From 6479f85bcd6d6e7347fe84c270fdc0e6f762863c Mon Sep 17 00:00:00 2001
From: "varunjain@chromium.org"
 <varunjain@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>
Date: Fri, 31 Aug 2012 22:47:38 +0000
Subject: Fix SkBitmapOperations::CreateMaskedBitmap. SkAlphaMul expects alpha
 value in range 0..256 while SkColor has values in 0..255.

BUG=none


Review URL: https://chromiumcodereview.appspot.com/10919037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@154524 0039d316-1c4b-4281-b951-d872f2087c98
---
 ui/gfx/image/image_skia_operations.cc  |  2 +-
 ui/gfx/skbitmap_operations.cc          | 11 +++++++----
 ui/gfx/skbitmap_operations_unittest.cc | 11 ++++++-----
 3 files changed, 14 insertions(+), 10 deletions(-)

(limited to 'ui')

diff --git a/ui/gfx/image/image_skia_operations.cc b/ui/gfx/image/image_skia_operations.cc
index c47b89b..d753f93 100644
--- a/ui/gfx/image/image_skia_operations.cc
+++ b/ui/gfx/image/image_skia_operations.cc
@@ -136,7 +136,7 @@ class TransparentImageSource : public gfx::ImageSkiaSource {
                     static_cast<int>(image_.size().width() * scale),
                     static_cast<int>(image_.size().height() * scale));
     alpha.allocPixels();
-    alpha.eraseColor(SkColorSetARGB(alpha_ * 256, 0, 0, 0));
+    alpha.eraseColor(SkColorSetARGB(alpha_ * 255, 0, 0, 0));
     return ImageSkiaRep(SkBitmapOperations::CreateMaskedBitmap(
         image_rep.sk_bitmap(), alpha),
                         image_rep.scale_factor());
diff --git a/ui/gfx/skbitmap_operations.cc b/ui/gfx/skbitmap_operations.cc
index 9f7262d..7e27506 100644
--- a/ui/gfx/skbitmap_operations.cc
+++ b/ui/gfx/skbitmap_operations.cc
@@ -155,11 +155,14 @@ SkBitmap SkBitmapOperations::CreateMaskedBitmap(const SkBitmap& rgb,
     for (int x = 0; x < masked.width(); ++x) {
       SkColor rgb_pixel = SkUnPreMultiply::PMColorToColor(rgb_row[x]);
       SkColor alpha_pixel = SkUnPreMultiply::PMColorToColor(alpha_row[x]);
-      int alpha = SkAlphaMul(SkColorGetA(rgb_pixel), SkColorGetA(alpha_pixel));
+      int alpha = SkAlphaMul(SkColorGetA(rgb_pixel),
+                             SkAlpha255To256(SkColorGetA(alpha_pixel)));
+      int alpha_256 = SkAlpha255To256(alpha);
       dst_row[x] = SkColorSetARGB(alpha,
-                                  SkAlphaMul(SkColorGetR(rgb_pixel), alpha),
-                                  SkAlphaMul(SkColorGetG(rgb_pixel), alpha),
-                                  SkAlphaMul(SkColorGetB(rgb_pixel), alpha));
+                                  SkAlphaMul(SkColorGetR(rgb_pixel), alpha_256),
+                                  SkAlphaMul(SkColorGetG(rgb_pixel), alpha_256),
+                                  SkAlphaMul(SkColorGetB(rgb_pixel),
+                                             alpha_256));
     }
   }
 
diff --git a/ui/gfx/skbitmap_operations_unittest.cc b/ui/gfx/skbitmap_operations_unittest.cc
index b263a6b..ae1e96c 100644
--- a/ui/gfx/skbitmap_operations_unittest.cc
+++ b/ui/gfx/skbitmap_operations_unittest.cc
@@ -197,14 +197,15 @@ TEST(SkBitmapOperationsTest, CreateMaskedBitmap) {
       SkColor masked_pixel = *masked.getAddr32(x, y);
 
       int alpha_value = SkAlphaMul(SkColorGetA(src_pixel),
-                                   SkColorGetA(alpha_pixel));
+                                   SkAlpha255To256(SkColorGetA(alpha_pixel)));
+      int alpha_value_256 = SkAlpha255To256(alpha_value);
       SkColor expected_pixel = SkColorSetARGB(
           alpha_value,
-          SkAlphaMul(SkColorGetR(src_pixel), alpha_value),
-          SkAlphaMul(SkColorGetG(src_pixel), alpha_value),
-          SkAlphaMul(SkColorGetB(src_pixel), alpha_value));
+          SkAlphaMul(SkColorGetR(src_pixel), alpha_value_256),
+          SkAlphaMul(SkColorGetG(src_pixel), alpha_value_256),
+          SkAlphaMul(SkColorGetB(src_pixel), alpha_value_256));
 
-      EXPECT_TRUE(ColorsClose(expected_pixel, masked_pixel));
+      EXPECT_EQ(expected_pixel, masked_pixel);
     }
   }
 }
-- 
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