4 files changed, 688 insertions, 0 deletions

diff --git a/linden/indra/llimage/llimagepng.cpp b/linden/indra/llimage/llimagepng.cpp
new file mode 100644
index 0000000..d6b62a8
--- /dev/null
+++ b/linden/indra/llimage/llimagepng.cpp
@@ -0,0 +1,147 @@
+/*
+ * @file llimagepng.cpp
+ * @brief LLImageFormatted glue to encode / decode PNG files.
+ *
+ * Copyright (c) 2007 Peekay Semyorka.
+ * Copyright (c) 2007-2007, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ */
+
+#include "linden_common.h"
+#include "stdtypes.h"
+#include "llerror.h"
+
+#include "llimage.h"
+#include "llpngwrapper.h"
+#include "llimagepng.h"
+
+// ---------------------------------------------------------------------------
+// LLImagePNG
+// ---------------------------------------------------------------------------
+LLImagePNG::LLImagePNG()
+    : LLImageFormatted(IMG_CODEC_PNG),
+          mTmpWriteBuffer(NULL)
+{
+}
+
+LLImagePNG::~LLImagePNG()
+{
+        if (mTmpWriteBuffer)
+        {
+                delete[] mTmpWriteBuffer;
+        }
+}
+
+// Virtual
+// Parse PNG image information and set the appropriate
+// width, height and component (channel) information.
+BOOL LLImagePNG::updateData()
+{
+    resetLastError();
+
+    // Check to make sure that this instance has been initialized with data
+    if (!getData() || (0 == getDataSize()))
+    {
+        setLastError("Uninitialized instance of LLImagePNG");
+        return FALSE;
+    }
+
+        // Decode the PNG data and extract sizing information
+        LLPngWrapper pngWrapper;
+        LLPngWrapper::ImageInfo infop;
+        if (! pngWrapper.readPng(getData(), NULL, &infop))
+        {
+                setLastError(pngWrapper.getErrorMessage());
+                return FALSE;
+        }
+
+        setSize(infop.mWidth, infop.mHeight, infop.mComponents);
+
+        return TRUE;
+}
+
+// Virtual
+// Decode an in-memory PNG image into the raw RGB or RGBA format
+// used within SecondLife.
+BOOL LLImagePNG::decode(LLImageRaw* raw_image, F32 decode_time)
+{
+        llassert_always(raw_image);
+
+    resetLastError();
+
+    // Check to make sure that this instance has been initialized with data
+    if (!getData() || (0 == getDataSize()))
+    {
+        setLastError("LLImagePNG trying to decode an image with no data!");
+        return FALSE;
+    }
+
+        // Decode the PNG data into the raw image
+        LLPngWrapper pngWrapper;
+        if (! pngWrapper.readPng(getData(), raw_image))
+        {
+                setLastError(pngWrapper.getErrorMessage());
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+// Virtual
+// Encode the in memory RGB image into PNG format.
+BOOL LLImagePNG::encode(const LLImageRaw* raw_image, F32 encode_time)
+{
+        llassert_always(raw_image);
+
+    resetLastError();
+
+        // Image logical size
+        setSize(raw_image->getWidth(), raw_image->getHeight(), raw_image->getComponents());
+
+        // Temporary buffer to hold the encoded image. Note: the final image
+        // size should be much smaller due to compression.
+        if (mTmpWriteBuffer)
+        {
+                delete[] mTmpWriteBuffer;
+        }
+        U32 bufferSize = getWidth() * getHeight() * getComponents() + 1024;
+    U8* mTmpWriteBuffer = new U8[ bufferSize ];
+
+        // Delegate actual encoding work to wrapper
+        LLPngWrapper pngWrapper;
+        if (! pngWrapper.writePng(raw_image, mTmpWriteBuffer))
+        {
+                setLastError(pngWrapper.getErrorMessage());
+                return FALSE;
+        }
+
+        // Resize internal buffer and copy from temp
+        U32 encodedSize = pngWrapper.getFinalSize();
+        allocateData(encodedSize);
+        memcpy(getData(), mTmpWriteBuffer, encodedSize);
+
+        delete[] mTmpWriteBuffer;
+
+        return TRUE;
+}
+
diff --git a/linden/indra/llimage/llimagepng.h b/linden/indra/llimage/llimagepng.h
new file mode 100644
index 0000000..abdff7c
--- /dev/null
+++ b/linden/indra/llimage/llimagepng.h
@@ -0,0 +1,51 @@
+/* 
+ * @file llimagepng.h
+ *
+ * Copyright (c) 2007 Peekay Semyorka.
+ * Copyright (c) 2007-2007, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ */
+
+#ifndef LL_LLIMAGEPNG_H
+#define LL_LLIMAGEPNG_H
+
+#include "stdtypes.h"
+#include "llimage.h"
+
+class LLImagePNG : public LLImageFormatted
+{
+protected:
+        ~LLImagePNG();
+
+public:
+        LLImagePNG();
+
+        BOOL updateData();
+        BOOL decode(LLImageRaw* raw_image, F32 decode_time = 0.0);
+        BOOL encode(const LLImageRaw* raw_image, F32 encode_time = 0.0);
+
+private:
+        U8* mTmpWriteBuffer;
+};
+
+#endif
diff --git a/linden/indra/llimage/llpngwrapper.cpp b/linden/indra/llimage/llpngwrapper.cpp
new file mode 100644
index 0000000..52616d1
--- /dev/null
+++ b/linden/indra/llimage/llpngwrapper.cpp
@@ -0,0 +1,388 @@
+/*
+ * @file llpngwrapper.cpp
+ * @brief Encapsulates libpng read/write functionality.
+ *
+ * Copyright (c) 2007 Peekay Semyorka.
+ * Copyright (c) 2007-2007, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ */
+
+#include "linden_common.h"
+#include "stdtypes.h"
+#include "llerror.h"
+
+#include "llimage.h"
+#include "llpngwrapper.h"
+
+// ---------------------------------------------------------------------------
+// LLPngWrapper
+// ---------------------------------------------------------------------------
+
+LLPngWrapper::LLPngWrapper()
+        : mReadPngPtr( NULL ),
+      mReadInfoPtr( NULL ),
+          mWritePngPtr( NULL ),
+          mWriteInfoPtr( NULL ),
+          mRowPointers( NULL ),
+          mBitDepth( 0 ),
+          mColorType( 0 ),
+          mChannels( 0 ),
+          mInterlaceType( 0 ),
+          mCompressionType( 0 ),
+          mFilterMethod( 0 ),
+          mFinalSize( 0 )
+{
+}
+
+LLPngWrapper::~LLPngWrapper()
+{
+        releaseResources();
+}
+
+// Checks the src for a valid PNG header
+BOOL LLPngWrapper::isValidPng(U8* src)
+{
+        const int PNG_BYTES_TO_CHECK = 8;
+
+        int sig = png_sig_cmp((png_bytep)src, (png_size_t)0, PNG_BYTES_TO_CHECK);
+        if (sig != 0)
+        {
+                mErrorMessage = "Invalid or corrupt PNG file";
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+// Called by the libpng library when a fatal encoding or decoding error
+// occurs.  We simply throw the error message and let our try/catch
+// block clean up.
+void LLPngWrapper::errorHandler(png_structp png_ptr, png_const_charp msg)
+{
+        throw msg;
+}
+
+// Called by the libpng library when reading (decoding) the PNG file. We
+// copy the PNG data from our internal buffer into the PNG's data buffer.
+void LLPngWrapper::readDataCallback(png_structp png_ptr, png_bytep dest, png_size_t length)
+{
+        PngDataInfo *dataInfo = (PngDataInfo *) png_get_io_ptr(png_ptr);
+        U8 *src = &dataInfo->mData[dataInfo->mOffset];
+        memcpy(dest, src, length);
+        dataInfo->mOffset += static_cast<U32>(length);
+}
+
+// Called by the libpng library when writing (encoding) the PNG file. We
+// copy the encoded result into our data buffer.
+void LLPngWrapper::writeDataCallback(png_structp png_ptr, png_bytep src, png_size_t length)
+{
+        PngDataInfo *dataInfo = (PngDataInfo *) png_get_io_ptr(png_ptr);
+        U8 *dest = &dataInfo->mData[dataInfo->mOffset];
+        memcpy(dest, src, length);
+        dataInfo->mOffset += static_cast<U32>(length);
+}
+
+// Flush the write output pointer
+void LLPngWrapper::writeFlush(png_structp png_ptr)
+{
+        // no-op since we're just writing to memory
+}
+
+// Read the PNG file using the libpng.  The low-level interface is used here
+// because we want to do various transformations (including setting the
+// matte background if any, and applying gama) which can't be done with
+// the high-level interface. The scanline also begins at the bottom of
+// the image (per SecondLife conventions) instead of at the top, so we
+// must assign row-pointers in "reverse" order.
+BOOL LLPngWrapper::readPng(U8* src, LLImageRaw* rawImage, ImageInfo *infop)
+{
+        try
+        {
+                // Create and initialize the png structures
+                mReadPngPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+                        this, &errorHandler, NULL);
+                if (mReadPngPtr == NULL)
+                {
+                        throw "Problem creating png read structure";
+                }
+
+                // Allocate/initialize the memory for image information.
+                mReadInfoPtr = png_create_info_struct(mReadPngPtr);
+
+                // Set up the input control
+                PngDataInfo dataPtr;
+                dataPtr.mData = src;
+                dataPtr.mOffset = 0;
+
+                png_set_read_fn(mReadPngPtr, &dataPtr, &readDataCallback);
+                png_set_sig_bytes(mReadPngPtr, 0);
+
+                // setup low-level read and get header information
+                png_read_info(mReadPngPtr, mReadInfoPtr);
+                png_get_IHDR(mReadPngPtr, mReadInfoPtr, &mWidth, &mHeight,
+                        &mBitDepth, &mColorType, &mInterlaceType,
+                        &mCompressionType, &mFilterMethod);
+
+                // Normalize the image, then get updated image information
+                // after transformations have been applied
+                normalizeImage();
+                updateMetaData();
+
+                // If a raw object is supplied, read the PNG image into its
+                // data space
+                if (rawImage != NULL)
+                {
+                        rawImage->resize(static_cast<U16>(mWidth),
+                                static_cast<U16>(mHeight), mChannels);
+                        U8 *dest = rawImage->getData();
+                        int offset = mWidth * mChannels;
+
+                        // Set up the row pointers and read the image
+                        mRowPointers = new U8* [mHeight];
+                        for (U32 i=0; i < mHeight; i++)
+                        {
+                                mRowPointers[i] = &dest[(mHeight-i-1)*offset];
+                        }
+
+                        png_read_image(mReadPngPtr, mRowPointers);
+
+                        // Finish up, ensures all metadata are updated
+                        png_read_end(mReadPngPtr, NULL);
+                }
+
+                // If an info object is supplied, copy the relevant info
+                if (infop != NULL)
+                {
+                        infop->mHeight = static_cast<U16>(mHeight);
+                        infop->mWidth = static_cast<U16>(mWidth);
+                        infop->mComponents = mChannels;
+                }
+
+                mFinalSize = dataPtr.mOffset;
+        }
+        catch (png_const_charp msg)
+        {
+                mErrorMessage = msg;
+                releaseResources();
+                return (FALSE);
+        }
+
+        // Clean up and return
+        releaseResources();
+        return (TRUE);
+}
+
+// Do transformations to normalize the input to 8-bpp RGBA
+void LLPngWrapper::normalizeImage()
+{
+        //              1. Expand any palettes
+        //              2. Convert grayscales to RGB
+        //              3. Create alpha layer from transparency
+        //              4. Ensure 8-bpp for all images
+        //              5. Apply background matte if any
+        //              6. Set (or guess) gamma
+
+        if (mColorType == PNG_COLOR_TYPE_PALETTE)
+        {
+                png_set_palette_to_rgb(mReadPngPtr);
+        }
+    if (mColorType == PNG_COLOR_TYPE_GRAY && mBitDepth < 8)
+        {
+                png_set_gray_1_2_4_to_8(mReadPngPtr);
+        }
+        if (mColorType == PNG_COLOR_TYPE_GRAY
+                || mColorType == PNG_COLOR_TYPE_GRAY_ALPHA)
+        {
+                png_set_gray_to_rgb(mReadPngPtr);
+        }
+        if (png_get_valid(mReadPngPtr, mReadInfoPtr, PNG_INFO_tRNS))
+        {
+                png_set_tRNS_to_alpha(mReadPngPtr);
+        }
+        if (mBitDepth < 8)
+        {
+                png_set_packing(mReadPngPtr);
+        }
+        else if (mBitDepth == 16)
+        {
+                png_set_strip_16(mReadPngPtr);
+        }
+        mHasBKGD = png_get_bKGD(mReadPngPtr, mReadInfoPtr, &mBackgroundColor);
+        if (mHasBKGD)
+        {
+                png_set_background(mReadPngPtr, mBackgroundColor,
+                        PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
+        }
+
+#if LL_DARWIN
+        const F64 SCREEN_GAMMA = 1.8;
+#else
+        const F64 SCREEN_GAMMA = 2.2;
+#endif
+
+        if (png_get_gAMA(mReadPngPtr, mReadInfoPtr, &mGamma))
+        {
+                png_set_gamma(mReadPngPtr, SCREEN_GAMMA, mGamma);
+        }
+        else
+        {
+                png_set_gamma(mReadPngPtr, SCREEN_GAMMA, 1/SCREEN_GAMMA);
+        }
+}
+
+// Read out the image meta-data
+void LLPngWrapper::updateMetaData()
+{
+        png_read_update_info(mReadPngPtr, mReadInfoPtr);
+    mWidth = png_get_image_width(mReadPngPtr, mReadInfoPtr);
+    mHeight = png_get_image_height(mReadPngPtr, mReadInfoPtr);
+    mBitDepth = png_get_bit_depth(mReadPngPtr, mReadInfoPtr);
+    mColorType = png_get_color_type(mReadPngPtr, mReadInfoPtr);
+        mChannels = png_get_channels(mReadPngPtr, mReadInfoPtr);
+        mHasBKGD = png_get_bKGD(mReadPngPtr, mReadInfoPtr, &mBackgroundColor);
+}
+
+// Method to write raw image into PNG at dest. The raw scanline begins
+// at the bottom of the image per SecondLife conventions.
+BOOL LLPngWrapper::writePng(const LLImageRaw* rawImage, U8* dest)
+{
+        try
+        {
+                S8 numComponents = rawImage->getComponents();
+                switch (numComponents)
+                {
+                case 1:
+                        mColorType = PNG_COLOR_TYPE_GRAY;
+                        break;
+                case 2:
+                        mColorType = PNG_COLOR_TYPE_GRAY_ALPHA;
+                        break;
+                case 3:
+                        mColorType = PNG_COLOR_TYPE_RGB;
+                        break;
+                case 4:
+                        mColorType = PNG_COLOR_TYPE_RGB_ALPHA;
+                        break;
+                default:
+                        mColorType = -1;
+                }
+
+                if (mColorType == -1)
+                {
+                        throw "Unsupported image: unexpected number of channels";
+                }
+
+                mWritePngPtr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+                        NULL, &errorHandler, NULL);
+                if (!mWritePngPtr)
+                {
+                        throw "Problem creating png write structure";
+                }
+
+                mWriteInfoPtr = png_create_info_struct(mWritePngPtr);
+
+                // Setup write function
+                PngDataInfo dataPtr;
+                dataPtr.mData = dest;
+                dataPtr.mOffset = 0;
+                png_set_write_fn(mWritePngPtr, &dataPtr, &writeDataCallback, &writeFlush);
+
+                // Setup image params
+                mWidth = rawImage->getWidth();
+                mHeight = rawImage->getHeight();
+                mBitDepth = 8;  // Fixed to 8-bpp in SL
+                mChannels = numComponents;
+                mInterlaceType = PNG_INTERLACE_NONE;
+                mCompressionType = PNG_COMPRESSION_TYPE_DEFAULT;
+                mFilterMethod = PNG_FILTER_TYPE_DEFAULT;
+
+                // Write header
+                png_set_IHDR(mWritePngPtr, mWriteInfoPtr, mWidth, mHeight,
+                        mBitDepth, mColorType, mInterlaceType,
+                        mCompressionType, mFilterMethod);
+
+                // Get data and compute row size
+                const U8* data = rawImage->getData();
+                int offset = mWidth * mChannels;
+
+                // Ready to write, start with the header
+                png_write_info(mWritePngPtr, mWriteInfoPtr);
+
+                // Write image (sorry, must const-cast for libpng)
+                const U8 * rowPointer;
+                for (U32 i=0; i < mHeight; i++)
+                {
+                        rowPointer = &data[(mHeight-1-i)*offset];
+                        png_write_row(mWritePngPtr, const_cast<png_bytep>(rowPointer));
+                }
+
+                // Finish up
+                png_write_end(mWritePngPtr, mWriteInfoPtr);
+                mFinalSize = dataPtr.mOffset;
+        }
+        catch (png_const_charp msg)
+        {
+                mErrorMessage = msg;
+                releaseResources();
+                return (FALSE);
+        }
+
+        releaseResources();
+        return TRUE;
+}
+
+// Cleanup various internal structures
+void LLPngWrapper::releaseResources()
+{
+        if (mReadPngPtr || mReadInfoPtr)
+        {
+                png_destroy_read_struct(&mReadPngPtr, &mReadInfoPtr, png_infopp_NULL);
+                mReadPngPtr = NULL;
+                mReadInfoPtr = NULL;
+        }
+
+        if (mWritePngPtr || mWriteInfoPtr)
+        {
+                png_destroy_write_struct(&mWritePngPtr, &mWriteInfoPtr);
+                mWritePngPtr = NULL;
+                mWriteInfoPtr = NULL;
+        }
+
+        if (mRowPointers)
+        {
+                delete[] mRowPointers;
+                mRowPointers = NULL;
+        }
+}
+
+// Get final image size after compression
+U32 LLPngWrapper::getFinalSize()
+{
+        return mFinalSize;
+}
+
+// Get last error message, if any
+LLString LLPngWrapper::getErrorMessage()
+{
+        return mErrorMessage;
+}
diff --git a/linden/indra/llimage/llpngwrapper.h b/linden/indra/llimage/llpngwrapper.h
new file mode 100644
index 0000000..1b5b97f
--- /dev/null
+++ b/linden/indra/llimage/llpngwrapper.h
@@ -0,0 +1,102 @@
+/*
+ * @file llpngwrapper.h
+ *
+ * Copyright (c) 2007 Peekay Semyorka.
+ * Copyright (c) 2007-2007, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlife.com/developers/opensource/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at http://secondlife.com/developers/opensource/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ */
+
+#ifndef LL_LLPNGWRAPPER_H
+#define LL_LLPNGWRAPPER_H
+
+#include "libpng12/png.h"
+#include "llimage.h"
+
+class LLPngWrapper
+{
+public:
+        LLPngWrapper();
+        virtual ~LLPngWrapper();
+
+public:
+        struct ImageInfo
+        {
+                U16 mWidth;
+                U16 mHeight;
+                S8  mComponents;
+        };
+
+        BOOL isValidPng(U8* src);
+        BOOL readPng(U8* src, LLImageRaw* rawImage, ImageInfo *infop = NULL);
+        BOOL writePng(const LLImageRaw* rawImage, U8* dst);
+        U32  getFinalSize();
+        LLString getErrorMessage();
+
+protected:
+        void normalizeImage();
+        void updateMetaData();
+
+private:
+
+        // Structure for writing/reading PNG data to/from memory
+        // as opposed to using a file.
+        struct PngDataInfo
+        {
+                U8 *mData;
+                U32 mOffset;
+        };
+
+        static void writeFlush(png_structp png_ptr);
+        static void errorHandler(png_structp png_ptr, png_const_charp msg);
+        static void readDataCallback(png_structp png_ptr, png_bytep dest, png_size_t length);
+        static void writeDataCallback(png_structp png_ptr, png_bytep src, png_size_t length);
+
+        void releaseResources();
+
+        png_structp mReadPngPtr;
+        png_infop mReadInfoPtr;
+        png_structp mWritePngPtr;
+        png_infop mWriteInfoPtr;
+
+        U8 **mRowPointers;
+
+        png_uint_32 mWidth;
+        png_uint_32 mHeight;
+        S32 mBitDepth;
+        S32 mColorType;
+        S32 mChannels;
+        S32 mInterlaceType;
+        S32 mCompressionType;
+        S32 mFilterMethod;
+
+        U32 mFinalSize;
+
+        BOOL mHasBKGD;
+        png_color_16p mBackgroundColor;
+
+        F64 mGamma;
+
+        LLString mErrorMessage;
+};
+
+#endif