IMAGE: Add codec accuracy options

image/codec-options.h

@@ -0,0 +1,35 @@
+/* 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef IMAGE_CODEC_OPTIONS_H
+#define IMAGE_CODEC_OPTIONS_H
+
+namespace Image {
+
+enum class CodecAccuracy {
+	Fast,
+	Default,
+	Accurate,
+};
+
+} // End of namespace Image
+
+#endif

image/codecs/codec.h

@@ -25,6 +25,8 @@
 #include "graphics/surface.h"
 #include "graphics/pixelformat.h"
 
+#include "image/codec-options.h"
+
 namespace Common {
 class SeekableReadStream;
 }
@@ -116,6 +118,11 @@ public:
 	 */
 	virtual void setDither(DitherType type, const byte *palette) {}
 
+	/**
+	 * Set the decoding accuracy of the codec, if supported
+	 */
+	virtual void setCodecAccuracy(CodecAccuracy accuracy) {}
+
 	/**
 	 * Create a dither table, as used by QuickTime codecs.
 	 */

image/codecs/mjpeg.cpp

@@ -46,6 +46,7 @@ MJPEGDecoder::MJPEGDecoder() : Codec() {
 		_pixelFormat = Graphics::PixelFormat(4, 8, 8, 8, 8, 8, 16, 24, 0);
 
 	_surface = 0;
+	_accuracy = CodecAccuracy::Default;
 }
 
 MJPEGDecoder::~MJPEGDecoder() {
@@ -204,6 +205,7 @@ const Graphics::Surface *MJPEGDecoder::decodeFrame(Common::SeekableReadStream &s
 
 	Common::MemoryReadStream convertedStream(data, outputSize, DisposeAfterUse::YES);
 	JPEGDecoder jpeg;
+	jpeg.setCodecAccuracy(_accuracy);
 	jpeg.setOutputPixelFormat(_pixelFormat);
 
 	if (!jpeg.loadStream(convertedStream)) {
@@ -224,4 +226,8 @@ const Graphics::Surface *MJPEGDecoder::decodeFrame(Common::SeekableReadStream &s
 	return _surface;
 }
 
+void MJPEGDecoder::setCodecAccuracy(CodecAccuracy accuracy) {
+	_accuracy = accuracy;
+}
+
 } // End of namespace Image

image/codecs/mjpeg.h

@@ -46,12 +46,14 @@ public:
 	~MJPEGDecoder() override;
 
 	const Graphics::Surface *decodeFrame(Common::SeekableReadStream &stream) override;
+	void setCodecAccuracy(CodecAccuracy accuracy) override;
 	Graphics::PixelFormat getPixelFormat() const override { return _pixelFormat; }
 	bool setOutputPixelFormat(const Graphics::PixelFormat &format) override { _pixelFormat = format; return true; }
 
 private:
 	Graphics::PixelFormat _pixelFormat;
 	Graphics::Surface *_surface;
+	CodecAccuracy _accuracy;
 };
 
 } // End of namespace Image

image/jpeg.cpp

@@ -47,6 +47,7 @@ namespace Image {
 JPEGDecoder::JPEGDecoder() :
 		_surface(),
 		_colorSpace(kColorSpaceRGB),
+		_accuracy(CodecAccuracy::Default),
 		_requestedPixelFormat(getByteOrderRgbPixelFormat()) {
 }
 
@@ -77,6 +78,10 @@ const Graphics::Surface *JPEGDecoder::decodeFrame(Common::SeekableReadStream &st
 	return getSurface();
 }
 
+void JPEGDecoder::setCodecAccuracy(CodecAccuracy accuracy) {
+	_accuracy = accuracy;
+}
+
 Graphics::PixelFormat JPEGDecoder::getPixelFormat() const {
 	return _surface.format;
 }
@@ -243,6 +248,11 @@ bool JPEGDecoder::loadStream(Common::SeekableReadStream &stream) {
 	// Initialize the decompression structure
 	jpeg_create_decompress(&cinfo);
 
+	if (_accuracy <= CodecAccuracy::Fast)
+		cinfo.dct_method = JDCT_FASTEST;
+	else if (_accuracy >= CodecAccuracy::Accurate)
+		cinfo.dct_method = JDCT_ISLOW;
+
 	// Initialize our buffer handling
 	jpeg_scummvm_src(&cinfo, &stream);
 

image/jpeg.h

@@ -58,6 +58,7 @@ public:
 
 	// Codec API
 	const Graphics::Surface *decodeFrame(Common::SeekableReadStream &stream) override;
+	void setCodecAccuracy(CodecAccuracy accuracy) override;
 	Graphics::PixelFormat getPixelFormat() const override;
 	bool setOutputPixelFormat(const Graphics::PixelFormat &format) override { _requestedPixelFormat = format; return true; }
 
@@ -100,6 +101,7 @@ private:
 	Graphics::Surface _surface;
 	ColorSpace _colorSpace;
 	Graphics::PixelFormat _requestedPixelFormat;
+	CodecAccuracy _accuracy;
 
 	Graphics::PixelFormat getByteOrderRgbPixelFormat() const;
 };