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/jpeglib/jccolor.c
parent: Add a note about rasters suggested start up code. (diff)
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diff --git a/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c
new file mode 100644
index 0000000..12d35f4
--- /dev/null
+++ b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c
@@ -0,0 +1,490 @@
+/*
+ * jccolor.c
+ *
+ * Copyright (C) 1991-1996, Thomas G. Lane.
+ * Modified 2011 by Guido Vollbeding.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README file.
+ *
+ * This file contains input colorspace conversion routines.
+ */
+#define JPEG_INTERNALS
+#include "jinclude.h"
+#include "jpeglib.h"
+/* Private subobject */
+typedef struct {
+  struct jpeg_color_converter pub; /* public fields */
+  /* Private state for RGB->YCC conversion */
+  INT32 * rgb_ycc_tab;          /* => table for RGB to YCbCr conversion */
+} my_color_converter;
+typedef my_color_converter * my_cconvert_ptr;
+/**************** RGB -> YCbCr conversion: most common case **************/
+/*
+ * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
+ * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
+ * The conversion equations to be implemented are therefore
+ *      Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
+ *      Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
+ *      Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
+ * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
+ * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
+ * rather than CENTERJSAMPLE, for Cb and Cr.  This gave equal positive and
+ * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
+ * were not represented exactly.  Now we sacrifice exact representation of
+ * maximum red and maximum blue in order to get exact grayscales.
+ *
+ * To avoid floating-point arithmetic, we represent the fractional constants
+ * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
+ * the products by 2^16, with appropriate rounding, to get the correct answer.
+ *
+ * For even more speed, we avoid doing any multiplications in the inner loop
+ * by precalculating the constants times R,G,B for all possible values.
+ * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
+ * for 12-bit samples it is still acceptable.  It's not very reasonable for
+ * 16-bit samples, but if you want lossless storage you shouldn't be changing
+ * colorspace anyway.
+ * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
+ * in the tables to save adding them separately in the inner loop.
+ */
+#define SCALEBITS       16      /* speediest right-shift on some machines */
+#define CBCR_OFFSET     ((INT32) CENTERJSAMPLE << SCALEBITS)
+#define ONE_HALF        ((INT32) 1 << (SCALEBITS-1))
+#define FIX(x)          ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
+/* We allocate one big table and divide it up into eight parts, instead of
+ * doing eight alloc_small requests.  This lets us use a single table base
+ * address, which can be held in a register in the inner loops on many
+ * machines (more than can hold all eight addresses, anyway).
+ */
+#define R_Y_OFF         0                       /* offset to R => Y section */
+#define G_Y_OFF         (1*(MAXJSAMPLE+1))      /* offset to G => Y section */
+#define B_Y_OFF         (2*(MAXJSAMPLE+1))      /* etc. */
+#define R_CB_OFF        (3*(MAXJSAMPLE+1))
+#define G_CB_OFF        (4*(MAXJSAMPLE+1))
+#define B_CB_OFF        (5*(MAXJSAMPLE+1))
+#define R_CR_OFF        B_CB_OFF                /* B=>Cb, R=>Cr are the same */
+#define G_CR_OFF        (6*(MAXJSAMPLE+1))
+#define B_CR_OFF        (7*(MAXJSAMPLE+1))
+#define TABLE_SIZE      (8*(MAXJSAMPLE+1))
+/*
+ * Initialize for RGB->YCC colorspace conversion.
+ */
+METHODDEF(void)
+rgb_ycc_start (j_compress_ptr cinfo)
+{
+  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+  INT32 * rgb_ycc_tab;
+  INT32 i;
+  /* Allocate and fill in the conversion tables. */
+  cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
+    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                (TABLE_SIZE * SIZEOF(INT32)));
+  for (i = 0; i <= MAXJSAMPLE; i++) {
+    rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
+    rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
+    rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i     + ONE_HALF;
+    rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
+    rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
+    /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
+     * This ensures that the maximum output will round to MAXJSAMPLE
+     * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
+     */
+    rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
+/*  B=>Cb and R=>Cr tables are the same
+    rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
+*/
+    rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
+    rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
+  }
+}
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ *
+ * Note that we change from the application's interleaved-pixel format
+ * to our internal noninterleaved, one-plane-per-component format.
+ * The input buffer is therefore three times as wide as the output buffer.
+ *
+ * A starting row offset is provided only for the output buffer.  The caller
+ * can easily adjust the passed input_buf value to accommodate any row
+ * offset required on that side.
+ */
+METHODDEF(void)
+rgb_ycc_convert (j_compress_ptr cinfo,
+                 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                 JDIMENSION output_row, int num_rows)
+{
+  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+  register int r, g, b;
+  register INT32 * ctab = cconvert->rgb_ycc_tab;
+  register JSAMPROW inptr;
+  register JSAMPROW outptr0, outptr1, outptr2;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr0 = output_buf[0][output_row];
+    outptr1 = output_buf[1][output_row];
+    outptr2 = output_buf[2][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      r = GETJSAMPLE(inptr[RGB_RED]);
+      g = GETJSAMPLE(inptr[RGB_GREEN]);
+      b = GETJSAMPLE(inptr[RGB_BLUE]);
+      inptr += RGB_PIXELSIZE;
+      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
+       * must be too; we do not need an explicit range-limiting operation.
+       * Hence the value being shifted is never negative, and we don't
+       * need the general RIGHT_SHIFT macro.
+       */
+      /* Y */
+      outptr0[col] = (JSAMPLE)
+                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+                 >> SCALEBITS);
+      /* Cb */
+      outptr1[col] = (JSAMPLE)
+                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+                 >> SCALEBITS);
+      /* Cr */
+      outptr2[col] = (JSAMPLE)
+                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+                 >> SCALEBITS);
+    }
+  }
+}
+/**************** Cases other than RGB -> YCbCr **************/
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles RGB->grayscale conversion, which is the same
+ * as the RGB->Y portion of RGB->YCbCr.
+ * We assume rgb_ycc_start has been called (we only use the Y tables).
+ */
+METHODDEF(void)
+rgb_gray_convert (j_compress_ptr cinfo,
+                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                  JDIMENSION output_row, int num_rows)
+{
+  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+  register int r, g, b;
+  register INT32 * ctab = cconvert->rgb_ycc_tab;
+  register JSAMPROW inptr;
+  register JSAMPROW outptr;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr = output_buf[0][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      r = GETJSAMPLE(inptr[RGB_RED]);
+      g = GETJSAMPLE(inptr[RGB_GREEN]);
+      b = GETJSAMPLE(inptr[RGB_BLUE]);
+      inptr += RGB_PIXELSIZE;
+      /* Y */
+      outptr[col] = (JSAMPLE)
+                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+                 >> SCALEBITS);
+    }
+  }
+}
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles Adobe-style CMYK->YCCK conversion,
+ * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
+ * conversion as above, while passing K (black) unchanged.
+ * We assume rgb_ycc_start has been called.
+ */
+METHODDEF(void)
+cmyk_ycck_convert (j_compress_ptr cinfo,
+                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                   JDIMENSION output_row, int num_rows)
+{
+  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
+  register int r, g, b;
+  register INT32 * ctab = cconvert->rgb_ycc_tab;
+  register JSAMPROW inptr;
+  register JSAMPROW outptr0, outptr1, outptr2, outptr3;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr0 = output_buf[0][output_row];
+    outptr1 = output_buf[1][output_row];
+    outptr2 = output_buf[2][output_row];
+    outptr3 = output_buf[3][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
+      g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
+      b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
+      /* K passes through as-is */
+      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
+      inptr += 4;
+      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
+       * must be too; we do not need an explicit range-limiting operation.
+       * Hence the value being shifted is never negative, and we don't
+       * need the general RIGHT_SHIFT macro.
+       */
+      /* Y */
+      outptr0[col] = (JSAMPLE)
+                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
+                 >> SCALEBITS);
+      /* Cb */
+      outptr1[col] = (JSAMPLE)
+                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
+                 >> SCALEBITS);
+      /* Cr */
+      outptr2[col] = (JSAMPLE)
+                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
+                 >> SCALEBITS);
+    }
+  }
+}
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles grayscale output with no conversion.
+ * The source can be either plain grayscale or YCbCr (since Y == gray).
+ */
+METHODDEF(void)
+grayscale_convert (j_compress_ptr cinfo,
+                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+                   JDIMENSION output_row, int num_rows)
+{
+  register JSAMPROW inptr;
+  register JSAMPROW outptr;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+  int instride = cinfo->input_components;
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr = output_buf[0][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      outptr[col] = inptr[0];   /* don't need GETJSAMPLE() here */
+      inptr += instride;
+    }
+  }
+}
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * No colorspace conversion, but change from interleaved
+ * to separate-planes representation.
+ */
+METHODDEF(void)
+rgb_convert (j_compress_ptr cinfo,
+             JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+             JDIMENSION output_row, int num_rows)
+{
+  register JSAMPROW inptr;
+  register JSAMPROW outptr0, outptr1, outptr2;
+  register JDIMENSION col;
+  JDIMENSION num_cols = cinfo->image_width;
+  while (--num_rows >= 0) {
+    inptr = *input_buf++;
+    outptr0 = output_buf[0][output_row];
+    outptr1 = output_buf[1][output_row];
+    outptr2 = output_buf[2][output_row];
+    output_row++;
+    for (col = 0; col < num_cols; col++) {
+      /* We can dispense with GETJSAMPLE() here */
+      outptr0[col] = inptr[RGB_RED];
+      outptr1[col] = inptr[RGB_GREEN];
+      outptr2[col] = inptr[RGB_BLUE];
+      inptr += RGB_PIXELSIZE;
+    }
+  }
+}
+/*
+ * Convert some rows of samples to the JPEG colorspace.
+ * This version handles multi-component colorspaces without conversion.
+ * We assume input_components == num_components.
+ */
+METHODDEF(void)
+null_convert (j_compress_ptr cinfo,
+              JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
+              JDIMENSION output_row, int num_rows)
+{
+  register JSAMPROW inptr;
+  register JSAMPROW outptr;
+  register JDIMENSION col;
+  register int ci;
+  int nc = cinfo->num_components;
+  JDIMENSION num_cols = cinfo->image_width;
+  while (--num_rows >= 0) {
+    /* It seems fastest to make a separate pass for each component. */
+    for (ci = 0; ci < nc; ci++) {
+      inptr = *input_buf;
+      outptr = output_buf[ci][output_row];
+      for (col = 0; col < num_cols; col++) {
+        outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
+        inptr += nc;
+      }
+    }
+    input_buf++;
+    output_row++;
+  }
+}
+/*
+ * Empty method for start_pass.
+ */
+METHODDEF(void)
+null_method (j_compress_ptr cinfo)
+{
+  /* no work needed */
+}
+/*
+ * Module initialization routine for input colorspace conversion.
+ */
+GLOBAL(void)
+jinit_color_converter (j_compress_ptr cinfo)
+{
+  my_cconvert_ptr cconvert;
+  cconvert = (my_cconvert_ptr)
+    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+                                SIZEOF(my_color_converter));
+  cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
+  /* set start_pass to null method until we find out differently */
+  cconvert->pub.start_pass = null_method;
+  /* Make sure input_components agrees with in_color_space */
+  switch (cinfo->in_color_space) {
+  case JCS_GRAYSCALE:
+    if (cinfo->input_components != 1)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
+  case JCS_RGB:
+    if (cinfo->input_components != RGB_PIXELSIZE)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
+  case JCS_YCbCr:
+    if (cinfo->input_components != 3)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
+  case JCS_CMYK:
+  case JCS_YCCK:
+    if (cinfo->input_components != 4)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
+  default:                      /* JCS_UNKNOWN can be anything */
+    if (cinfo->input_components < 1)
+      ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
+    break;
+  }
+  /* Check num_components, set conversion method based on requested space */
+  switch (cinfo->jpeg_color_space) {
+  case JCS_GRAYSCALE:
+    if (cinfo->num_components != 1)
+      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+    if (cinfo->in_color_space == JCS_GRAYSCALE ||
+        cinfo->in_color_space == JCS_YCbCr)
+      cconvert->pub.color_convert = grayscale_convert;
+    else if (cinfo->in_color_space == JCS_RGB) {
+      cconvert->pub.start_pass = rgb_ycc_start;
+      cconvert->pub.color_convert = rgb_gray_convert;
+    } else
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    break;
+  case JCS_RGB:
+    if (cinfo->num_components != 3)
+      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+    if (cinfo->in_color_space == JCS_RGB)
+      cconvert->pub.color_convert = rgb_convert;
+    else
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    break;
+  case JCS_YCbCr:
+    if (cinfo->num_components != 3)
+      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+    if (cinfo->in_color_space == JCS_RGB) {
+      cconvert->pub.start_pass = rgb_ycc_start;
+      cconvert->pub.color_convert = rgb_ycc_convert;
+    } else if (cinfo->in_color_space == JCS_YCbCr)
+      cconvert->pub.color_convert = null_convert;
+    else
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    break;
+  case JCS_CMYK:
+    if (cinfo->num_components != 4)
+      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+    if (cinfo->in_color_space == JCS_CMYK)
+      cconvert->pub.color_convert = null_convert;
+    else
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    break;
+  case JCS_YCCK:
+    if (cinfo->num_components != 4)
+      ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
+    if (cinfo->in_color_space == JCS_CMYK) {
+      cconvert->pub.start_pass = rgb_ycc_start;
+      cconvert->pub.color_convert = cmyk_ycck_convert;
+    } else if (cinfo->in_color_space == JCS_YCCK)
+      cconvert->pub.color_convert = null_convert;
+    else
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    break;
+  default:                      /* allow null conversion of JCS_UNKNOWN */
+    if (cinfo->jpeg_color_space != cinfo->in_color_space ||
+        cinfo->num_components != cinfo->input_components)
+      ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
+    cconvert->pub.color_convert = null_convert;
+    break;
+  }
+}
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/jpeglib/jccolor.c
parent	Add a note about rasters suggested start up code. (diff)
download	SledjHamr-393b5cd1dc438872af89d334ef6e5fcc59f27d47.zip SledjHamr-393b5cd1dc438872af89d334ef6e5fcc59f27d47.tar.gz SledjHamr-393b5cd1dc438872af89d334ef6e5fcc59f27d47.tar.bz2 SledjHamr-393b5cd1dc438872af89d334ef6e5fcc59f27d47.tar.xz

diff --git a/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c new file mode 100644 index 0000000..12d35f4 --- /dev/null +++ b/libraries/irrlicht-1.8/source/Irrlicht/jpeglib/jccolor.c
@@ -0,0 +1,490 @@
	1	/*
	2	* jccolor.c
	3	*
	4	* Copyright (C) 1991-1996, Thomas G. Lane.
	5	* Modified 2011 by Guido Vollbeding.
	6	* This file is part of the Independent JPEG Group's software.
	7	* For conditions of distribution and use, see the accompanying README file.
	8	*
	9	* This file contains input colorspace conversion routines.
	10	*/
	11
	12	#define JPEG_INTERNALS
	13	#include "jinclude.h"
	14	#include "jpeglib.h"
	15
	16
	17	/* Private subobject */
	18
	19	typedef struct {
	20	struct jpeg_color_converter pub; /* public fields */
	21
	22	/* Private state for RGB->YCC conversion */
	23	INT32 * rgb_ycc_tab; /* => table for RGB to YCbCr conversion */
	24	} my_color_converter;
	25
	26	typedef my_color_converter * my_cconvert_ptr;
	27
	28
	29	/************** RGB -> YCbCr conversion: most common case ************/
	30
	31	/*
	32	* YCbCr is defined per CCIR 601-1, except that Cb and Cr are
	33	* normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
	34	* The conversion equations to be implemented are therefore
	35	* Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
	36	* Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE
	37	* Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE
	38	* (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
	39	* Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
	40	* rather than CENTERJSAMPLE, for Cb and Cr. This gave equal positive and
	41	* negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
	42	* were not represented exactly. Now we sacrifice exact representation of
	43	* maximum red and maximum blue in order to get exact grayscales.
	44	*
	45	* To avoid floating-point arithmetic, we represent the fractional constants
	46	* as integers scaled up by 2^16 (about 4 digits precision); we have to divide
	47	* the products by 2^16, with appropriate rounding, to get the correct answer.
	48	*
	49	* For even more speed, we avoid doing any multiplications in the inner loop
	50	* by precalculating the constants times R,G,B for all possible values.
	51	* For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
	52	* for 12-bit samples it is still acceptable. It's not very reasonable for
	53	* 16-bit samples, but if you want lossless storage you shouldn't be changing
	54	* colorspace anyway.
	55	* The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
	56	* in the tables to save adding them separately in the inner loop.
	57	*/
	58
	59	#define SCALEBITS 16 /* speediest right-shift on some machines */
	60	#define CBCR_OFFSET ((INT32) CENTERJSAMPLE << SCALEBITS)
	61	#define ONE_HALF ((INT32) 1 << (SCALEBITS-1))
	62	#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
	63
	64	/* We allocate one big table and divide it up into eight parts, instead of
	65	* doing eight alloc_small requests. This lets us use a single table base
	66	* address, which can be held in a register in the inner loops on many
	67	* machines (more than can hold all eight addresses, anyway).
	68	*/
	69
	70	#define R_Y_OFF 0 /* offset to R => Y section */
	71	#define G_Y_OFF (1(MAXJSAMPLE+1)) / offset to G => Y section */
	72	#define B_Y_OFF (2(MAXJSAMPLE+1)) / etc. */
	73	#define R_CB_OFF (3*(MAXJSAMPLE+1))
	74	#define G_CB_OFF (4*(MAXJSAMPLE+1))
	75	#define B_CB_OFF (5*(MAXJSAMPLE+1))
	76	#define R_CR_OFF B_CB_OFF /* B=>Cb, R=>Cr are the same */
	77	#define G_CR_OFF (6*(MAXJSAMPLE+1))
	78	#define B_CR_OFF (7*(MAXJSAMPLE+1))
	79	#define TABLE_SIZE (8*(MAXJSAMPLE+1))
	80
	81
	82	/*
	83	* Initialize for RGB->YCC colorspace conversion.
	84	*/
	85
	86	METHODDEF(void)
	87	rgb_ycc_start (j_compress_ptr cinfo)
	88	{
	89	my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
	90	INT32 * rgb_ycc_tab;
	91	INT32 i;
	92
	93	/* Allocate and fill in the conversion tables. */
	94	cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
	95	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
	96	(TABLE_SIZE * SIZEOF(INT32)));
	97
	98	for (i = 0; i <= MAXJSAMPLE; i++) {
	99	rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
	100	rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
	101	rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i + ONE_HALF;
	102	rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
	103	rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
	104	/* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
	105	* This ensures that the maximum output will round to MAXJSAMPLE
	106	* not MAXJSAMPLE+1, and thus that we don't have to range-limit.
	107	*/
	108	rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
	109	/* B=>Cb and R=>Cr tables are the same
	110	rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1;
	111	*/
	112	rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
	113	rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
	114	}
	115	}
	116
	117
	118	/*
	119	* Convert some rows of samples to the JPEG colorspace.
	120	*
	121	* Note that we change from the application's interleaved-pixel format
	122	* to our internal noninterleaved, one-plane-per-component format.
	123	* The input buffer is therefore three times as wide as the output buffer.
	124	*
	125	* A starting row offset is provided only for the output buffer. The caller
	126	* can easily adjust the passed input_buf value to accommodate any row
	127	* offset required on that side.
	128	*/
	129
	130	METHODDEF(void)
	131	rgb_ycc_convert (j_compress_ptr cinfo,
	132	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	133	JDIMENSION output_row, int num_rows)
	134	{
	135	my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
	136	register int r, g, b;
	137	register INT32 * ctab = cconvert->rgb_ycc_tab;
	138	register JSAMPROW inptr;
	139	register JSAMPROW outptr0, outptr1, outptr2;
	140	register JDIMENSION col;
	141	JDIMENSION num_cols = cinfo->image_width;
	142
	143	while (--num_rows >= 0) {
	144	inptr = *input_buf++;
	145	outptr0 = output_buf[0][output_row];
	146	outptr1 = output_buf[1][output_row];
	147	outptr2 = output_buf[2][output_row];
	148	output_row++;
	149	for (col = 0; col < num_cols; col++) {
	150	r = GETJSAMPLE(inptr[RGB_RED]);
	151	g = GETJSAMPLE(inptr[RGB_GREEN]);
	152	b = GETJSAMPLE(inptr[RGB_BLUE]);
	153	inptr += RGB_PIXELSIZE;
	154	/* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
	155	* must be too; we do not need an explicit range-limiting operation.
	156	* Hence the value being shifted is never negative, and we don't
	157	* need the general RIGHT_SHIFT macro.
	158	*/
	159	/* Y */
	160	outptr0[col] = (JSAMPLE)
	161	((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
	162	>> SCALEBITS);
	163	/* Cb */
	164	outptr1[col] = (JSAMPLE)
	165	((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
	166	>> SCALEBITS);
	167	/* Cr */
	168	outptr2[col] = (JSAMPLE)
	169	((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
	170	>> SCALEBITS);
	171	}
	172	}
	173	}
	174
	175
	176	/************** Cases other than RGB -> YCbCr ************/
	177
	178
	179	/*
	180	* Convert some rows of samples to the JPEG colorspace.
	181	* This version handles RGB->grayscale conversion, which is the same
	182	* as the RGB->Y portion of RGB->YCbCr.
	183	* We assume rgb_ycc_start has been called (we only use the Y tables).
	184	*/
	185
	186	METHODDEF(void)
	187	rgb_gray_convert (j_compress_ptr cinfo,
	188	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	189	JDIMENSION output_row, int num_rows)
	190	{
	191	my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
	192	register int r, g, b;
	193	register INT32 * ctab = cconvert->rgb_ycc_tab;
	194	register JSAMPROW inptr;
	195	register JSAMPROW outptr;
	196	register JDIMENSION col;
	197	JDIMENSION num_cols = cinfo->image_width;
	198
	199	while (--num_rows >= 0) {
	200	inptr = *input_buf++;
	201	outptr = output_buf[0][output_row];
	202	output_row++;
	203	for (col = 0; col < num_cols; col++) {
	204	r = GETJSAMPLE(inptr[RGB_RED]);
	205	g = GETJSAMPLE(inptr[RGB_GREEN]);
	206	b = GETJSAMPLE(inptr[RGB_BLUE]);
	207	inptr += RGB_PIXELSIZE;
	208	/* Y */
	209	outptr[col] = (JSAMPLE)
	210	((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
	211	>> SCALEBITS);
	212	}
	213	}
	214	}
	215
	216
	217	/*
	218	* Convert some rows of samples to the JPEG colorspace.
	219	* This version handles Adobe-style CMYK->YCCK conversion,
	220	* where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
	221	* conversion as above, while passing K (black) unchanged.
	222	* We assume rgb_ycc_start has been called.
	223	*/
	224
	225	METHODDEF(void)
	226	cmyk_ycck_convert (j_compress_ptr cinfo,
	227	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	228	JDIMENSION output_row, int num_rows)
	229	{
	230	my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
	231	register int r, g, b;
	232	register INT32 * ctab = cconvert->rgb_ycc_tab;
	233	register JSAMPROW inptr;
	234	register JSAMPROW outptr0, outptr1, outptr2, outptr3;
	235	register JDIMENSION col;
	236	JDIMENSION num_cols = cinfo->image_width;
	237
	238	while (--num_rows >= 0) {
	239	inptr = *input_buf++;
	240	outptr0 = output_buf[0][output_row];
	241	outptr1 = output_buf[1][output_row];
	242	outptr2 = output_buf[2][output_row];
	243	outptr3 = output_buf[3][output_row];
	244	output_row++;
	245	for (col = 0; col < num_cols; col++) {
	246	r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
	247	g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
	248	b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
	249	/* K passes through as-is */
	250	outptr3[col] = inptr[3]; /* don't need GETJSAMPLE here */
	251	inptr += 4;
	252	/* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
	253	* must be too; we do not need an explicit range-limiting operation.
	254	* Hence the value being shifted is never negative, and we don't
	255	* need the general RIGHT_SHIFT macro.
	256	*/
	257	/* Y */
	258	outptr0[col] = (JSAMPLE)
	259	((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
	260	>> SCALEBITS);
	261	/* Cb */
	262	outptr1[col] = (JSAMPLE)
	263	((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
	264	>> SCALEBITS);
	265	/* Cr */
	266	outptr2[col] = (JSAMPLE)
	267	((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
	268	>> SCALEBITS);
	269	}
	270	}
	271	}
	272
	273
	274	/*
	275	* Convert some rows of samples to the JPEG colorspace.
	276	* This version handles grayscale output with no conversion.
	277	* The source can be either plain grayscale or YCbCr (since Y == gray).
	278	*/
	279
	280	METHODDEF(void)
	281	grayscale_convert (j_compress_ptr cinfo,
	282	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	283	JDIMENSION output_row, int num_rows)
	284	{
	285	register JSAMPROW inptr;
	286	register JSAMPROW outptr;
	287	register JDIMENSION col;
	288	JDIMENSION num_cols = cinfo->image_width;
	289	int instride = cinfo->input_components;
	290
	291	while (--num_rows >= 0) {
	292	inptr = *input_buf++;
	293	outptr = output_buf[0][output_row];
	294	output_row++;
	295	for (col = 0; col < num_cols; col++) {
	296	outptr[col] = inptr[0]; /* don't need GETJSAMPLE() here */
	297	inptr += instride;
	298	}
	299	}
	300	}
	301
	302
	303	/*
	304	* Convert some rows of samples to the JPEG colorspace.
	305	* No colorspace conversion, but change from interleaved
	306	* to separate-planes representation.
	307	*/
	308
	309	METHODDEF(void)
	310	rgb_convert (j_compress_ptr cinfo,
	311	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	312	JDIMENSION output_row, int num_rows)
	313	{
	314	register JSAMPROW inptr;
	315	register JSAMPROW outptr0, outptr1, outptr2;
	316	register JDIMENSION col;
	317	JDIMENSION num_cols = cinfo->image_width;
	318
	319	while (--num_rows >= 0) {
	320	inptr = *input_buf++;
	321	outptr0 = output_buf[0][output_row];
	322	outptr1 = output_buf[1][output_row];
	323	outptr2 = output_buf[2][output_row];
	324	output_row++;
	325	for (col = 0; col < num_cols; col++) {
	326	/* We can dispense with GETJSAMPLE() here */
	327	outptr0[col] = inptr[RGB_RED];
	328	outptr1[col] = inptr[RGB_GREEN];
	329	outptr2[col] = inptr[RGB_BLUE];
	330	inptr += RGB_PIXELSIZE;
	331	}
	332	}
	333	}
	334
	335
	336	/*
	337	* Convert some rows of samples to the JPEG colorspace.
	338	* This version handles multi-component colorspaces without conversion.
	339	* We assume input_components == num_components.
	340	*/
	341
	342	METHODDEF(void)
	343	null_convert (j_compress_ptr cinfo,
	344	JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
	345	JDIMENSION output_row, int num_rows)
	346	{
	347	register JSAMPROW inptr;
	348	register JSAMPROW outptr;
	349	register JDIMENSION col;
	350	register int ci;
	351	int nc = cinfo->num_components;
	352	JDIMENSION num_cols = cinfo->image_width;
	353
	354	while (--num_rows >= 0) {
	355	/* It seems fastest to make a separate pass for each component. */
	356	for (ci = 0; ci < nc; ci++) {
	357	inptr = *input_buf;
	358	outptr = output_buf[ci][output_row];
	359	for (col = 0; col < num_cols; col++) {
	360	outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
	361	inptr += nc;
	362	}
	363	}
	364	input_buf++;
	365	output_row++;
	366	}
	367	}
	368
	369
	370	/*
	371	* Empty method for start_pass.
	372	*/
	373
	374	METHODDEF(void)
	375	null_method (j_compress_ptr cinfo)
	376	{
	377	/* no work needed */
	378	}
	379
	380
	381	/*
	382	* Module initialization routine for input colorspace conversion.
	383	*/
	384
	385	GLOBAL(void)
	386	jinit_color_converter (j_compress_ptr cinfo)
	387	{
	388	my_cconvert_ptr cconvert;
	389
	390	cconvert = (my_cconvert_ptr)
	391	(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
	392	SIZEOF(my_color_converter));
	393	cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
	394	/* set start_pass to null method until we find out differently */
	395	cconvert->pub.start_pass = null_method;
	396
	397	/* Make sure input_components agrees with in_color_space */
	398	switch (cinfo->in_color_space) {
	399	case JCS_GRAYSCALE:
	400	if (cinfo->input_components != 1)
	401	ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
	402	break;
	403
	404	case JCS_RGB:
	405	if (cinfo->input_components != RGB_PIXELSIZE)
	406	ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
	407	break;
	408
	409	case JCS_YCbCr:
	410	if (cinfo->input_components != 3)
	411	ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
	412	break;
	413
	414	case JCS_CMYK:
	415	case JCS_YCCK:
	416	if (cinfo->input_components != 4)
	417	ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
	418	break;
	419
	420	default: /* JCS_UNKNOWN can be anything */
	421	if (cinfo->input_components < 1)
	422	ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
	423	break;
	424	}
	425
	426	/* Check num_components, set conversion method based on requested space */
	427	switch (cinfo->jpeg_color_space) {
	428	case JCS_GRAYSCALE:
	429	if (cinfo->num_components != 1)
	430	ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
	431	if (cinfo->in_color_space == JCS_GRAYSCALE \|\|
	432	cinfo->in_color_space == JCS_YCbCr)
	433	cconvert->pub.color_convert = grayscale_convert;
	434	else if (cinfo->in_color_space == JCS_RGB) {
	435	cconvert->pub.start_pass = rgb_ycc_start;
	436	cconvert->pub.color_convert = rgb_gray_convert;
	437	} else
	438	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	439	break;
	440
	441	case JCS_RGB:
	442	if (cinfo->num_components != 3)
	443	ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
	444	if (cinfo->in_color_space == JCS_RGB)
	445	cconvert->pub.color_convert = rgb_convert;
	446	else
	447	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	448	break;
	449
	450	case JCS_YCbCr:
	451	if (cinfo->num_components != 3)
	452	ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
	453	if (cinfo->in_color_space == JCS_RGB) {
	454	cconvert->pub.start_pass = rgb_ycc_start;
	455	cconvert->pub.color_convert = rgb_ycc_convert;
	456	} else if (cinfo->in_color_space == JCS_YCbCr)
	457	cconvert->pub.color_convert = null_convert;
	458	else
	459	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	460	break;
	461
	462	case JCS_CMYK:
	463	if (cinfo->num_components != 4)
	464	ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
	465	if (cinfo->in_color_space == JCS_CMYK)
	466	cconvert->pub.color_convert = null_convert;
	467	else
	468	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	469	break;
	470
	471	case JCS_YCCK:
	472	if (cinfo->num_components != 4)
	473	ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
	474	if (cinfo->in_color_space == JCS_CMYK) {
	475	cconvert->pub.start_pass = rgb_ycc_start;
	476	cconvert->pub.color_convert = cmyk_ycck_convert;
	477	} else if (cinfo->in_color_space == JCS_YCCK)
	478	cconvert->pub.color_convert = null_convert;
	479	else
	480	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	481	break;
	482
	483	default: /* allow null conversion of JCS_UNKNOWN */
	484	if (cinfo->jpeg_color_space != cinfo->in_color_space \|\|
	485	cinfo->num_components != cinfo->input_components)
	486	ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
	487	cconvert->pub.color_convert = null_convert;
	488	break;
	489	}
	490	}