cc: nine patch: add occlusion support

ash/mus/shadow.cc

 // Copyright 2015 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 "ash/mus/shadow.h"
 
 #include "ash/mus/property_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/layer.h"
@@ skipping 14 matching lines @@
 // curved corners that extend inwards beyond a window's borders.
 const int kActiveInteriorAperture = 134;
 const int kInactiveInteriorAperture = 134;
 const int kSmallInteriorAperture = 9;
 
 // Interior inset for different styles.
 const int kActiveInteriorInset = 64;
 const int kInactiveInteriorInset = 64;
 const int kSmallInteriorInset = 4;
 
+// Rounded corners are overdrawn on top of the window's content layer,
+// we need to exclude them from the occlusion area.
+const int kRoundedCornerRadius = 2;
+
 // Duration for opacity animation in milliseconds.
 const int kShadowAnimationDurationMs = 100;
 
 int GetShadowApertureForStyle(Shadow::Style style) {
   switch (style) {
     case Shadow::STYLE_ACTIVE:
       return kActiveInteriorAperture;
     case Shadow::STYLE_INACTIVE:
       return kInactiveInteriorAperture;
     case Shadow::STYLE_SMALL:
@@ skipping 142 matching lines @@
   gfx::Rect layer_bounds = content_bounds_;
   layer_bounds.Inset(-interior_inset_, -interior_inset_);
   layer()->SetBounds(layer_bounds);
   shadow_layer_->SetBounds(gfx::Rect(layer_bounds.size()));
 
   // Update the shadow aperture and border for style. Note that border is in
   // layer space and it cannot exceed the bounds of the layer.
   int aperture = GetShadowApertureForStyle(style_);
   int aperture_x = std::min(aperture, layer_bounds.width() / 2);
   int aperture_y = std::min(aperture, layer_bounds.height() / 2);
-  shadow_layer_->UpdateNinePatchLayerAperture(
-      gfx::Rect(aperture_x, aperture_y, image_size_.width() - aperture_x * 2,
-                image_size_.height() - aperture_y * 2));
+  gfx::Rect aperture_rect(aperture_x, aperture_y,
+                          image_size_.width() - aperture_x * 2,
+                          image_size_.height() - aperture_y * 2);
+
+  shadow_layer_->UpdateNinePatchLayerAperture(aperture_rect);
   shadow_layer_->UpdateNinePatchLayerBorder(
       gfx::Rect(aperture_x, aperture_y, aperture_x * 2, aperture_y * 2));
+
+  // The content bounds in the shadow's layer space are offsetted by
+  // |interior_inset_|. The occlusion area also has to be shrinked to
+  // allow rounded corners overdrawing on top of the window's content.
+  gfx::Rect content_bounds(
+      content_bounds_.x() + interior_inset_ + kRoundedCornerRadius,
+      content_bounds_.y() + interior_inset_ + kRoundedCornerRadius,
+      content_bounds_.width() - 2 * kRoundedCornerRadius,
+      content_bounds_.height() - 2 * kRoundedCornerRadius);
+  shadow_layer_->UpdateNinePatchOcclusion(content_bounds);
 }
 
 void Shadow::OnWindowDestroyed(::ui::Window* window) {
   DCHECK_EQ(window_, window);
   window_ = nullptr;
 }
 
 }  // namespace mus
 }  // namespace ash