_type().
+    If a Throw that uses the same exception context as the Try/Catch is
+    executed within the Try clause (typically within a function called
+    by the Try clause), and the exception is not caught by a nested
+    Try/Catch statement, then a copy of the exception will be assigned
+    to the expression, and control will jump to the Catch clause.  If no
+    such Throw is executed, then the assignment is not performed, and
+    the Catch clause is not executed.
+    The expression is not evaluated unless and until the exception is
+    caught, which is significant if it has side effects, for example:
+        Try foo();
+        Catch (p[++i].e) { ... }
+    IMPORTANT: Jumping into or out of a Try clause (for example via
+    return, break, continue, goto, longjmp) is forbidden--the compiler
+    will not complain, but bad things will happen at run-time.  Jumping
+    into or out of a Catch clause is okay, and so is jumping around
+    inside a Try clause.  In many cases where one is tempted to return
+    from a Try clause, it will suffice to use Throw, and then return
+    from the Catch clause.  Another option is to set a flag variable and
+    use goto to jump to the end of the Try clause, then check the flag
+    after the Try/Catch statement.
+    IMPORTANT: The values of any non-volatile automatic variables
+    changed within the Try clause are undefined after an exception is
+    caught.  Therefore, variables modified inside the Try block whose
+    values are needed later outside the Try block must either use static
+    storage or be declared with the "volatile" type qualifier.
+Throw expression;
+    A Throw statement is very much like a return statement, except that
+    the expression is required.  Whereas return jumps back to the place
+    where the current function was called, Throw jumps back to the Catch
+    clause of the innermost enclosing Try clause.  The expression must
+    be compatible with the type passed to define_exception_type().  The
+    exception must be caught, otherwise the program may crash.
+    Slight limitation:  If the expression is a comma-expression, it must
+    be enclosed in parentheses.
+Try statement
+Catch_anonymous statement
+    When the value of the exception is not needed, a Try/Catch statement
+    can use Catch_anonymous instead of Catch (expression).
+Everything below this point is for the benefit of the compiler.  The
+application programmer should pretend not to know any of it, because it
+is subject to change.
+===*/
+#ifndef CEXCEPT_H
+#define CEXCEPT_H
+#include <setjmp.h>
+#define define_exception_type(etype) \
+struct exception_context { \
+  jmp_buf *penv; \
+  int caught; \
+  volatile struct { etype etmp; } v; \
+}
+/* etmp must be volatile because the application might use automatic */
+/* storage for the_exception_context, and etmp is modified between   */
+/* the calls to setjmp() and longjmp().  A wrapper struct is used to */
+/* avoid warnings about a duplicate volatile qualifier in case etype */
+/* already includes it.                                              */
+#define init_exception_context(ec) ((void)((ec)->penv = 0))
+#define Try \
+  { \
+    jmp_buf *exception__prev, exception__env; \
+    exception__prev = the_exception_context->penv; \
+    the_exception_context->penv = &exception__env; \
+    if (setjmp(exception__env) == 0) { \
+      do
+#define exception__catch(action) \
+      while (the_exception_context->caught = 0, \
+             the_exception_context->caught); \
+    } \
+    else { \
+      the_exception_context->caught = 1; \
+    } \
+    the_exception_context->penv = exception__prev; \
+  } \
+  if (!the_exception_context->caught || action) { } \
+  else
+#define Catch(e) exception__catch(((e) = the_exception_context->v.etmp, 0))
+#define Catch_anonymous exception__catch(0)
+/* Try ends with do, and Catch begins with while(0) and ends with     */
+/* else, to ensure that Try/Catch syntax is similar to if/else        */
+/* syntax.                                                            */
+/*                                                                    */
+/* The 0 in while(0) is expressed as x=0,x in order to appease        */
+/* compilers that warn about constant expressions inside while().     */
+/* Most compilers should still recognize that the condition is always */
+/* false and avoid generating code for it.                            */
+#define Throw \
+  for (;; longjmp(*the_exception_context->penv, 1)) \
+    the_exception_context->v.etmp =
+#endif /* CEXCEPT_H */
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/resource.h b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/resource.h
new file mode 100644
index 0000000..a06050a
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib/visupng/resource.h
@@ -0,0 +1,23 @@
+//{{NO_DEPENDENCIES}}
+// Microsoft Developer Studio generated include file.
+// Used by VisualPng.rc
+//
+#define IDM_FILE_OPEN                   40001
+#define IDM_FILE_SAVE                   40002
+#define IDM_FILE_NEXT                   40003
+#define IDM_FILE_PREVIOUS               40004
+#define IDM_FILE_EXIT                   40005
+#define IDM_OPTIONS_BACKGROUND          40006
+#define IDM_OPTIONS_STRETCH             40007
+#define IDM_HELP_ABOUT                  40008
+// Next default values for new objects
+//
+#ifdef APSTUDIO_INVOKED
+#ifndef APSTUDIO_READONLY_SYMBOLS
+#define _APS_NEXT_RESOURCE_VALUE        113
+#define _APS_NEXT_COMMAND_VALUE         40009
+#define _APS_NEXT_CONTROL_VALUE         1001
+#define _APS_NEXT_SYMED_VALUE           101
+#endif
+#endif
author	David Walter Seikel	2013-01-13 17:24:39 +1000
committer	David Walter Seikel	2013-01-13 17:24:39 +1000
commit	393b5cd1dc438872af89d334ef6e5fcc59f27d47 (patch)
tree	6a14521219942a08a1b95cb2f5a923a9edd60f63 /libraries/irrlicht-1.8/source/Irrlicht/libpng/contrib
parent	Add a note about rasters suggested start up code. (diff)
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