| // Copyright (c) 2012 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_WINDOW_CYCLE_CONTROLLER_H_ |
| #define ASH_WM_WINDOW_CYCLE_CONTROLLER_H_ |
| |
| #include "ash/ash_export.h" |
| #include "base/basictypes.h" |
| #include "base/memory/scoped_ptr.h" |
| |
| namespace ui { |
| class EventHandler; |
| } |
| |
| namespace ash { |
| |
| class WindowCycleList; |
| |
| // Controls cycling through windows with the keyboard, for example, via alt-tab. |
| // Windows are sorted primarily by most recently used, and then by screen order. |
| // We activate windows as you cycle through them, so the order on the screen |
| // may change during the gesture, but the most recently used list isn't updated |
| // until the cycling ends. Thus we maintain the state of the windows |
| // at the beginning of the gesture so you can cycle through in a consistent |
| // order. |
| class ASH_EXPORT WindowCycleController { |
| public: |
| enum Direction { |
| FORWARD, |
| BACKWARD |
| }; |
| WindowCycleController(); |
| virtual ~WindowCycleController(); |
| |
| // Returns true if cycling through windows is enabled. This is false at |
| // certain times, such as when the lock screen is visible. |
| static bool CanCycle(); |
| |
| // Cycles between windows in the given |direction|. If |is_alt_down| then |
| // interprets this call as the start of a multi-step cycle sequence and |
| // installs a key filter to watch for alt being released. |
| void HandleCycleWindow(Direction direction, bool is_alt_down); |
| |
| // Cycles between windows without maintaining a multi-step cycle sequence |
| // (see above). |
| void HandleLinearCycleWindow(); |
| |
| // Informs the controller that the Alt key has been released and it can |
| // terminate the existing multi-step cycle. |
| void AltKeyReleased(); |
| |
| // Returns true if we are in the middle of a window cycling gesture. |
| bool IsCycling() const { return windows_.get() != NULL; } |
| |
| // Returns the WindowCycleList. Really only useful for testing. |
| const WindowCycleList* windows() const { return windows_.get(); } |
| |
| private: |
| // Call to start cycling windows. You must call StopCycling() when done. |
| void StartCycling(); |
| |
| // Cycles to the next or previous window based on |direction|. |
| void Step(Direction direction); |
| |
| // Installs an event filter to watch for release of the alt key. |
| void InstallEventFilter(); |
| |
| // Stops the current window cycle and cleans up the event filter. |
| void StopCycling(); |
| |
| scoped_ptr<WindowCycleList> windows_; |
| |
| // Event handler to watch for release of alt key. |
| scoped_ptr<ui::EventHandler> event_handler_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WindowCycleController); |
| }; |
| |
| } // namespace ash |
| |
| #endif // ASH_WM_WINDOW_CYCLE_CONTROLLER_H_ |