aura: Draw drop shadows under browsers and menus.

ui/aura_shell/shadow_controller.cc

+// Copyright (c) 2011 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 "ui/aura_shell/shadow_controller.h"
+
+#include <utility>
+
+#include "base/logging.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/shadow_types.h"
+#include "ui/aura/desktop.h"
+#include "ui/aura/window.h"
+#include "ui/aura_shell/shadow.h"
+
+using std::make_pair;
+
+namespace aura_shell {
+namespace internal {
+
+ShadowController::ShadowController() {
+  aura::Desktop::GetInstance()->AddObserver(this);
+}
+
+ShadowController::~ShadowController() {
+  for (WindowShadowMap::const_iterator it = window_shadows_.begin();
+       it != window_shadows_.end(); ++it) {
+    it->first->RemoveObserver(this);
+  }
+  aura::Desktop::GetInstance()->RemoveObserver(this);
+}
+
+void ShadowController::OnWindowInitialized(aura::Window* window) {
+  window->AddObserver(this);
+}
+
+void ShadowController::OnWindowParentChanged(aura::Window* window,
+                                             aura::Window* parent) {
+  Shadow* shadow = GetShadowForWindow(window);
+
+  if (parent) {
+    if (shadow) {
+      parent->layer()->Add(shadow->layer());
+      StackShadowBelowWindow(shadow, window);
+    } else {
+      if (ShouldShowShadowForWindow(window))
+        CreateShadowForWindow(window);
+    }
+  } else {
+    if (shadow && shadow->layer()->parent())
+      shadow->layer()->parent()->Remove(shadow->layer());
+  }
+}
+
+void ShadowController::OnPropertyChanged(aura::Window* window,
+                                         const char* name,
+                                         void* old) {
+  if (name == aura::kShadowTypeKey)
+    HandlePossibleShadowVisibilityChange(window);
+}
+
+void ShadowController::OnWindowVisibilityChanged(aura::Window* window,
+                                                 bool visible) {
+  HandlePossibleShadowVisibilityChange(window);
+}
+
+void ShadowController::OnWindowBoundsChanged(aura::Window* window,
+                                             const gfx::Rect& bounds) {
+  Shadow* shadow = GetShadowForWindow(window);
+  if (shadow)
+    shadow->SetContentBounds(bounds);
+}
+
+void ShadowController::OnWindowStackingChanged(aura::Window* window) {
+  Shadow* shadow = GetShadowForWindow(window);
+  if (shadow)
+    StackShadowBelowWindow(shadow, window);
+}
+
+void ShadowController::OnWindowDestroyed(aura::Window* window) {
+  window_shadows_.erase(window);
+}
+
+bool ShadowController::ShouldShowShadowForWindow(aura::Window* window) const {
+  const aura::ShadowType type = static_cast<aura::ShadowType>(
+      window->GetIntProperty(aura::kShadowTypeKey));
+  bool requested = false;
+  switch (type) {
+    case aura::SHADOW_TYPE_NONE:
+      break;
+    case aura::SHADOW_TYPE_RECTANGULAR:
+      requested = true;
+      break;
+    default:
+      NOTREACHED() << "Unknown shadow type " << type;
+  }
+
+  return requested && window->layer()->visible();
+}
+
+Shadow* ShadowController::GetShadowForWindow(aura::Window* window) {
+  WindowShadowMap::const_iterator it = window_shadows_.find(window);
+  return it != window_shadows_.end() ? it->second.get() : NULL;
+}
+
+void ShadowController::HandlePossibleShadowVisibilityChange(
+    aura::Window* window) {
+  const bool should_show = ShouldShowShadowForWindow(window);
+  Shadow* shadow = GetShadowForWindow(window);
+  if (shadow)
+    shadow->layer()->SetVisible(should_show);
+  else if (should_show && !shadow)
+    CreateShadowForWindow(window);
+}
+
+void ShadowController::CreateShadowForWindow(aura::Window* window) {
+  linked_ptr<Shadow> shadow(new Shadow());
+  window_shadows_.insert(make_pair(window, shadow));
+
+  shadow->Init();
+  shadow->SetContentBounds(window->bounds());
+  shadow->layer()->SetVisible(ShouldShowShadowForWindow(window));
+
+  if (window->parent()) {
+    window->parent()->layer()->Add(shadow->layer());
+    StackShadowBelowWindow(shadow.get(), window);
+  }
+}
+
+void ShadowController::StackShadowBelowWindow(Shadow* shadow,
+                                              aura::Window* window) {
+  ui::Layer* parent_layer = window->parent()->layer();
+  DCHECK_EQ(shadow->layer()->parent(), parent_layer);
+
+  // TODO(derat): Add a MoveBelow() method and use that instead (although we
+  // then run the risk of other layers getting stacked between a window and its
+  // shadow).
+  parent_layer->MoveAbove(shadow->layer(), window->layer());
+  parent_layer->MoveAbove(window->layer(), shadow->layer());
+}
+
+}  // namespace internal
+}  // namespace aura_shell