| // 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 ASH_WM_WINDOW_CYCLE_CONTROLLER_H_ |
| #define ASH_WM_WINDOW_CYCLE_CONTROLLER_H_ |
| |
| #include <memory> |
| |
| #include "ash/ash_export.h" |
| #include "base/macros.h" |
| #include "base/time/time.h" |
| |
| namespace aura { |
| class Window; |
| } |
| |
| namespace ash { |
| |
| class WindowCycleEventFilter; |
| class WindowCycleList; |
| |
| // Controls cycling through windows with the keyboard 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|. |
| void HandleCycleWindow(Direction direction); |
| |
| // Returns true if we are in the middle of a window cycling gesture. |
| bool IsCycling() const { return window_cycle_list_.get() != NULL; } |
| |
| // Call to start cycling windows. This function adds a pre-target handler to |
| // listen to the alt key release. |
| void StartCycling(); |
| |
| // Both of these functions stop the current window cycle and removes the event |
| // filter. The former indicates success (i.e. the new window should be |
| // activated) and the latter indicates that the interaction was cancelled (and |
| // the originally active window should remain active). |
| void CompleteCycling(); |
| void CancelCycling(); |
| |
| // Returns the WindowCycleList. |
| const WindowCycleList* window_cycle_list() const { |
| return window_cycle_list_.get(); |
| } |
| |
| private: |
| // Cycles to the next or previous window based on |direction|. |
| void Step(Direction direction); |
| |
| void StopCycling(); |
| |
| std::unique_ptr<WindowCycleList> window_cycle_list_; |
| |
| // Tracks what Window was active when starting to cycle and used to determine |
| // if the active Window changed in when ending cycling. |
| aura::Window* active_window_before_window_cycle_ = nullptr; |
| |
| // Non-null while actively cycling. |
| std::unique_ptr<WindowCycleEventFilter> event_filter_; |
| |
| base::Time cycle_start_time_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WindowCycleController); |
| }; |
| |
| } // namespace ash |
| |
| #endif // ASH_WM_WINDOW_CYCLE_CONTROLLER_H_ |