GRAPHICS: Implemented a PNG decoder, and set it as default for the sword25 engine

libpng is still needed for PNG encoding (for thumbnails in saved games of sword25), but
since we'll probably drop support for the original saved games anyway, the PNG encoding
code will ultimately be removed

svn-id: r55723

1 files changed, 35 insertions, 2 deletions

diff --git a/engines/sword25/gfx/image/pngloader.cpp b/engines/sword25/gfx/image/pngloader.cpp
index cdff0012c2..f54b45254b 100644
--- a/engines/sword25/gfx/image/pngloader.cpp
+++ b/engines/sword25/gfx/image/pngloader.cpp
@@ -32,13 +32,23 @@
  *
  */
 
+// Define to use ScummVM's PNG decoder, instead of libpng
+#define USE_INTERNAL_PNG_DECODER
+
+#ifndef USE_INTERNAL_PNG_DECODER
 // Disable symbol overrides so that we can use png.h
 #define FORBIDDEN_SYMBOL_ALLOW_ALL
+#endif
 
 #include "common/memstream.h"
 #include "sword25/gfx/image/image.h"
 #include "sword25/gfx/image/pngloader.h"
+#ifndef USE_INTERNAL_PNG_DECODER
 #include <png.h>
+#else
+#include "graphics/pixelformat.h"
+#include "graphics/png.h"
+#endif
 
 namespace Sword25 {
 
@@ -87,6 +97,7 @@ static uint findEmbeddedPNG(const byte *fileDataPtr, uint fileSize) {
 	return static_cast<uint>(stream.pos() + compressedGamedataSize);
 }
 
+#ifndef USE_INTERNAL_PNG_DECODER
 static void png_user_read_data(png_structp png_ptr, png_bytep data, png_size_t length) {
 	const byte **ref = (const byte **)png_get_io_ptr(png_ptr);
 	memcpy(data, *ref, length);
@@ -96,9 +107,10 @@ static void png_user_read_data(png_structp png_ptr, png_bytep data, png_size_t l
 static bool doIsCorrectImageFormat(const byte *fileDataPtr, uint fileSize) {
 	return (fileSize > 8) && png_check_sig(const_cast<byte *>(fileDataPtr), 8);
 }
-
+#endif
 
 bool PNGLoader::doDecodeImage(const byte *fileDataPtr, uint fileSize, byte *&uncompressedDataPtr, int &width, int &height, int &pitch) {
+#ifndef USE_INTERNAL_PNG_DECODER
 	png_structp png_ptr = NULL;
 	png_infop   info_ptr = NULL;
 
@@ -202,7 +214,25 @@ bool PNGLoader::doDecodeImage(const byte *fileDataPtr, uint fileSize, byte *&unc
 
 	// Destroy libpng structures
 	png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
+#else
+	Common::MemoryReadStream *fileStr = new Common::MemoryReadStream(fileDataPtr, fileSize, DisposeAfterUse::NO);
+	Graphics::PNG *png = new Graphics::PNG();
+	if (!png->read(fileStr))	// the fileStr pointer, and thus pFileData will be deleted after this is done
+		error("Error while reading PNG image");	
+
+	Graphics::PixelFormat format = Graphics::PixelFormat(4, 8, 8, 8, 8, 16, 8, 0, 24);
+	Graphics::Surface *pngSurface = png->getSurface(format);
 
+	width = pngSurface->w;
+	height = pngSurface->h;
+	uncompressedDataPtr = new byte[pngSurface->pitch * pngSurface->h];
+	memcpy(uncompressedDataPtr, (byte *)pngSurface->pixels, pngSurface->pitch * pngSurface->h);
+	pngSurface->free();
+
+	delete pngSurface;
+	delete png;
+
+#endif
 	// Signal success
 	return true;
 }
@@ -213,6 +243,7 @@ bool PNGLoader::decodeImage(const byte *fileDataPtr, uint fileSize, byte *&uncom
 }
 
 bool PNGLoader::doImageProperties(const byte *fileDataPtr, uint fileSize, int &width, int &height) {
+#ifndef USE_INTERNAL_PNG_DECODER
 	// Check for valid PNG signature
 	if (!doIsCorrectImageFormat(fileDataPtr, fileSize))
 		return false;
@@ -249,7 +280,9 @@ bool PNGLoader::doImageProperties(const byte *fileDataPtr, uint fileSize, int &w
 
 	// Die Strukturen freigeben
 	png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-
+#else
+	// We don't need to read the image properties here...
+#endif
 	return true;
 
 }