Respect window transparency when applying window shape.

ui/compositor/layer_unittest.cc

 // Copyright (c) 2012 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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/debug/trace_event.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 18 matching lines @@
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/test/context_factories_for_test.h"
 #include "ui/compositor/test/draw_waiter_for_test.h"
 #include "ui/compositor/test/test_compositor_host.h"
 #include "ui/compositor/test/test_layers.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/codec/png_codec.h"
 #include "ui/gfx/gfx_paths.h"
 #include "ui/gfx/skia_util.h"
 
+#if defined(OS_WIN)
+#include "ui/base/win/shell.h"
+#endif
+
 using cc::MatchesPNGFile;
 
 namespace ui {
 
 namespace {
 
 // There are three test classes in here that configure the Compositor and
 // Layer's slightly differently:
 // - LayerWithNullDelegateTest uses NullLayerDelegate as the LayerDelegate. This
 //   is typically the base class you want to use.
@@ skipping 829 matching lines @@
           << SkColorGetA(actual_color) << "); "
           << "expected RGBA=("
           << SkColorGetR(expected_color) << ","
           << SkColorGetG(expected_color) << ","
           << SkColorGetB(expected_color) << ","
           << SkColorGetA(expected_color) << ")";
     }
   }
 }
 
+// Checks that using the AlphaShape filter applied to a layer with
+// transparency, alpha-blends properly with the layer below.
+TEST_F(LayerWithRealCompositorTest, DrawAlphaThresholdFilterPixels) {
+  gfx::Size viewport_size = GetCompositor()->size();
+
+  int test_size = 200;
+  EXPECT_GE(viewport_size.width(), test_size);
+  EXPECT_GE(viewport_size.height(), test_size);
+
+  int blue_height = 10;
+  // Blue with a wee bit of transparency.
+  SkColor bluish = SkColorSetARGBInline(40, 0, 0, 255);

[Wez, 2014/08/26 01:53:39]

nit: translucent_blue?

+
+  bool alpha_blend = false;

[Wez, 2014/08/26 01:53:39]

expect_alpha_blend?

[garykac, 2014/09/02 19:27:06]

Done.

+#if defined(USE_AURA) && !defined(OS_CHROMEOS)
+  alpha_blend = true;
+#if defined(OS_WIN)
+  if (!ui::win::IsAeroGlassEnabled()) {

[Wez, 2014/08/26 01:53:39]

Do we need a similar test for Linux Aura, since we won't get desktop compositing
there unless we have a suitable window manager, configuration and GPU?

+    alpha_blend = false;
+  }
+#endif  // OS_WIN
+#endif  // USE_AURA && !OS_CHROMEOS
+
+  SkColor blue_over_red;
+  if (alpha_blend) {
+    // Transparent blue blended with red.
+    blue_over_red = SkColorSetARGBInline(255, 143, 143, 183);
+  } else {
+    // Transparent blue overwriting lower layer.

[Wez, 2014/08/26 01:53:38]

This is confusingly worded.

+    blue_over_red = SkColorSetARGBInline(255, 0, 0, 40);
+  }
+
+  scoped_ptr<Layer> layer(

[Wez, 2014/08/26 01:53:39]

layer1, or background_layer

[garykac, 2014/09/02 19:27:07]

Done.

+      CreateColorLayer(SK_ColorRED, gfx::Rect(viewport_size)));
+  scoped_ptr<Layer> layer2(

[Wez, 2014/08/26 01:53:38]

or blue_layer or foreground_layer

[garykac, 2014/09/02 19:27:06]

Done.

+      CreateColorLayer(bluish, gfx::Rect(viewport_size)));
+
+  SkRegion shape;
+  shape.setRect(0, 0, viewport_size.width(), blue_height);
+  layer2->SetAlphaShape(make_scoped_ptr(new SkRegion(shape)));
+
+  layer->Add(layer2.get());
+
+  DrawTree(layer.get());
+
+  SkBitmap bitmap;
+  ASSERT_TRUE(ReadPixels(&bitmap, gfx::Rect(viewport_size)));
+  ASSERT_FALSE(bitmap.empty());
+
+  SkAutoLockPixels lock(bitmap);
+  // Ignore the edge pixels since the blending can vary on some platforms.

[Wez, 2014/08/26 01:53:39]

This only seems to ignore the top-most and left-most, not the right-most nor
bottom-most edges?

[garykac, 2014/09/02 19:27:06]

The test size is much smaller than the window, so the right/bottom edges are
already being ignored.

+  for (int x = 1; x < test_size; x++) {
+    for (int y = 1; y < test_size; y++) {
+      SkColor actual_color = bitmap.getColor(x, y);
+      SkColor expected_color = y < blue_height ? blue_over_red : SK_ColorRED;
+      EXPECT_EQ(expected_color, actual_color)
+          << "Pixel error at x=" << x << " y=" << y << "; "
+          << "actual RGBA=("
+          << SkColorGetR(actual_color) << ","
+          << SkColorGetG(actual_color) << ","
+          << SkColorGetB(actual_color) << ","
+          << SkColorGetA(actual_color) << "); "
+          << "expected RGBA=("
+          << SkColorGetR(expected_color) << ","
+          << SkColorGetG(expected_color) << ","
+          << SkColorGetB(expected_color) << ","
+          << SkColorGetA(expected_color) << ")";
+    }
+  }
+}
+
 // Checks the logic around Compositor::SetRootLayer and Layer::SetCompositor.
 TEST_F(LayerWithRealCompositorTest, SetRootLayer) {
   Compositor* compositor = GetCompositor();
   scoped_ptr<Layer> l1(CreateColorLayer(SK_ColorRED,
                                         gfx::Rect(20, 20, 400, 400)));
   scoped_ptr<Layer> l2(CreateColorLayer(SK_ColorBLUE,
                                         gfx::Rect(10, 10, 350, 350)));
 
   EXPECT_EQ(NULL, l1->GetCompositor());
   EXPECT_EQ(NULL, l2->GetCompositor());
@@ skipping 687 matching lines @@
 
   c11->SetBounds(gfx::Rect(2, 2, 10, 10));
   SnapLayerToPhysicalPixelBoundary(root.get(), c11.get());
   // c11 is now off the pixel.
   // 0.5 / 1.5 = 0.333...
   EXPECT_EQ("0.33 0.33",
             Vector2dFTo100thPercisionString(c11->subpixel_position_offset()));
 }
 
 }  // namespace ui