1 /* 2 * Copyright (C) 2006 Apple Computer, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef GIFImageDecoder_h 27 #define GIFImageDecoder_h 28 29 #include "core/platform/image-decoders/ImageDecoder.h" 30 #include "wtf/OwnPtr.h" 31 32 class GIFImageReader; 33 34 namespace WebCore { 35 36 // This class decodes the GIF image format. 37 class GIFImageDecoder : public ImageDecoder { 38 public: 39 GIFImageDecoder(ImageSource::AlphaOption, ImageSource::GammaAndColorProfileOption); 40 virtual ~GIFImageDecoder(); 41 42 enum GIFParseQuery { GIFSizeQuery, GIFFrameCountQuery }; 43 44 // ImageDecoder 45 virtual String filenameExtension() const OVERRIDE { return "gif"; } 46 virtual void setData(SharedBuffer* data, bool allDataReceived) OVERRIDE; 47 virtual bool isSizeAvailable() OVERRIDE; 48 virtual size_t frameCount() OVERRIDE; 49 virtual int repetitionCount() const OVERRIDE; 50 virtual ImageFrame* frameBufferAtIndex(size_t) OVERRIDE; 51 virtual bool frameIsCompleteAtIndex(size_t) const OVERRIDE; 52 virtual float frameDurationAtIndex(size_t) const OVERRIDE; 53 virtual size_t clearCacheExceptFrame(size_t) OVERRIDE; 54 // CAUTION: setFailed() deletes |m_reader|. Be careful to avoid 55 // accessing deleted memory, especially when calling this from inside 56 // GIFImageReader! 57 virtual bool setFailed() OVERRIDE; 58 59 // Callbacks from the GIF reader. 60 bool haveDecodedRow(size_t frameIndex, const Vector<unsigned char>& rowBuffer, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels); 61 bool frameComplete(size_t frameIndex); 62 63 // For testing. 64 bool parseCompleted() const; 65 66 private: 67 virtual void clearFrameBuffer(size_t frameIndex) OVERRIDE; 68 69 // Parses as much as is needed to answer the query, ignoring bitmap 70 // data. If parsing fails, sets the "decode failure" flag. 71 void parse(GIFParseQuery); 72 73 // Decodes bitmap data of the frame. Depending on the disposal method 74 // of prior frames, also decodes all required prior frames. If decoding 75 // fails, sets the "decode failure" flag. 76 void decode(size_t frameIndex); 77 78 // Called to initialize the frame buffer with the given index, based on 79 // the previous frame's disposal method. Returns true on success. On 80 // failure, this will mark the image as failed. 81 bool initFrameBuffer(size_t frameIndex); 82 83 bool m_currentBufferSawAlpha; 84 mutable int m_repetitionCount; 85 OwnPtr<GIFImageReader> m_reader; 86 }; 87 88 } // namespace WebCore 89 90 #endif 91
