Add support for multiple frames in SkCodec

src/codec/SkGifCodec.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
+#include "SkCodecAnimation.h"
 #include "SkColorSpace.h"
 #include "SkColorTable.h"
 #include "SkImageInfo.h"
 #include "SkSwizzler.h"
+#include "../private/SkTArray.h"
 
 struct GifFileType;
 struct SavedImage;
 
 /*
  *
  * This class implements the decoding for gif images
  *
  */
 class SkGifCodec : public SkCodec {
@@ skipping 34 matching lines @@
     /*
      * Performs the full gif decode
      */
     Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&,
             SkPMColor*, int*, int*) override;
 
     SkEncodedFormat onGetEncodedFormat() const override {
         return kGIF_SkEncodedFormat;
     }
 
-    bool onRewind() override;
-
     uint64_t onGetFillValue(const SkImageInfo&) const override;
 
-    int onOutputScanline(int inputScanline) const override;
+    size_t onGetFrameCount() override {
+        return (size_t) fFrameInfos.count();
+    }
 
+    size_t onGetRequiredFrame(size_t) override;
+
+    size_t onGetFrameDuration(size_t) override;
 private:
 
-    /*
-     * A gif can contain multiple image frames.  We will only decode the first
-     * frame.  This function reads up to the first image frame, processing
-     * transparency and/or animation information that comes before the image
-     * data.
-     *
-     * @param gif        Pointer to the library type that manages the gif decode
-     * @param transIndex This call will set the transparent index based on the
-     *                   extension data.
-     */
-     static Result ReadUpToFirstImage(GifFileType* gif, uint32_t* transIndex);
-
      /*
       * A gif may contain many image frames, all of different sizes.
       * This function checks if the gif dimensions are valid, based on the frame
       * dimensions, and corrects the gif dimensions if necessary.
       *
       * @param gif       Pointer to the library type that manages the gif decode
       * @param size      Size of the image that we will decode.
       *                  Will be set by this function if the return value is true.
-      * @param frameRect Contains the dimenions and offset of the first image frame.
-      *                  Will be set by this function if the return value is true.
       *
       * @return true on success, false otherwise
       */
-     static bool GetDimensions(GifFileType* gif, SkISize* size, SkIRect* frameRect);
+     static bool GetDimensions(GifFileType* gif, SkISize* size);
 
     /*
      * Initializes the color table that we will use for decoding.
      *
      * @param dstInfo         Contains the requested dst color type.
      * @param inputColorPtr   Copies the encoded color table to the client's
      *                        input color table if the client requests kIndex8.
      * @param inputColorCount If the client requests kIndex8, sets
      *                        inputColorCount to 256.  Since gifs always
      *                        contain 8-bit indices, we need a 256 entry color
      *                        table to ensure that indexing is always in
      *                        bounds.
      */
     void initializeColorTable(const SkImageInfo& dstInfo, SkPMColor* colorPtr,
             int* inputColorCount);
 
    /*
     * Checks for invalid inputs and calls setFrameDimensions(), and
     * initializeColorTable() in the proper sequence.
     */
     Result prepareToDecode(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr,
             int* inputColorCount, const Options& opts);
 
     /*
-     * Initializes the swizzler.
+     * Recursive function to decode a frame.
      *
-     * @param dstInfo  Output image information.  Dimensions may have been
-     *                 adjusted if the image frame size does not match the size
-     *                 indicated in the header.
-     * @param options  Informs the swizzler if destination memory is zero initialized.
-     *                 Contains subset information.
+     * If !opts.fHasPriorFrame, and the frame is not independent, it will first
+     * decode the frame that it depends on.
      */
-    void initializeSwizzler(const SkImageInfo& dstInfo,
-            const Options& options);
+    void decodeFrame(const SkImageInfo& dstInfo, void* pixels, size_t dstRowBytes,
+                     const Options& opts);
 
-    SkSampler* getSampler(bool createIfNecessary) override {
-        SkASSERT(fSwizzler);
-        return fSwizzler;
-    }
-
-    /*
-     * @return true if the read is successful and false if the read fails.
-     */
-    bool readRow();
-
-    Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& opts,
-                   SkPMColor inputColorPtr[], int* inputColorCount) override;
-
-    int onGetScanlines(void* dst, int count, size_t rowBytes) override;
-
-    bool onSkipScanlines(int count) override;
-
-    /*
-     * For a scanline decode of "count" lines, this function indicates how
-     * many of the "count" lines should be skipped until we reach the top of
-     * the image frame and how many of the "count" lines are actually inside
-     * the image frame.
-     *
-     * @param count           The number of scanlines requested.
-     * @param rowsBeforeFrame Output variable.  The number of lines before
-     *                        we reach the top of the image frame.
-     * @param rowsInFrame     Output variable.  The number of lines to decode
-     *                        inside the image frame.
-     */
-    void handleScanlineFrame(int count, int* rowsBeforeFrame, int* rowsInFrame);
-
-    SkScanlineOrder onGetScanlineOrder() const override;
+    // FIXME: Old patch deletes this. Was that really necessary?
+    // void initializeSwizzler(const SkImageInfo& dstInfo,
+    //         const Options& options);
 
     /*
      * This function cleans up the gif object after the decode completes
      * It is used in a SkAutoTCallIProc template
      */
     static void CloseGif(GifFileType* gif);
 
     /*
      * Frees any extension data used in the decode
      * Used in a SkAutoTCallVProc
      */
     static void FreeExtension(SavedImage* image);
 
     /*
      * Creates an instance of the decoder
      * Called only by NewFromStream
      *
      * @param info contains properties of the encoded data
      * @param stream the stream of image data
      * @param gif pointer to library type that manages gif decode
      *            takes ownership
      * @param transIndex  The transparent index.  An invalid value
      *            indicates that there is no transparent index.
      */
     SkGifCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream,
-            GifFileType* gif, uint32_t transIndex, const SkIRect& frameRect, bool frameIsSubset);
+            GifFileType* gif, uint32_t transIndex);
+
+
+    struct FrameInfo : public SkCodecAnimation::FrameInfo {
+        uint32_t fTransIndex;
+    };
 
     SkAutoTCallVProc<GifFileType, CloseGif> fGif; // owned
     SkAutoTDeleteArray<uint8_t>             fSrcBuffer;
-    const SkIRect                           fFrameRect;
-    const uint32_t                          fTransIndex;
     uint32_t                                fFillIndex;
-    const bool                              fFrameIsSubset;
     SkAutoTDelete<SkSwizzler>               fSwizzler;
     SkAutoTUnref<SkColorTable>              fColorTable;
+    SkTArray<FrameInfo>                     fFrameInfos;
 
     typedef SkCodec INHERITED;
 };