Optimize highQualityFilter

src/core/SkBitmapFilter.cpp

Index: src/core/SkBitmapFilter.cpp
diff --git a/src/core/SkBitmapFilter.cpp b/src/core/SkBitmapFilter.cpp
index 20a05142506c1890e2c4eea964299def656da068..fce4c1d5fbc2f1c9b913e89515bea1481c33e013 100644
--- a/src/core/SkBitmapFilter.cpp
+++ b/src/core/SkBitmapFilter.cpp
@@ -29,6 +29,7 @@ void highQualityFilter(ColorPacker pack, const SkBitmapProcState& s, int x, int
     const int maxX = s.fBitmap->width();
     const int maxY = s.fBitmap->height();
     SkAutoTMalloc<SkScalar> xWeights(maxX);
+    const SkBitmapFilter* filter = s.getBitmapFilter();
 
     while (count-- > 0) {
         SkPoint srcPt;
@@ -40,30 +41,33 @@ void highQualityFilter(ColorPacker pack, const SkBitmapProcState& s, int x, int
         SkScalar weight = 0;
         SkScalar fr = 0, fg = 0, fb = 0, fa = 0;
 
-        int y0 = SkClampMax(SkScalarCeilToInt(srcPt.fY-s.getBitmapFilter()->width()), maxY);
-        int y1 = SkClampMax(SkScalarFloorToInt(srcPt.fY+s.getBitmapFilter()->width()+1), maxY);
-        int x0 = SkClampMax(SkScalarCeilToInt(srcPt.fX-s.getBitmapFilter()->width()), maxX);
-        int x1 = SkClampMax(SkScalarFloorToInt(srcPt.fX+s.getBitmapFilter()->width())+1, maxX);
+        int y0 = SkClampMax(SkScalarCeilToInt(srcPt.fY - filter->width()), maxY);
+        int y1 = SkClampMax(SkScalarFloorToInt(srcPt.fY + filter->width() + 1), maxY);
+        int x0 = SkClampMax(SkScalarCeilToInt(srcPt.fX - filter->width()), maxX);
+        int x1 = SkClampMax(SkScalarFloorToInt(srcPt.fX + filter->width()) + 1, maxX);
 
         for (int srcX = x0; srcX < x1 ; srcX++) {
             // Looking these up once instead of each loop is a ~15% speedup.
-            xWeights[srcX - x0] = s.getBitmapFilter()->lookupScalar((srcPt.fX - srcX));
+            xWeights[srcX - x0] = filter->lookupScalar((srcPt.fX - srcX));
         }
 
         for (int srcY = y0; srcY < y1; srcY++) {
-            SkScalar yWeight = s.getBitmapFilter()->lookupScalar((srcPt.fY - srcY));
+            SkScalar yWeight = filter->lookupScalar((srcPt.fY - srcY));
 
             for (int srcX = x0; srcX < x1 ; srcX++) {
                 SkScalar xWeight = xWeights[srcX - x0];
 
                 SkScalar combined_weight = SkScalarMul(xWeight, yWeight);
+                weight += combined_weight;
 
                 SkPMColor c = *s.fBitmap->getAddr32(srcX, srcY);
+                if (!c) {
+                    continue;
+                }
                 fr += combined_weight * SkGetPackedR32(c);

[reed1, 2014/11/25 14:34:33]

boy oh boy, this seems to beg for Sk4f ...

[mtklein, 2014/11/25 15:02:22]

Yep, I will certainly try this out.

                 fg += combined_weight * SkGetPackedG32(c);
                 fb += combined_weight * SkGetPackedB32(c);
                 fa += combined_weight * SkGetPackedA32(c);
-                weight += combined_weight;
             }
         }