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/*
* Copyright (c) 2006-2009, Google Inc. All rights reserved.
* Copyright (c) 2009 Torch Mobile, Inc. All rights reserved.
* Copyright (C) Research In Motion Limited 2009-2010. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "PNGImageEncoder.h"
#include "IntSize.h"
#include "png.h"
#include <wtf/Vector.h>
namespace WebCore {
// Encoder --------------------------------------------------------------------
//
// This section of the code is based on nsPNGEncoder.cpp in Mozilla
// (Copyright 2005 Google Inc.)
// Passed around as the io_ptr in the png structs so our callbacks know where
// to write data.
struct PNGEncoderState {
PNGEncoderState(Vector<char>* o) : m_dump(o) {}
Vector<char>* m_dump;
};
// Called by libpng to flush its internal buffer to ours.
void encoderWriteCallback(png_structp png, png_bytep data, png_size_t size)
{
PNGEncoderState* state = static_cast<PNGEncoderState*>(png_get_io_ptr(png));
ASSERT(state->m_dump);
size_t oldSize = state->m_dump->size();
state->m_dump->resize(oldSize + size);
char* destination = state->m_dump->data() + oldSize;
memcpy(destination, data, size);
}
// Automatically destroys the given write structs on destruction to make
// cleanup and error handling code cleaner.
class PNGWriteStructDestroyer {
public:
PNGWriteStructDestroyer(png_struct** ps, png_info** pi)
: m_pngStruct(ps)
, m_pngInfo(pi)
{
}
~PNGWriteStructDestroyer()
{
png_destroy_write_struct(m_pngStruct, m_pngInfo);
}
private:
png_struct** m_pngStruct;
png_info** m_pngInfo;
};
bool compressRGBABigEndianToPNG(unsigned char* rgbaBigEndianData, const IntSize& size, Vector<char>& pngData)
{
png_struct* pngPtr = png_create_write_struct(PNG_LIBPNG_VER_STRING, png_voidp_NULL, png_error_ptr_NULL, png_error_ptr_NULL);
if (!pngPtr)
return false;
png_info* infoPtr = png_create_info_struct(pngPtr);
if (!infoPtr) {
png_destroy_write_struct(&pngPtr, 0);
return false;
}
PNGWriteStructDestroyer destroyer(&pngPtr, &infoPtr);
// The destroyer will ensure that the structures are cleaned up in this
// case, even though we may get here as a jump from random parts of the
// PNG library called below.
if (setjmp(png_jmpbuf(pngPtr)))
return false;
// Set our callback for libpng to give us the data.
PNGEncoderState state(&pngData);
png_set_write_fn(pngPtr, &state, encoderWriteCallback, 0);
int pngOutputColorType = PNG_COLOR_TYPE_RGB_ALPHA;
png_set_IHDR(pngPtr, infoPtr, size.width(), size.height(), 8, pngOutputColorType,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,
PNG_FILTER_TYPE_DEFAULT);
png_write_info(pngPtr, infoPtr);
unsigned bytesPerRow = size.width() * 4;
for (unsigned y = 0; y < size.height(); ++y) {
png_write_row(pngPtr, rgbaBigEndianData);
rgbaBigEndianData += bytesPerRow;
}
png_write_end(pngPtr, infoPtr);
return true;
}
} // namespace WebCore
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