diff options
| -rw-r--r-- | vcl/source/bitmap/bitmapscalesuper.cxx | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/vcl/source/bitmap/bitmapscalesuper.cxx b/vcl/source/bitmap/bitmapscalesuper.cxx index cbfb08e330b6..206054f10939 100644 --- a/vcl/source/bitmap/bitmapscalesuper.cxx +++ b/vcl/source/bitmap/bitmapscalesuper.cxx @@ -24,6 +24,16 @@ #define MAP( cVal0, cVal1, nFrac ) ((sal_uInt8)((((long)(cVal0)<<7L)+nFrac*((long)(cVal1)-(cVal0)))>>7L)) +/** + * generate a map of pixel source locations and errors for each + * destination pixel; we should end up with pMapIX containing a + * series of effectively integer pixel offsets across the row eg. + * for something slightly larger than a doubling in size with + * no flips: + * pMapIX: 0 0 1 1 1 2 2 3 3 3 ... + * then pMapFX - contains fixed-point offsets from these + * co-ordinates to reflect sub-pixel positions. + */ void generateMap(long nW, long nDstW, bool bHMirr, long* pMapIX, long* pMapFX) { const double fRevScaleX = (nDstW > 1L) ? (double) (nW - 1) / (nDstW - 1) : 0.0; |