image/decoders/nsWebPDecoder.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef mozilla_image_decoders_nsWebPDecoder_h
   8 #define mozilla_image_decoders_nsWebPDecoder_h
   9
  10 #include "Decoder.h"
  11 #include "webp/demux.h"
  12 #include "StreamingLexer.h"
  13 #include "SurfacePipe.h"
  14
  15 namespace mozilla {
  16 namespace image {
  17 class RasterImage;
  18
  19 class nsWebPDecoder final : public Decoder {
  20  public:
  21   virtual ~nsWebPDecoder();
  22
  23   DecoderType GetType() const override { return DecoderType::WEBP; }
  24
  25  protected:
  26   LexerResult DoDecode(SourceBufferIterator& aIterator,
  27                        IResumable* aOnResume) override;
  28   Maybe<Telemetry::HistogramID> SpeedHistogram() const override;
  29
  30  private:
  31   friend class DecoderFactory;
  32
  33   // Decoders should only be instantiated via DecoderFactory.
  34   explicit nsWebPDecoder(RasterImage* aImage);
  35
  36   void ApplyColorProfile(const char* aProfile, size_t aLength);
  37
  38   LexerResult UpdateBuffer(SourceBufferIterator& aIterator,
  39                            SourceBufferIterator::State aState);
  40   LexerResult ReadData();
  41   LexerResult ReadHeader(WebPDemuxer* aDemuxer, bool aIsComplete);
  42   LexerResult ReadPayload(WebPDemuxer* aDemuxer, bool aIsComplete);
  43
  44   nsresult CreateFrame(const OrientedIntRect& aFrameRect);
  45   void EndFrame();
  46
  47   LexerResult ReadSingle(const uint8_t* aData, size_t aLength,
  48                          const OrientedIntRect& aFrameRect);
  49
  50   LexerResult ReadMultiple(WebPDemuxer* aDemuxer, bool aIsComplete);
  51
  52   /// The SurfacePipe used to write to the output surface.
  53   SurfacePipe mPipe;
  54
  55   /// The buffer used to accumulate data until the complete WebP header is
  56   /// received, if and only if the iterator is discontiguous.
  57   Vector<uint8_t> mBufferedData;
  58
  59   /// The libwebp output buffer descriptor pointing to the decoded data.
  60   WebPDecBuffer mBuffer;
  61
  62   /// The libwebp incremental decoder descriptor, wraps mBuffer.
  63   WebPIDecoder* mDecoder;
  64
  65   /// Blend method for the current frame.
  66   BlendMethod mBlend;
  67
  68   /// Disposal method for the current frame.
  69   DisposalMethod mDisposal;
  70
  71   /// Frame timeout for the current frame;
  72   FrameTimeout mTimeout;
  73
  74   /// Surface format for the current frame.
  75   gfx::SurfaceFormat mFormat;
  76
  77   /// Frame rect for the current frame.
  78   OrientedIntRect mFrameRect;
  79
  80   /// The last row of decoded pixels written to mPipe.
  81   int mLastRow;
  82
  83   /// Number of decoded frames.
  84   uint32_t mCurrentFrame;
  85
  86   /// Pointer to the start of the contiguous encoded image data.
  87   const uint8_t* mData;
  88
  89   /// Length of data pointed to by mData.
  90   size_t mLength;
  91
  92   /// True if the iterator has reached its end.
  93   bool mIteratorComplete;
  94
  95   /// True if this decoding pass requires a WebPDemuxer.
  96   bool mNeedDemuxer;
  97
  98   /// True if we have setup the color profile for the image.
  99   bool mGotColorProfile;
 100 };
 101
 102 }  // namespace image
 103 }  // namespace mozilla
 104
 105 #endif  // mozilla_image_decoders_nsWebPDecoder_h