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26 #ifndef GIFImageDecoder_h
27 #define GIFImageDecoder_h
29 #include "ImageDecoder.h"
30 #include <wtf/OwnPtr.h>
32 struct GIFImageReader;
36 // This class decodes the GIF image format.
37 class GIFImageDecoder : public ImageDecoder {
39 GIFImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption);
40 virtual ~GIFImageDecoder();
42 enum GIFQuery { GIFFullQuery, GIFSizeQuery, GIFFrameCountQuery };
45 virtual String filenameExtension() const { return "gif"; }
46 virtual void setData(SharedBuffer* data, bool allDataReceived);
47 virtual bool isSizeAvailable();
48 virtual bool setSize(unsigned width, unsigned height);
49 virtual size_t frameCount();
50 virtual int repetitionCount() const;
51 virtual ImageFrame* frameBufferAtIndex(size_t index);
52 // CAUTION: setFailed() deletes |m_reader|. Be careful to avoid
53 // accessing deleted memory, especially when calling this from inside
55 virtual bool setFailed();
56 virtual void clearFrameBufferCache(size_t clearBeforeFrame);
58 // Callbacks from the GIF reader.
59 void decodingHalted(unsigned bytesLeft);
60 bool haveDecodedRow(unsigned frameIndex, unsigned char* rowBuffer, unsigned char* rowEnd, unsigned rowNumber, unsigned repeatCount, bool writeTransparentPixels);
61 bool frameComplete(unsigned frameIndex, unsigned frameDuration, ImageFrame::FrameDisposalMethod disposalMethod);
65 // If the query is GIFFullQuery, decodes the image up to (but not
66 // including) |haltAtFrame|. Otherwise, decodes as much as is needed to
67 // answer the query, ignoring bitmap data. If decoding fails but there
68 // is no more data coming, sets the "decode failure" flag.
69 void decode(unsigned haltAtFrame, GIFQuery);
71 // Called to initialize the frame buffer with the given index, based on
72 // the previous frame's disposal method. Returns true on success. On
73 // failure, this will mark the image as failed.
74 bool initFrameBuffer(unsigned frameIndex);
76 bool m_alreadyScannedThisDataForFrameCount;
77 bool m_currentBufferSawAlpha;
78 mutable int m_repetitionCount;
79 OwnPtr<GIFImageReader> m_reader;
80 unsigned m_readOffset;
83 } // namespace WebCore