Fill incomplete images in SkCodec parent class

src/codec/SkMaskSwizzler.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 SkMaskSwizzler_DEFINED
 #define SkMaskSwizzler_DEFINED
 
 #include "SkMasks.h"
@@ skipping 17 matching lines @@
     static SkMaskSwizzler* CreateMaskSwizzler(const SkImageInfo& dstInfo,
                                               const SkImageInfo& srcInfo,
                                               SkMasks* masks,
                                               uint32_t bitsPerPixel);
 
     /*
      * Swizzle a row
      */
     SkSwizzler::ResultAlpha swizzle(void* dst, const uint8_t* SK_RESTRICT src);
 
+    /**
+     * Implement fill using a custom width.
+     */
+    void fill(void* dst, const SkImageInfo& info, size_t rowBytes, uint32_t colorOrIndex,

[scroggo, 2015/10/08 13:50:30]

Again, I think this parameter order should match getPixels (info, dst, rowbytes)

Also, it seems weird that this function needs to be passed so much information.
For example, it was created with a particular color type/alpha type, so it
should only use that one (although I suppose it does not store that info). I
suppose this allows it to call SkSampler::Fill and share code.

[msarett, 2015/10/08 15:33:25]

Changed the parameter order.

Yeah on the opposite extreme, the Swizzler could store colorType, alphaType,
zeroInit, and (maybe) rowBytes.  Then we would only need to pass in dst, numRow,
and colorOrIndex.

+            SkCodec::ZeroInitialized zeroInit) override {
+        const SkImageInfo fillInfo = info.makeWH(fDstWidth, info.height());
+        SkSampler::Fill(dst, fillInfo, rowBytes, colorOrIndex, zeroInit);
+    }
+
 private:
 
     /*
      * Row procedure used for swizzle
      */
     typedef SkSwizzler::ResultAlpha (*RowProc)(
             void* dstRow, const uint8_t* srcRow, int width,
             SkMasks* masks, uint32_t startX, uint32_t sampleX);
 
     /*
      * Constructor for mask swizzler
      */
     SkMaskSwizzler(int width, SkMasks* masks, RowProc proc);
 
     int onSetSampleX(int) override;
 
     SkMasks*        fMasks;           // unowned
     const RowProc   fRowProc;
 
     // FIXME: Can this class share more with SkSwizzler? These variables are all the same.
     const int       fSrcWidth;        // Width of the source - i.e. before any sampling.
     int             fDstWidth;        // Width of dst, which may differ with sampling.
     int             fSampleX;
     int             fX0;
 };
 
 #endif