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      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef RASTERMILL_FRAMESQUENCE_WEBP_H
     18 #define RASTERMILL_FRAMESQUENCE_WEBP_H
     19 
     20 #include "config.h"
     21 #include "webp/decode.h"
     22 #include "webp/demux.h"
     23 
     24 #include "Stream.h"
     25 #include "Color.h"
     26 #include "FrameSequence.h"
     27 
     28 // Parser for a possibly-animated WebP bitstream.
     29 class FrameSequence_webp : public FrameSequence {
     30 public:
     31     FrameSequence_webp(Stream* stream);
     32     virtual ~FrameSequence_webp();
     33 
     34     virtual int getWidth() const {
     35         return WebPDemuxGetI(mDemux, WEBP_FF_CANVAS_WIDTH);
     36     }
     37 
     38     virtual int getHeight() const {
     39         return WebPDemuxGetI(mDemux, WEBP_FF_CANVAS_HEIGHT);
     40     }
     41 
     42     virtual bool isOpaque() const {
     43         return !(mFormatFlags & ALPHA_FLAG);
     44     }
     45 
     46     virtual int getFrameCount() const {
     47         return WebPDemuxGetI(mDemux, WEBP_FF_FRAME_COUNT);
     48     }
     49 
     50     virtual int getDefaultLoopCount() const {
     51         return mLoopCount;
     52     }
     53 
     54     virtual FrameSequenceState* createState() const;
     55 
     56     WebPDemuxer* getDemuxer() const { return mDemux; }
     57 
     58     bool isKeyFrame(size_t frameNr) const { return mIsKeyFrame[frameNr]; }
     59 
     60 private:
     61     void constructDependencyChain();
     62 
     63     WebPData mData;
     64     WebPDemuxer* mDemux;
     65     int mLoopCount;
     66     uint32_t mFormatFlags;
     67     // mIsKeyFrame[i] is true if ith canvas can be constructed without decoding any prior frames.
     68     bool* mIsKeyFrame;
     69 };
     70 
     71 // Produces frames of a possibly-animated WebP file for display.
     72 class FrameSequenceState_webp : public FrameSequenceState {
     73 public:
     74     FrameSequenceState_webp(const FrameSequence_webp& frameSequence);
     75     virtual ~FrameSequenceState_webp();
     76 
     77     // Returns frame's delay time in milliseconds.
     78     virtual long drawFrame(int frameNr,
     79             Color8888* outputPtr, int outputPixelStride, int previousFrameNr);
     80 
     81 private:
     82     void initializeFrame(const WebPIterator& currIter, Color8888* currBuffer, int currStride,
     83             const WebPIterator& prevIter, const Color8888* prevBuffer, int prevStride);
     84     bool decodeFrame(const WebPIterator& iter, Color8888* currBuffer, int currStride,
     85             const WebPIterator& prevIter, const Color8888* prevBuffer, int prevStride);
     86 
     87     const FrameSequence_webp& mFrameSequence;
     88     WebPDecoderConfig mDecoderConfig;
     89     Color8888* mPreservedBuffer;
     90 };
     91 
     92 #endif //RASTERMILL_FRAMESQUENCE_WEBP_H
     93