Adding split view divider widget.

athena/wm/split_view_controller.h

 // Copyright 2014 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 ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_
 #define ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_
 
 #include "athena/athena_export.h"
+#include "athena/util/drag_handle.h"
 #include "athena/wm/bezel_controller.h"
+#include "athena/wm/public/window_manager_observer.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 
 namespace gfx {
 class Rect;
 class Transform;
 }
 
+namespace aura {
+class ScopedWindowTargeter;
+class Window;
+class WindowTargeter;
+}
+
+namespace views {
+class ViewTargeterDelegate;
+class Widget;
+}
+
 namespace athena {
 class WindowListProvider;
 class SplitViewControllerTest;
 
 // Responsible for entering split view mode, exiting from split view mode, and
 // laying out the windows in split view mode.
 class ATHENA_EXPORT SplitViewController
-    : public BezelController::ScrollDelegate {
+    : public BezelController::ScrollDelegate,
+      public DragHandleScrollDelegate,
+      public WindowManagerObserver {
  public:
   SplitViewController(aura::Window* container,
                       WindowListProvider* window_list_provider);
 
   virtual ~SplitViewController();
 
   bool IsSplitViewModeActive() const;
 
   // Activates split-view mode with |left| and |right| windows. If |left| and/or
   // |right| is NULL, then the first window in the window-list (which is neither
   // |left| nor |right|) is selected instead.
   void ActivateSplitMode(aura::Window* left, aura::Window* right);
 
   // Resets the internal state to an inactive state.
   void DeactivateSplitMode();
 
   // Replaces |window| in split-view mode with |replace_with|. Adjusts
   // |replace_with|'s visibility, transform and bounds. Resets |window|'s
   // visibility and transform but does not change its bounds.
   void ReplaceWindow(aura::Window* window,
                      aura::Window* replace_with);
 
-  // Returns the bounds that the left and right windows will have once split
-  // view is active and they are done animating. If |left_window_| and
-  // |right_window_| are still animating this may be different than their
-  // current bounds.
-  gfx::Rect GetLeftTargetBounds();
-  gfx::Rect GetRightTargetBounds();
+  // Returns the bounds of the left and right parts of the |container_| based
+  // on the current value of |divider_position_|.
+  gfx::Rect GetLeftAreaBounds();
+  gfx::Rect GetRightAreaBounds();
 
   aura::Window* left_window() { return left_window_; }
   aura::Window* right_window() { return right_window_; }
 
  private:
   friend class SplitViewControllerTest;
 
   enum State {
     // Split View mode is not active. |left_window_| and |right_window| are
     // NULL.
     INACTIVE,
     // Two windows |left_window_| and |right_window| are shown side by side and
-    // there is a horizontal scroll in progress which is dragging the separator
+    // there is a horizontal scroll in progress which is dragging the divider
     // between the two windows.
     SCROLLING,
     // Split View mode is active with |left_window_| and |right_window| showing
     // side by side each occupying half the screen. No scroll in progress.
     ACTIVE
   };
 
   void SetState(State state);
+
+  void InitializeDivider();
+  void HideDivider();
+  void ShowDivider();
+
   void UpdateLayout(bool animate);
 
   void SetWindowTransforms(const gfx::Transform& left_transform,
                            const gfx::Transform& right_transform,
+                           const gfx::Transform& divider_transform,
                            bool animate);
 
   // Called when the animation initiated by SetWindowTransforms() completes.
   void OnAnimationCompleted();
 
-  void UpdateSeparatorPositionFromScrollDelta(float delta);
+  // Returns the default divider position for when the split view mode is
+  // active and the divider is not being dragged.
+  int GetDefaultDividerPosition();
 
   // BezelController::ScrollDelegate:
-  virtual void ScrollBegin(BezelController::Bezel bezel, float delta) OVERRIDE;
-  virtual void ScrollEnd() OVERRIDE;
-  virtual void ScrollUpdate(float delta) OVERRIDE;
-  virtual bool CanScroll() OVERRIDE;
+  virtual void BezelScrollBegin(BezelController::Bezel bezel,
+                                float delta) OVERRIDE;
+  virtual void BezelScrollEnd() OVERRIDE;
+  virtual void BezelScrollUpdate(float delta) OVERRIDE;
+  virtual bool BezelCanScroll() OVERRIDE;
+
+  // DragHandleScrollDelegate:
+  virtual void HandleScrollBegin(float delta) OVERRIDE;
+  virtual void HandleScrollEnd() OVERRIDE;
+  virtual void HandleScrollUpdate(float delta) OVERRIDE;
+  virtual bool HandleCanScroll() OVERRIDE;
+
+  // WindowManagerObserver:
+  virtual void OnOverviewModeEnter() OVERRIDE;
+  virtual void OnOverviewModeExit() OVERRIDE;
+  virtual void OnSplitViewModeEnter() OVERRIDE;
+  virtual void OnSplitViewModeExit() OVERRIDE;
 
   State state_;
 
   aura::Window* container_;
 
   // Provider of the list of windows to cycle through. Not owned.
   WindowListProvider* window_list_provider_;
 
   // Windows for the left and right activities shown in SCROLLING and ACTIVE
   // states. In INACTIVE state these are NULL.
   aura::Window* left_window_;
   aura::Window* right_window_;
 
-  // Position of the separator between left_window_ and right_window_ in
-  // container_ coordinates (along the x axis).
-  int separator_position_;
+  // X-Coordinate of the (center of the) divider between left_window_ and
+  // right_window_ in |container_| coordinates.
+  int divider_position_;
+
+  // Meaningful only when state_ is SCROLLING.
+  // X-Coordinate of the divider when the scroll started.
+  int divider_scroll_start_position_;
+
+  // Visually separates the windows and contains the drag handle.
+  views::Widget* divider_widget_;
+
+  // The drag handle which can be used when split view is active to exit the
+  // split view mode.
+  views::View* drag_handle_;
+
+  scoped_ptr<aura::ScopedWindowTargeter> window_targeter_;
+  scoped_ptr<views::ViewTargeterDelegate> view_targeter_delegate_;
 
   base::WeakPtrFactory<SplitViewController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SplitViewController);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_