CrOS Tablet Window management - Split Screen part I

ash/wm/overview/window_selector_item.cc

 // Copyright 2013 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/wm/overview/window_selector_item.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "ash/metrics/user_metrics_action.h"
@@ skipping 81 matching lines @@
 // Duration of background opacity transition for the selected label.
 static const int kSelectorFadeInMilliseconds = 350;
 
 // Duration of background opacity transition when exiting overview mode.
 static const int kExitFadeInMilliseconds = 30;
 
 // Before closing a window animate both the window and the caption to shrink by
 // this fraction of size.
 static const float kPreCloseScale = 0.02f;
 
+// Before dragging an overview window, the window will scale up |kPreDragScale|
+// to indicate its selection.
+static const float kPreDragScale = 0.04f;

[oshima, 2017/06/14 05:45:47]

The scale will be applied during drag, correct? How about DragWindowScale?

[xdai1, 2017/06/15 22:11:42]

Yes. It will be applied during drag. Done.

+
 // Convenience method to fade in a Window with predefined animation settings.
 // Note: The fade in animation will occur after a delay where the delay is how
 // long the lay out animations take.
 void SetupFadeInAfterLayout(views::Widget* widget) {
   aura::Window* window = widget->GetNativeWindow();
   window->layer()->SetOpacity(0.0f);
   ScopedOverviewAnimationSettings scoped_overview_animation_settings(
       OverviewAnimationType::OVERVIEW_ANIMATION_ENTER_OVERVIEW_MODE_FADE_IN,
       window);
   window->layer()->SetOpacity(1.0f);
 }
 
-// A Button that has a listener and listens to mouse clicks on the visible part
-// of an overview window.
+// A Button that has a listener and listens to mouse / gesture events on the
+// visible part of an overview window. Note the drag events are only handled in
+// maximized mode.
 class ShieldButton : public views::CustomButton {
  public:
   ShieldButton(views::ButtonListener* listener, const base::string16& name)
       : views::CustomButton(listener) {
     SetAccessibleName(name);
   }
   ~ShieldButton() override {}
 
   // When WindowSelectorItem (which is a ButtonListener) is destroyed, its
   // |item_widget_| is allowed to stay around to complete any animations.
   // Resetting the listener in all views that are targeted by events is
   // necessary to prevent a crash when a user clicks on the fading out widget
   // after the WindowSelectorItem has been destroyed.
   void ResetListener() { listener_ = nullptr; }
 
+  // views::CustomButton overrides:
+  bool OnMousePressed(const ui::MouseEvent& event) override {
+    if (listener() && SplitViewController::ShouldAllowSplitView()) {
+      gfx::Point location(event.location());
+      views::View::ConvertPointToScreen(this, &location);
+      listener()->HandlePressEvent(location);
+      return true;
+    }
+    return views::CustomButton::OnMousePressed(event);
+  }
+
+  void OnMouseReleased(const ui::MouseEvent& event) override {
+    if (listener() && SplitViewController::ShouldAllowSplitView()) {
+      gfx::Point location(event.location());
+      views::View::ConvertPointToScreen(this, &location);
+      listener()->HandleReleaseEvent(location);
+      return;
+    }
+    views::CustomButton::OnMouseReleased(event);
+  }
+
+  bool OnMouseDragged(const ui::MouseEvent& event) override {
+    if (listener() && SplitViewController::ShouldAllowSplitView()) {
+      gfx::Point location(event.location());
+      views::View::ConvertPointToScreen(this, &location);
+      listener()->HandleDragEvent(location);
+      return true;
+    }
+    return views::CustomButton::OnMouseDragged(event);
+  }
+
+  void OnGestureEvent(ui::GestureEvent* event) override {
+    if (listener() && SplitViewController::ShouldAllowSplitView()) {
+      gfx::Point location(event->location());
+      views::View::ConvertPointToScreen(this, &location);
+      switch (event->type()) {
+        case ui::ET_GESTURE_SCROLL_BEGIN:
+        case ui::ET_GESTURE_TAP_DOWN: {
+          listener()->HandlePressEvent(location);
+          break;
+        }
+        case ui::ET_GESTURE_SCROLL_UPDATE:
+          listener()->HandleDragEvent(location);
+          break;
+        case ui::ET_GESTURE_END:
+          listener()->HandleReleaseEvent(location);
+          break;
+        default:
+          break;
+      }
+      event->SetHandled();
+      return;
+    }
+    views::CustomButton::OnGestureEvent(event);
+  }
+
+  WindowSelectorItem* listener() {
+    return static_cast<WindowSelectorItem*>(listener_);
+  }
+
  protected:
   // views::View:
   const char* GetClassName() const override { return "ShieldButton"; }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ShieldButton);
 };
 
 }  // namespace
 
@@ skipping 250 matching lines @@
   views::Label* label_;
   views::ImageButton* close_button_;
 
   DISALLOW_COPY_AND_ASSIGN(CaptionContainerView);
 };
 
 WindowSelectorItem::WindowSelectorItem(aura::Window* window,
                                        WindowSelector* window_selector)
     : dimmed_(false),
       root_window_(window->GetRootWindow()),
-      transform_window_(window),
+      transform_window_(this, window),
       in_bounds_update_(false),
       selected_(false),
       caption_container_view_(nullptr),
       label_view_(nullptr),
       close_button_(new OverviewCloseButton(this)),
       window_selector_(window_selector),
       background_view_(nullptr) {
   CreateWindowLabel(window->GetTitle());
   GetWindow()->AddObserver(this);
 }
@@ skipping 115 matching lines @@
 }
 
 void WindowSelectorItem::ButtonPressed(views::Button* sender,
                                        const ui::Event& event) {
   if (sender == close_button_) {
     ShellPort::Get()->RecordUserMetricsAction(UMA_WINDOW_OVERVIEW_CLOSE_BUTTON);
     CloseWindow();
     return;
   }
   CHECK(sender == caption_container_view_->listener_button());
-  window_selector_->SelectWindow(this);
+
+  // For other cases, the event is handled in OverviewWindowDragController.
+  if (!SplitViewController::ShouldAllowSplitView()) {
+    window_selector_->SelectWindow(this);
+  }
 }
 
 void WindowSelectorItem::OnWindowDestroying(aura::Window* window) {
   window->RemoveObserver(this);
   transform_window_.OnWindowDestroyed();
 }
 
 void WindowSelectorItem::OnWindowTitleChanged(aura::Window* window) {
   // TODO(flackr): Maybe add the new title to a vector of titles so that we can
   // filter any of the titles the window had while in the overview session.
   label_view_->SetText(window->GetTitle());
   UpdateAccessibilityName();
 }
 
 float WindowSelectorItem::GetItemScale(const gfx::Size& size) {
   gfx::Size inset_size(size.width(), size.height() - 2 * kWindowMargin);
   return ScopedTransformOverviewWindow::GetItemScale(
       transform_window_.GetTargetBoundsInScreen().size(), inset_size,
       transform_window_.GetTopInset(),
       close_button_->GetPreferredSize().height());
 }
 
+void WindowSelectorItem::HandlePressEvent(
+    const gfx::Point& location_in_screen) {
+  PrepareDrag();
+  window_selector_->InitiateDrag(this, location_in_screen);
+}
+
+void WindowSelectorItem::HandleReleaseEvent(
+    const gfx::Point& location_in_screen) {
+  EndDrag();
+  window_selector_->CompleteDrag(this);
+}
+
+void WindowSelectorItem::HandleDragEvent(const gfx::Point& location_in_screen) {
+  window_selector_->Drag(this, location_in_screen);
+}
+
 gfx::Rect WindowSelectorItem::GetTargetBoundsInScreen() const {
   return transform_window_.GetTargetBoundsInScreen();
 }
 
 void WindowSelectorItem::SetItemBounds(const gfx::Rect& target_bounds,
                                        OverviewAnimationType animation_type) {
   DCHECK(root_window_ == GetWindow()->GetRootWindow());
   gfx::Rect screen_rect = transform_window_.GetTargetBoundsInScreen();
 
   // Avoid division by zero by ensuring screen bounds is not empty.
@@ skipping 170 matching lines @@
 }
 
 gfx::SlideAnimation* WindowSelectorItem::GetBackgroundViewAnimation() {
   return background_view_ ? background_view_->animation() : nullptr;
 }
 
 aura::Window* WindowSelectorItem::GetOverviewWindowForMinimizedStateForTest() {
   return transform_window_.GetOverviewWindowForMinimizedState();
 }
 
+void WindowSelectorItem::PrepareDrag() {
+  gfx::Rect scaled_bounds(target_bounds_);
+  scaled_bounds.Inset(-target_bounds_.width() * kPreDragScale,
+                      -target_bounds_.height() * kPreDragScale);
+  OverviewAnimationType animation_type =
+      OverviewAnimationType::OVERVIEW_ANIMATION_CLOSING_SELECTOR_ITEM;
+  SetBounds(scaled_bounds, animation_type);
+
+  aura::Window* widget_window = item_widget_->GetNativeWindow();
+  if (widget_window && widget_window->parent() == GetWindow()->parent()) {
+    widget_window->parent()->StackChildAtTop(widget_window);
+    widget_window->parent()->StackChildBelow(GetWindow(), widget_window);

[oshima, 2017/06/14 05:45:47]

This will not work if there is always on top window. You don't have to fix this
soon, but please file a bug + add TODO.

[xdai1, 2017/06/15 22:11:42]

Done.

+  }
+}
+
+void WindowSelectorItem::EndDrag() {
+  aura::Window* widget_window = item_widget_->GetNativeWindow();
+  if (widget_window && widget_window->parent() == GetWindow()->parent()) {
+    widget_window->parent()->StackChildAtBottom(widget_window);
+    widget_window->parent()->StackChildBelow(GetWindow(), widget_window);
+  }
+}
+
 }  // namespace ash