Merge 21606 - Our masker didn't account for the source image also having alph...

skia/ext/image_operations_unittest.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdlib.h>
 
 #include "skia/ext/image_operations.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
-#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkUnPreMultiply.h"
 
 namespace {
 
 // Computes the average pixel value for the given range, inclusive.
 uint32_t AveragePixel(const SkBitmap& bmp,
                       int x_min, int x_max,
                       int y_min, int y_max) {
   float accum[4] = {0, 0, 0, 0};
   int count = 0;
   for (int y = y_min; y <= y_max; y++) {
@@ skipping 190 matching lines @@
                                      i + 0 % 255);
   }
 
   SkBitmap masked = skia::ImageOperations::CreateMaskedBitmap(src, alpha);
 
   SkAutoLockPixels src_lock(src);
   SkAutoLockPixels masked_lock(masked);
   for (int y = 0; y < src_h; y++) {
     for (int x = 0; x < src_w; x++) {
       // Test that the alpha is equal.
-      SkColor src_pixel = *src.getAddr32(x, y);
-      SkColor alpha_pixel = *alpha.getAddr32(x, y);
+      SkColor src_pixel = SkUnPreMultiply::PMColorToColor(*src.getAddr32(x, y));
+      SkColor alpha_pixel =
+          SkUnPreMultiply::PMColorToColor(*alpha.getAddr32(x, y));
       SkColor masked_pixel = *masked.getAddr32(x, y);
 
-      // Test that the alpha is equal.
-      unsigned int alpha = (alpha_pixel & 0xff000000) >> SK_A32_SHIFT;
-      EXPECT_EQ(alpha, (masked_pixel & 0xff000000) >> SK_A32_SHIFT);
+      int alpha_value = SkAlphaMul(SkColorGetA(src_pixel),
+                                   SkColorGetA(alpha_pixel));
+      SkColor expected_pixel = SkColorSetARGB(
+          alpha_value,
+          SkAlphaMul(SkColorGetR(src_pixel), alpha_value),
+          SkAlphaMul(SkColorGetG(src_pixel), alpha_value),
+          SkAlphaMul(SkColorGetB(src_pixel), alpha_value));
 
-      // Test that the colors are right - SkBitmaps have premultiplied alpha,
-      // so we can't just do a direct comparison.
-      EXPECT_EQ(SkColorGetR(masked_pixel),
-                SkAlphaMul(SkColorGetR(src_pixel), alpha));
+      EXPECT_TRUE(ColorsClose(expected_pixel, masked_pixel));
     }
   }
 }
 
 // Testing blur without reimplementing the blur algorithm here is tough,
 // so we just check to see if the pixels have moved in the direction we
 // think they should move in (and also checking the wrapping behavior).
 // This will allow us to tweak the blur algorithm to suit speed/visual
 // needs without breaking the fundamentals.
 TEST(ImageOperations, CreateBlurredBitmap) {
@@ skipping 262 matching lines @@
   // Test multiple steps of downsampling.
   SkBitmap large;
   large.setConfig(SkBitmap::kARGB_8888_Config, 100, 43);
   large.allocPixels();
   result = skia::ImageOperations::DownsampleByTwoUntilSize(large, 6, 6);
 
   // The result should be divided in half 100x43 -> 50x22 -> 25x11
   EXPECT_EQ(25, result.width());
   EXPECT_EQ(11, result.height());
 }