1 files changed, 245 insertions, 0 deletions
diff --git a/image/png.cpp b/image/png.cpp
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index 0000000000..158acfa8a5
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+++ b/image/png.cpp
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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 "image/png.h"
+
+#include "graphics/pixelformat.h"
+#include "graphics/surface.h"
+
+#include "common/stream.h"
+
+namespace Image {
+
+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 namespace Image