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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
// Since we need to work with libpng here, we need to allow all symbols
// to avoid compilation issues.
#define FORBIDDEN_SYMBOL_ALLOW_ALL
#include "common/scummsys.h"
#ifdef USE_PNG
#include <png.h>
#endif
#include "graphics/decoders/png.h"
#include "graphics/pixelformat.h"
#include "graphics/surface.h"
#include "common/stream.h"
namespace Graphics {
PNGDecoder::PNGDecoder() : _outputSurface(0), _palette(0), _paletteColorCount(0), _stream(0) {
}
PNGDecoder::~PNGDecoder() {
destroy();
}
void PNGDecoder::destroy() {
if (_outputSurface) {
_outputSurface->free();
delete _outputSurface;
_outputSurface = 0;
}
delete[] _palette;
_palette = NULL;
}
#ifdef USE_PNG
// libpng-error-handling:
void pngError(png_structp pngptr, png_const_charp errorMsg) {
error("%s", errorMsg);
}
void pngWarning(png_structp pngptr, png_const_charp warningMsg) {
warning("%s", warningMsg);
}
// libpng-I/O-helper:
void pngReadFromStream(png_structp pngPtr, png_bytep data, png_size_t length) {
void *readIOptr = png_get_io_ptr(pngPtr);
Common::SeekableReadStream *stream = (Common::SeekableReadStream *)readIOptr;
stream->read(data, length);
}
#endif
/*
* This code is based on Broken Sword 2.5 engine
*
* Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
*
* Licensed under GNU GPL v2
*
*/
bool PNGDecoder::loadStream(Common::SeekableReadStream &stream) {
#ifdef USE_PNG
destroy();
_stream = &stream;
// First, check the PNG signature
if (_stream->readUint32BE() != MKTAG(0x89, 'P', 'N', 'G')) {
delete _stream;
return false;
}
if (_stream->readUint32BE() != MKTAG(0x0d, 0x0a, 0x1a, 0x0a)) {
delete _stream;
return false;
}
// The following is based on the guide provided in:
//http://www.libpng.org/pub/png/libpng-1.2.5-manual.html#section-3
//http://www.libpng.org/pub/png/libpng-1.4.0-manual.pdf
// along with the png-loading code used in the sword25-engine.
png_structp pngPtr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!pngPtr) {
delete _stream;
return false;
}
png_infop infoPtr = png_create_info_struct(pngPtr);
if (!infoPtr) {
png_destroy_read_struct(&pngPtr, NULL, NULL);
delete _stream;
return false;
}
png_infop endInfo = png_create_info_struct(pngPtr);
if (!endInfo) {
png_destroy_read_struct(&pngPtr, &infoPtr, NULL);
delete _stream;
return false;
}
png_set_error_fn(pngPtr, NULL, pngError, pngWarning);
// TODO: The manual says errors should be handled via setjmp
png_set_read_fn(pngPtr, _stream, pngReadFromStream);
png_set_crc_action(pngPtr, PNG_CRC_DEFAULT, PNG_CRC_WARN_USE);
// We already verified the PNG-header
png_set_sig_bytes(pngPtr, 8);
// Read PNG header
png_read_info(pngPtr, infoPtr);
// No handling for unknown chunks yet.
int bitDepth, colorType, width, height, interlaceType;
png_uint_32 w, h;
png_get_IHDR(pngPtr, infoPtr, &w, &h, &bitDepth, &colorType, &interlaceType, NULL, NULL);
width = w;
height = h;
// Allocate memory for the final image data.
// To keep memory framentation low this happens before allocating memory for temporary image data.
_outputSurface = new Graphics::Surface();
// Images of all color formats except PNG_COLOR_TYPE_PALETTE
// will be transformed into ARGB images
if (colorType == PNG_COLOR_TYPE_PALETTE && !png_get_valid(pngPtr, infoPtr, PNG_INFO_tRNS)) {
int numPalette = 0;
png_colorp palette = NULL;
uint32 success = png_get_PLTE(pngPtr, infoPtr, &palette, &numPalette);
if (success != PNG_INFO_PLTE) {
png_destroy_read_struct(&pngPtr, &infoPtr, NULL);
return false;
}
_paletteColorCount = numPalette;
_palette = new byte[_paletteColorCount * 3];
for (int i = 0; i < _paletteColorCount; i++) {
_palette[(i * 3)] = palette[i].red;
_palette[(i * 3) + 1] = palette[i].green;
_palette[(i * 3) + 2] = palette[i].blue;
}
_outputSurface->create(width, height, Graphics::PixelFormat::createFormatCLUT8());
png_set_packing(pngPtr);
} else {
bool isAlpha = (colorType & PNG_COLOR_MASK_ALPHA);
if (png_get_valid(pngPtr, infoPtr, PNG_INFO_tRNS)) {
isAlpha = true;
png_set_expand(pngPtr);
}
_outputSurface->create(width, height, Graphics::PixelFormat(4,
8, 8, 8, isAlpha ? 8 : 0, 24, 16, 8, 0));
if (!_outputSurface->getPixels()) {
error("Could not allocate memory for output image.");
}
if (bitDepth == 16)
png_set_strip_16(pngPtr);
if (bitDepth < 8)
png_set_expand(pngPtr);
if (colorType == PNG_COLOR_TYPE_GRAY ||
colorType == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(pngPtr);
// PNGs are Big-Endian:
#ifdef SCUMM_LITTLE_ENDIAN
png_set_bgr(pngPtr);
png_set_swap_alpha(pngPtr);
if (colorType != PNG_COLOR_TYPE_RGB_ALPHA)
png_set_filler(pngPtr, 0xff, PNG_FILLER_BEFORE);
#else
if (colorType != PNG_COLOR_TYPE_RGB_ALPHA)
png_set_filler(pngPtr, 0xff, PNG_FILLER_AFTER);
#endif
}
// After the transformations have been registered, the image data is read again.
png_set_interlace_handling(pngPtr);
png_read_update_info(pngPtr, infoPtr);
png_get_IHDR(pngPtr, infoPtr, &w, &h, &bitDepth, &colorType, NULL, NULL, NULL);
width = w;
height = h;
if (interlaceType == PNG_INTERLACE_NONE) {
// PNGs without interlacing can simply be read row by row.
for (int i = 0; i < height; i++) {
png_read_row(pngPtr, (png_bytep)_outputSurface->getBasePtr(0, i), NULL);
}
} else {
// PNGs with interlacing require us to allocate an auxillary
// buffer with pointers to all row starts.
// Allocate row pointer buffer
png_bytep *rowPtr = new png_bytep[height];
if (!rowPtr) {
error("Could not allocate memory for row pointers.");
}
// Initialize row pointers
for (int i = 0; i < height; i++)
rowPtr[i] = (png_bytep)_outputSurface->getBasePtr(0, i);
// Read image data
png_read_image(pngPtr, rowPtr);
// Free row pointer buffer
delete[] rowPtr;
}
// Read additional data at the end.
png_read_end(pngPtr, NULL);
// Destroy libpng structures
png_destroy_read_struct(&pngPtr, &infoPtr, &endInfo);
// We no longer need the file stream, thus close it here
_stream = 0;
return true;
#else
return false;
#endif
}
} // End of Graphics namespace
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