commit 35c733cc9ce71c4513dfb6f39c4d9df5905e897c
author senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Tue May 28 19:43:05 2013 +0000
committer senorblanco@chromium.org <senorblanco@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Tue May 28 19:43:05 2013 +0000
tree f731e87de053fdf7d9afbc5bff6a62bc97833358
parent 435401d38606e9b5b747890da23fd46d7c464ccd

Fix alpha computation in SkArithmeticMode.

Note: this will require new baselines for the arithmode GM.

R=reed@google.com

Review URL: https://codereview.chromium.org/15917010

git-svn-id: http://skia.googlecode.com/svn/trunk@9302 2bbb7eff-a529-9590-31e7-b0007b416f81

gm/arithmode.cpp

diff --git a/gm/arithmode.cpp b/gm/arithmode.cpp
index f5e1091..2a97eca 100644
--- a/gm/arithmode.cpp
+++ b/gm/arithmode.cpp
@@ -29,8 +29,8 @@
     SkPaint paint;
     SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} };
     SkColor colors[] = {
-        SK_ColorBLACK, SK_ColorGREEN, SK_ColorCYAN,
-        SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE
+        SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN,
+        SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE,
     };
     SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, SK_ARRAY_COUNT(colors),
                                                  SkShader::kClamp_TileMode);

src/effects/SkArithmeticMode.cpp

diff --git a/src/effects/SkArithmeticMode.cpp b/src/effects/SkArithmeticMode.cpp
index 7492cce..5bc48f1 100644
--- a/src/effects/SkArithmeticMode.cpp
+++ b/src/effects/SkArithmeticMode.cpp
@@ -73,12 +73,12 @@
             int da = SkGetPackedA32(dc);
 
             int srcNeedsUnpremul = needsUnpremul(sa);
-            int dstNeedsUnpremul = needsUnpremul(sa);
+            int dstNeedsUnpremul = needsUnpremul(da);
 
             int a, r, g, b;
 
             if (!srcNeedsUnpremul && !dstNeedsUnpremul) {
-                a = arith(k1, k2, k3, k4, sa, sa);
+                a = arith(k1, k2, k3, k4, sa, da);
                 r = arith(k1, k2, k3, k4, SkGetPackedR32(sc), SkGetPackedR32(dc));
                 g = arith(k1, k2, k3, k4, SkGetPackedG32(sc), SkGetPackedG32(dc));
                 b = arith(k1, k2, k3, k4, SkGetPackedB32(sc), SkGetPackedB32(dc));
@@ -103,7 +103,7 @@
                     db = SkUnPreMultiply::ApplyScale(scale, db);
                 }
 
-                a = arith(k1, k2, k3, k4, sa, sa);
+                a = arith(k1, k2, k3, k4, sa, da);
                 r = arith(k1, k2, k3, k4, sr, dr);
                 g = arith(k1, k2, k3, k4, sg, dg);
                 b = arith(k1, k2, k3, k4, sb, db);