SkScaledCodec class

src/codec/SkJpegCodec.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 SkJpegCodec_DEFINED
 #define SkJpegCodec_DEFINED
 
@@ skipping 41 matching lines @@
     Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
             SkPMColor*, int*) override;
 
     SkEncodedFormat onGetEncodedFormat() const override {
         return kJPEG_SkEncodedFormat;
     }
 
     SkScanlineDecoder* onGetScanlineDecoder(const SkImageInfo& dstInfo, const Options& options,
             SkPMColor ctable[], int* ctableCount) override;
 
+    /*
+     * Checks if we can patially natively scale to the desiredScale, and partially natively scales 
+     * the dimensions if possible.
+     * Returns the new sampleSize, which is used to finish scaling to the desiredScale
+     * Ex: desiredScale = 1/6. Natively can scale by 1/2. New sampleSize = 3, as there is still 
+     * 1/3 scaling left to do, which is done by sampling. 
+     * Returns -1 if partial native scaling is not supported.
+     */
+    int onPartiallyNativelyScale(float desiredScale) override; 
+
 private:
+    SkAutoTDelete<SkSwizzler>   fSwizzler;
 
     /*
      * Read enough of the stream to initialize the SkJpegCodec.
      * Returns a bool representing success or failure.
      *
      * @param codecOut
      * If this returns true, and codecOut was not NULL,
      * codecOut will be set to a new SkJpegCodec.
      *
      * @param decoderMgrOut
@@ skipping 14 matching lines @@
      * Creates an instance of the decoder
      * Called only by NewFromStream
      *
      * @param srcInfo contains the source width and height
      * @param stream the encoded image data
      * @param decoderMgr holds decompress struct, src manager, and error manager
      *                   takes ownership
      */
     SkJpegCodec(const SkImageInfo& srcInfo, SkStream* stream, JpegDecoderMgr* decoderMgr);
 
+    // Helper to set up swizzler.
+    Result initializeSwizzler(const SkImageInfo& requestedInfo, void* dst,
+                              size_t rowBytes, const Options&, SkPMColor*, 
+                              int* ctableCount, int dstWidth);
+
     /*
      * Handles rewinding the input stream if it is necessary
      */
     bool handleRewind();
 
     /*
      * Checks if the conversion between the input image and the requested output
      * image has been implemented
      * Sets the output color space
      */
     bool setOutputColorSpace(const SkImageInfo& dst);
 
     /*
-     * Checks if we can scale to the requested dimensions and scales the dimensions
-     * if possible
+     * Checks if we can natively scale to the requested dimensions and natively scales the 
+     * dimensions if possible
      */
-    bool scaleToDimensions(uint32_t width, uint32_t height);
+    bool nativelyScaleToDimensions(uint32_t width, uint32_t height); 
 
     /*
      * Create the swizzler based on the encoded format
      */
     void initializeSwizzler(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes,
             const Options& options);
 
     SkAutoTDelete<JpegDecoderMgr> fDecoderMgr;
-
+    int                           fPartialDenom;
+    int                           fPartialNum;
     friend class SkJpegScanlineDecoder;
 
     typedef SkCodec INHERITED;
 };
 
 #endif