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 THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_GIF_GIF_IMAGE_DECODER_H_ 27 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_IMAGE_DECODERS_GIF_GIF_IMAGE_DECODER_H_ 28 29 #include <memory> 30 31 #include "base/macros.h" 32 #include "third_party/blink/renderer/platform/image-decoders/image_decoder.h" 33 34 #include "third_party/skia/include/codec/SkCodec.h" 35 36 namespace blink { 37 38 class SegmentStream; 39 40 // This class decodes the GIF image format. 41 class PLATFORM_EXPORT GIFImageDecoder final : public ImageDecoder { 42 public: 43 GIFImageDecoder(AlphaOption, const ColorBehavior&, size_t max_decoded_bytes); 44 ~GIFImageDecoder() override; 45 46 // ImageDecoder: FilenameExtension()47 String FilenameExtension() const override { return "gif"; } 48 void OnSetData(SegmentReader* data) override; 49 int RepetitionCount() const override; 50 bool FrameIsReceivedAtIndex(size_t) const override; 51 base::TimeDelta FrameDurationAtIndex(size_t) const override; 52 // CAUTION: SetFailed() deletes |codec_|. Be careful to avoid 53 // accessing deleted memory. 54 bool SetFailed() override; 55 56 size_t ClearCacheExceptFrame(size_t) override; 57 58 private: 59 // ImageDecoder: DecodeSize()60 void DecodeSize() override {} 61 size_t DecodeFrameCount() override; 62 void InitializeNewFrame(size_t) override; 63 void Decode(size_t) override; 64 // When the disposal method of the frame is DisposeOverWritePrevious, the 65 // next frame will use a previous frame's buffer as its starting state, so 66 // we can't take over the data in that case. Before calling this method, the 67 // caller must verify that the frame exists. 68 bool CanReusePreviousFrameBuffer(size_t) const override; 69 70 // When a frame depends on a previous frame's content, there is a list of 71 // candidate reference frames. This function will find a previous frame from 72 // that list which satisfies the requirements of being a reference frame 73 // (kFrameComplete, not kDisposeOverwritePrevious). 74 // If no frame is found, it returns kNotFound. 75 size_t GetViableReferenceFrameIndex(size_t) const; 76 77 std::unique_ptr<SkCodec> codec_; 78 // |codec_| owns the SegmentStream, but we need access to it to append more 79 // data as it arrives. 80 SegmentStream* segment_stream_ = nullptr; 81 mutable int repetition_count_ = kAnimationLoopOnce; 82 int prior_frame_ = SkCodec::kNoFrame; 83 84 DISALLOW_COPY_AND_ASSIGN(GIFImageDecoder); 85 }; 86 87 } // namespace blink 88 89 #endif 90