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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.
*
*/
/**
* @file
* Image decoder used in engines:
* - groovie
* - mohawk
*/
#ifndef GRAPHICS_JPEG_H
#define GRAPHICS_JPEG_H
#include "graphics/surface.h"
#include "graphics/decoders/image_decoder.h"
namespace Common {
class SeekableReadStream;
}
namespace Graphics {
struct PixelFormat;
#define JPEG_MAX_QUANT_TABLES 4
#define JPEG_MAX_HUFF_TABLES 2
class JPEGDecoder : public ImageDecoder {
public:
JPEGDecoder();
~JPEGDecoder();
// ImageDecoder API
void destroy();
bool loadStream(Common::SeekableReadStream &str);
const Surface *getSurface() const;
bool isLoaded() const { return _numComp && _w && _h; }
uint16 getWidth() const { return _w; }
uint16 getHeight() const { return _h; }
const Surface *getComponent(uint c) const;
private:
Common::SeekableReadStream *_stream;
uint16 _w, _h;
uint16 _restartInterval;
// mutable so that we can convert to RGB only during
// a getSurface() call while still upholding the
// const requirement in other ImageDecoders
mutable Graphics::Surface *_rgbSurface;
// Image components
uint8 _numComp;
struct Component {
// Global values
uint8 id;
uint8 factorH;
uint8 factorV;
uint8 quantTableSelector;
// Scan specific values
uint8 DCentropyTableSelector;
uint8 ACentropyTableSelector;
int16 DCpredictor;
// Result image for this component
Surface surface;
};
Component *_components;
// Scan components
uint8 _numScanComp;
Component **_scanComp;
Component *_currentComp;
// Maximum sampling factors, used to calculate the interleaving of the MCU
uint8 _maxFactorV;
uint8 _maxFactorH;
// Quantization tables
uint16 *_quant[JPEG_MAX_QUANT_TABLES];
// Huffman tables
struct HuffmanTable {
uint8 count;
uint8 *values;
uint8 *sizes;
uint16 *codes;
} _huff[2 * JPEG_MAX_HUFF_TABLES];
// Marker read functions
bool readJFIF();
bool readSOF0();
bool readDHT();
bool readSOS();
bool readDQT();
bool readDRI();
// Helper functions
bool readMCU(uint16 xMCU, uint16 yMCU);
bool readDataUnit(uint16 x, uint16 y);
int16 readDC();
void readAC(int16 *out);
int16 readSignedBits(uint8 numBits);
// Huffman decoding
uint8 readHuff(uint8 table);
uint8 readBit();
uint8 _bitsData;
uint8 _bitsNumber;
// Inverse Discrete Cosine Transformation
static void idct1D8x8(int32 src[8], int32 dest[64], int32 ps, int32 half);
static void idct2D8x8(int32 block[64]);
};
} // End of Graphics namespace
#endif // GRAPHICS_JPEG_H
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