Split Screen mode implementation

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/wm/bezel_controller.h"
+#include "athena/wm/public/window_manager_observer.h"
+#include "athena/wm/window_overview_mode.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+
+namespace gfx {
+class Transform;
+}
 
 namespace athena {
+class WindowListProvider;
+class WindowManager;
+class WindowOverviewModeDelegate;
 
 // Responsible for entering split view mode, exiting from split view mode, and
 // laying out the windows in split view mode.
-class SplitViewController : public BezelController::ScrollDelegate {
+class SplitViewController : public BezelController::ScrollDelegate,
+                            public WindowManagerObserver {
  public:
-  SplitViewController();
+  SplitViewController(aura::Window* container,
+                      WindowListProvider* window_list_provider,
+                      WindowManager* window_manager);
+
   virtual ~SplitViewController();
 
+  bool IsSplitViewModeActive() const;
+
  private:
+  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
+    // 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 UpdateLayout(bool animate);
+
+  void SetWindowTransform(aura::Window* left_window,
+                          const gfx::Transform& transform,
+                          bool animate);
+
+  void OnAnimationCompleted(aura::Window* window);
+
+  void UpdateSeparatorPositionFromScrollDelta(float delta);
+
+  // Returns the current activity shown to the user. Persists through the
+  // SCROLLING and ACTIVE states and gets updated if the current activity goes
+  // off screen when the user switches between activities.
+  aura::Window* GetCurrentActivityWindow();
+
   // BezelController::ScrollDelegate overrides.
   virtual void ScrollBegin(BezelController::Bezel bezel, float delta) OVERRIDE;
   virtual void ScrollEnd() OVERRIDE;
   virtual void ScrollUpdate(float delta) OVERRIDE;
   virtual bool CanScroll() OVERRIDE;
 
+  // WindowManagerObserver
+  virtual void OnOverviewModeEnter() OVERRIDE;
+  virtual void OnOverviewModeExit() OVERRIDE;
+
+  base::WeakPtrFactory<SplitViewController> weak_factory_;

[sadrul, 2014/08/09 13:32:40]

This should be the last member variable. (see
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/A9_N8p40l7A/eThX2...)

[mfomitchev, 2014/08/09 18:29:56]

Done, good to know, thanks for pointing this out.

+
+  State state_;
+
+  aura::Window* container_;
+  WindowManager* window_manager_;
+  // Provider of the list of windows to cycle through. Not owned.
+  WindowListProvider* window_list_provider_;
+
+  // Keeps track of the current activity shown as the user switches between
+  // activities. Persists through the SCROLLING and ACTIVE states. Gets reset
+  // to NULL when overview mode is activated.
+  aura::Window* current_activity_window_;
+
+  // 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_;
+
   DISALLOW_COPY_AND_ASSIGN(SplitViewController);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_WM_SPLIT_VIEW_CONTROLLER_H_