Scanline decoding for bmp

src/codec/SkSwizzler.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 SkSwizzler_DEFINED
 #define SkSwizzler_DEFINED
 
@@ skipping 170 matching lines @@
      */
     ResultAlpha swizzle(void* dst, const uint8_t* SK_RESTRICT src);
 
 private:
 
     /**
      *  Method for converting raw data to Skia pixels.
      *  @param dstRow Row in which to write the resulting pixels.
      *  @param src Row of src data, in format specified by SrcConfig
      *  @param dstWidth Width in pixels of the destination
-     *  @param deltaSrc if bitsPerPixel % 8 == 0, deltaSrc is bytesPerPixel
-     *                  else, deltaSrc is bitsPerPixel
+     *  @param bpp if bitsPerPixel % 8 == 0, deltaSrc is bytesPerPixel
+     *             else, deltaSrc is bitsPerPixel
+     *  @param deltaSrc bpp * sampleX

[scroggo, 2015/08/26 22:40:09]

It seems a little weird to me that these two parameters are not independent. On
the other hand, I do not see a better way of passing along the required info.

[msarett, 2015/08/27 15:00:27]

I agree that it it strange - but I think this is better than passing sampleX and
performing the multiplication each time the rowProc is called.

[scroggo, 2015/08/27 20:14:22]

Agreed.

      *  @param ctable Colors (used for kIndex source).
      *  @param offset The offset before the first pixel to sample.
                         Is in bytes or bits based on what deltaSrc is in.
      */
     typedef ResultAlpha (*RowProc)(void* SK_RESTRICT dstRow,
                                    const uint8_t* SK_RESTRICT src,
-                                   int dstWidth, int deltaSrc, int offset,
+                                   int dstWidth, int bpp, int deltaSrc, int offset,
                                    const SkPMColor ctable[]);
 
     const RowProc       fRowProc;
     const SkPMColor*    fColorTable;      // Unowned pointer
     const int           fDeltaSrc;        // if bitsPerPixel % 8 == 0
                                           //     deltaSrc is bytesPerPixel
                                           // else
                                           //     deltaSrc is bitsPerPixel
     const SkImageInfo   fDstInfo;
     int                 fCurrY;
     const int           fX0;              // first X coord to sample
     const int           fSampleX;         // step between X samples
 
     SkSwizzler(RowProc proc, const SkPMColor* ctable, int deltaSrc, const SkImageInfo& info, 
                int sampleX);
 };
 #endif // SkSwizzler_DEFINED