SkScaledCodec class

src/codec/SkSwizzler.h

Index: src/codec/SkSwizzler.h
diff --git a/src/codec/SkSwizzler.h b/src/codec/SkSwizzler.h
index b00ee14e0699189f9834ccc7624ef8ee8924c0f8..5c0d73da512771aa04623d026b23c670c7f070c8 100644
--- a/src/codec/SkSwizzler.h
+++ b/src/codec/SkSwizzler.h
@@ -122,12 +122,13 @@ public:
      *  @param ZeroInitialized Whether dst is zero-initialized. The
                                implementation may choose to skip writing zeroes
      *                         if set to kYes_ZeroInitialized.
+     *  @param sampleX the step between samples in the x direction.

[scroggo, 2015/07/28 15:58:10]

As stated elsewhere, I think we should consider combining this with
ZeroInitialized, and just pass the Options object.

[emmaleer, 2015/07/29 21:55:08]

SampleX is no longer needed to be stored in the options object, so I left this
as is.

      *  @return A new SkSwizzler or NULL on failure.
      */
     static SkSwizzler* CreateSwizzler(SrcConfig, const SkPMColor* ctable,
                                       const SkImageInfo&, void* dst,
                                       size_t dstRowBytes,
-                                      SkCodec::ZeroInitialized);
+                                      SkCodec::ZeroInitialized, int sampleX);
 
     /**
      * Fill the remainder of the destination with a single color
@@ -245,9 +246,11 @@ private:
     void*               fDstRow;
     const size_t        fDstRowBytes;
     int                 fCurrY;
+    int                 fX0;              // first X coord to sample
+    int                 fSampleX;         // step between X samples

[scroggo, 2015/07/28 15:58:10]

This can now be const.

fX0 can also be const, if you initialize it in the intializer list like so:

fX0(sampleX == 1 ? 0 : sampleX >> 1)

On a related note, I thought we needed to check to make sure the sample size was
not too big. Do we do that elsewhere?

[emmaleer, 2015/07/29 21:55:08]

SampleX is set to srcWidth / dstWidth in initializeSwizzler, so will never be
too big

 
     SkSwizzler(RowProc proc, const SkPMColor* ctable, int deltaSrc,
-               const SkImageInfo& info, void* dst, size_t rowBytes);
+               const SkImageInfo& info, void* dst, size_t rowBytes, int sampleX);
 
 };
 #endif // SkSwizzler_DEFINED