Expand filter 0 to handle transparent drawBitmapRect paints
https://codereview.chromium.org/13394014/
git-svn-id: http://skia.googlecode.com/svn/trunk@8486 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/filtermain.cpp b/tools/filtermain.cpp
index 216fa66..cbebb49 100644
--- a/tools/filtermain.cpp
+++ b/tools/filtermain.cpp
@@ -61,18 +61,15 @@
SkPaint* dbmrPaint = dbmr->paint();
// For this optimization we only fold the saveLayer and drawBitmapRect
- // together if the saveLayer's draw is simple (i.e., no fancy effects) and
- // and the only difference in the colors is that the saveLayer's can have
- // an alpha while the drawBitmapRect's is opaque.
- // TODO: it should be possible to fold them together even if they both
- // have different non-255 alphas but this is low priority since we have
- // never seen that case
- // If either operation lacks a paint then the collapse is trivial
+ // together if the saveLayer's draw is simple (i.e., no fancy effects)
+ // and the only difference in the colors is their alpha value
SkColor layerColor = saveLayerPaint->getColor() | 0xFF000000; // force opaque
+ SkColor dbmrColor = dbmrPaint->getColor() | 0xFF000000; // force opaque
+ // If either operation lacks a paint then the collapse is trivial
return NULL == saveLayerPaint ||
NULL == dbmrPaint ||
- (is_simple(*saveLayerPaint) && dbmrPaint->getColor() == layerColor);
+ (is_simple(*saveLayerPaint) && dbmrColor == layerColor);
}
// Fold the saveLayer's alpha into the drawBitmapRect and remove the saveLayer
@@ -90,8 +87,17 @@
// if the DBMR doesn't have a paint just use the saveLayer's
dbmr->setPaint(*saveLayerPaint);
} else if (NULL != saveLayerPaint) {
- SkColor newColor = SkColorSetA(dbmrPaint->getColor(),
- SkColorGetA(saveLayerPaint->getColor()));
+ // Both paints are present so their alphas need to be combined
+ SkColor color = saveLayerPaint->getColor();
+ int a0 = SkColorGetA(color);
+
+ color = dbmrPaint->getColor();
+ int a1 = SkColorGetA(color);
+
+ int newA = SkMulDiv255Round(a0, a1);
+ SkASSERT(newA <= 0xFF);
+
+ SkColor newColor = SkColorSetA(color, newA);
dbmrPaint->setColor(newColor);
}
}
@@ -457,7 +463,7 @@
a1 = 0xFF;
}
- int newA = (a0 * a1) / 255;
+ int newA = SkMulDiv255Round(a0, a1);
SkASSERT(newA <= 0xFF);
SkPaint* dbmrPaint = dbmr->paint();