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 "ImageDecoder.h" 30 #include <wtf/OwnPtr.h> 31 32 struct 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 GIFQuery { GIFFullQuery, GIFSizeQuery, GIFFrameCountQuery }; 43 44 // ImageDecoder 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 54 // GIFImageReader! 55 virtual bool setFailed(); 56 virtual void clearFrameBufferCache(size_t clearBeforeFrame); 57 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); 62 void gifComplete(); 63 64 private: 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); 70 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); 75 76 bool m_alreadyScannedThisDataForFrameCount; 77 bool m_currentBufferSawAlpha; 78 mutable int m_repetitionCount; 79 OwnPtr<GIFImageReader> m_reader; 80 unsigned m_readOffset; 81 }; 82 83 } // namespace WebCore 84 85 #endif 86
