Refactor SkBitmapRegionDecoderInterface for Android

tools/SkBitmapRegionDecoderInterface.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.
  */
 
 #ifndef SkBitmapRegionDecoder_DEFINED
 #define SkBitmapRegionDecoder_DEFINED
 
@@ skipping 17 matching lines @@
      * @param data     Refs the data while this object exists, unrefs on destruction
      * @param strategy Strategy used for scaling and subsetting
      * @return         Tries to create an SkBitmapRegionDecoder, returns NULL on failure
      */
     static SkBitmapRegionDecoderInterface* CreateBitmapRegionDecoder(
             SkData* data, Strategy strategy);
 
     /*
      * Decode a scaled region of the encoded image stream
      *
-     * @param start_x    X-coordinate of upper-left corner of region.
-     *                   This coordinate is unscaled, relative to the original dimensions.
-     * @param start_y    Y-coordinate of upper-left corner of region.
-     *                   This coordinate is unscaled, relative to the original dimensions.
-     * @param width      Width of the region to decode.
-     *                   This distance is unscaled, relative to the original dimensions.
-     * @param height     Height of the region to decode.
-     *                   This distance is unscaled, relative to the original dimensions.
-     * @param sampleSize An integer downscaling factor for the decode.
-     * @param colorType  Preferred output colorType.
-     *                   New implementations should return NULL if they do not support
-     *                   decoding to this color type.
-     *                   The old kOriginal_Strategy will decode to a default color type
-     *                   if this color type is unsupported.
-     * @return           Pointer to a bitmap of the decoded region on success, NULL on
-     *                   failure.
+     * @param bitmap          Container for decoded pixels.  It is assumed that the pixels
+     *                        are initially unallocated and will be allocated by this function.
+     * @param allocator       Allocator for the pixels.  If this is NULL, the default
+     *                        allocator (HeapAllocator) will be used.
+     * @param desiredSubset   Subset of the original image to decode.
+     * @param sampleSize      An integer downscaling factor for the decode.
+     * @param colorType       Preferred output colorType.
+     *                        New implementations should return NULL if they do not support
+     *                        decoding to this color type.
+     *                        The old kOriginal_Strategy will decode to a default color type
+     *                        if this color type is unsupported.
+     * @param requireUnpremul If the image is not opaque, we will use this to determine the
+     *                        alpha type to use.
+     *
      */
-    virtual SkBitmap* decodeRegion(int start_x, int start_y, int width,
-                                   int height, int sampleSize,
-                                   SkColorType colorType) = 0;
+    virtual bool decodeRegion(SkBitmap* bitmap, SkBitmap::Allocator* allocator,
+                              const SkIRect& desiredSubset, int sampleSize,
+                              SkColorType colorType, bool requireUnpremul) = 0;
     /*
      * @param  Requested destination color type
      * @return true if we support the requested color type and false otherwise
      */
     virtual bool conversionSupported(SkColorType colorType) = 0;
 
     int width() const { return fWidth; }
     int height() const { return fHeight; }
 
     virtual ~SkBitmapRegionDecoderInterface() {}
 
 protected:
 
     SkBitmapRegionDecoderInterface(int width, int height)
         : fWidth(width)
         , fHeight(height)
     {}
 
 private:
     const int fWidth;
     const int fHeight;
 };
 
 #endif