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image/codecs/codec.h

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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 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_CODECS_CODEC_H
+#define IMAGE_CODECS_CODEC_H
+
+#include "graphics/surface.h"
+#include "graphics/pixelformat.h"
+
+#include "image/codec-options.h"
+
+namespace Common {
+class SeekableReadStream;
+}
+
+namespace Image {
+
+/**
+ * An abstract representation of a image codec.
+ *
+ * Unlike ImageDecoder, the entire info for a frame may not be present
+ * within the stream. The codec may rely on the supporting container
+ * for parameters and can also rely on a previous (or future) frame.
+ * When decoding, the previous frame may not destroyed and could be
+ * maintained for use in the next one.
+ *
+ * An ImageDecoder can always be a Codec, but a Codec may not necessarily
+ * be able to be an ImageDecoder.
+ *
+ * Used in image:
+ *  - BitmapDecoder
+ *  - PICTDecoder
+ *
+ * Used in video:
+ *  - AVIDecoder
+ *  - QuickTimeDecoder
+ *  - VMDDecoder
+ */
+class Codec {
+public:
+	Codec() {}
+	virtual ~Codec() {}
+
+	/**
+	 * A type of dithering.
+	 */
+	enum DitherType {
+		/** Unknown */
+		kDitherTypeUnknown,
+
+		/** Video for Windows dithering */
+		kDitherTypeVFW,
+
+		/** QuickTime dithering */
+		kDitherTypeQT
+	};
+
+	/**
+	 * Decode the frame for the given data and return a pointer to a surface
+	 * containing the decoded frame.
+	 *
+	 * @return a pointer to the decoded frame
+	 */
+	virtual const Graphics::Surface *decodeFrame(Common::SeekableReadStream &stream) = 0;
+
+	/**
+	 * Get the format that the surface returned from decodeImage() will
+	 * be in.
+	 */
+	virtual Graphics::PixelFormat getPixelFormat() const = 0;
+
+	/**
+	 * Select the preferred format to use, for codecs where this is faster than converting
+	 * the image afterwards. Returns true if supported, and false otherwise.
+	 */
+	virtual bool setOutputPixelFormat(const Graphics::PixelFormat &format) { return format == getPixelFormat(); }
+
+	/**
+	 * Can this codec's frames contain a palette?
+	 */
+	virtual bool containsPalette() const { return false; }
+
+	/**
+	 * Get the palette last decoded from decodeImage
+	 */
+	virtual const byte *getPalette() { return 0; }
+
+	/**
+	 * Does the codec have a dirty palette?
+	 */
+	virtual bool hasDirtyPalette() const { return false; }
+
+	/**
+	 * Can the codec dither down to 8bpp?
+	 */
+	virtual bool canDither(DitherType type) const { return false; }
+
+	/**
+	 * Activate dithering mode with a palette
+	 */
+	virtual void setDither(DitherType type, const byte *palette) {}
+
+	/**
+	 * Set the decoding accuracy of the codec, if supported
+	 */
+	virtual void setCodecAccuracy(CodecAccuracy accuracy) {}
+
+	/**
+	 * Get the preferred default pixel format for use with YUV codecs
+	 */
+	static Graphics::PixelFormat getDefaultYUVFormat();
+};
+
+/**
+ * Create a codec given a bitmap/AVI compression tag and stream handler tag (can be 0)
+ */
+Codec *createBitmapCodec(uint32 tag, uint32 streamTag, int width, int height, int bitsPerPixel);
+
+/**
+ * Create a codec given a QuickTime compression tag.
+ */
+Codec *createQuickTimeCodec(uint32 tag, int width, int height, int bitsPerPixel);
+
+} // End of namespace Image
+
+#endif