CrOS Tablet Window management - Split Screen part I

ash/wm/overview/window_selector_item.h

 // 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.
 
 #ifndef ASH_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_
 #define ASH_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 11 matching lines @@
 class SlideAnimation;
 }
 
 namespace views {
 class ImageButton;
 }
 
 namespace ash {
 
 class WindowSelector;
+class WindowGrid;
 
 // This class represents an item in overview mode.
 class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
                                       public aura::WindowObserver {
  public:
   // An image button with a close window icon.
   class OverviewCloseButton : public views::ImageButton {
    public:
     explicit OverviewCloseButton(views::ButtonListener* listener);
     ~OverviewCloseButton() override;
 
     // Resets the listener so that the listener can go out of scope.
     void ResetListener() { listener_ = nullptr; }
 
    private:
     DISALLOW_COPY_AND_ASSIGN(OverviewCloseButton);
   };
 
-  WindowSelectorItem(aura::Window* window, WindowSelector* window_selector);
+  WindowSelectorItem(aura::Window* window,
+                     WindowSelector* window_selector,
+                     WindowGrid* window_grid);
   ~WindowSelectorItem() override;
 
   aura::Window* GetWindow();
 
   // Returns the root window on which this item is shown.
   aura::Window* root_window() { return root_window_; }
 
   // Returns true if |target| is contained in this WindowSelectorItem.
   bool Contains(const aura::Window* target) const;
 
@@ skipping 52 matching lines @@
 
   const gfx::Rect& target_bounds() const { return target_bounds_; }
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
   // aura::WindowObserver:
   void OnWindowDestroying(aura::Window* window) override;
   void OnWindowTitleChanged(aura::Window* window) override;
 
+  // Handle the mouse/gesture event and facilitate dragging the item.
+  void HandlePressEvent(const gfx::Point& location_in_screen);
+  void HandleReleaseEvent(const gfx::Point& location_in_screen);
+  void HandleDragEvent(const gfx::Point& location_in_screen);
+
  private:
   class CaptionContainerView;
   class RoundedContainerView;
   friend class WindowSelectorTest;
 
   enum class HeaderFadeInMode {
     ENTER,
     UPDATE,
     EXIT,
   };
@@ skipping 26 matching lines @@
   void UpdateAccessibilityName();
 
   // Fades out a window caption when exiting overview mode.
   void FadeOut(std::unique_ptr<views::Widget> widget);
 
   // Allows a test to directly set animation state.
   gfx::SlideAnimation* GetBackgroundViewAnimation();
 
   aura::Window* GetOverviewWindowForMinimizedStateForTest();
 
+  // Called before dragging. Scales up the window a little bit to indicate its
+  // selection and stacks the window at the top of the Z order in order to keep
+  // it visible while dragging around.
+  void StartDrag();
+
+  // Called after dragging. Inserts the window back to its original stack order
+  // so that the windows orders are the same as when they entering overview.

[varkha, 2017/06/26 16:40:08]

nit (I think): the windows are ordered in the same order
   or
     the window order is the same
   or
     the order of windows is the same

[xdai1, 2017/06/26 21:44:00]

Done.

+  void EndDrag();
+
   // True if the item is being shown in the overview, false if it's being
   // filtered.
   bool dimmed_;
 
   // The root window this item is being displayed on.
   aura::Window* root_window_;
 
   // The contained Window's wrapper.
   ScopedTransformOverviewWindow transform_window_;
 
@@ skipping 29 matching lines @@
 
   // Pointer to the WindowSelector that owns the WindowGrid containing |this|.
   // Guaranteed to be non-null for the lifetime of |this|.
   WindowSelector* window_selector_;
 
   // Pointer to a view that covers the original header and has rounded top
   // corners. This view can have its color and opacity animated. It has a layer
   // which is the only textured layer used by the |item_widget_|.
   RoundedContainerView* background_view_;
 
+  // Pointer to the WindowGrid that contains |this|. Guaranteed to be non-null
+  // for the lifetime of |this|.
+  WindowGrid* window_grid_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowSelectorItem);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_OVERVIEW_WINDOW_SELECTOR_ITEM_H_