ash/laser/laser_pointer_controller.h

// Copyright 2016 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_LASER_LASER_POINTER_CONTROLLER_H_
#define ASH_LASER_LASER_POINTER_CONTROLLER_H_

#include <memory>

#include "ash/ash_export.h"
#include "base/macros.h"
#include "ui/aura/window_observer.h"
#include "ui/events/event_handler.h"
#include "ui/gfx/geometry/point.h"

namespace base {
class Timer;
}

namespace ui {
class MouseEvent;
}

namespace ash {

class LaserPointerView;

// Controller for the laser pointer functionality. Enables/disables laser
// pointer as well as receives points and passes them off to be rendered.
class ASH_EXPORT LaserPointerController : public ui::EventHandler,
                                          public aura::WindowObserver {
 public:
  LaserPointerController();
  ~LaserPointerController() override;

  // Turns the laser pointer feature on or off. The user still has to press and
  // drag to see the laser pointer.
  void SetEnabled(bool enabled);

 private:
  friend class LaserPointerControllerTestApi;

  // ui::EventHandler:
  void OnMouseEvent(ui::MouseEvent* event) override;

  // aura::WindowObserver:
  void OnWindowDestroying(aura::Window* window) override;

  // Reparent, recreate or destroy LaserPointerView instance as needed based on
  // the current window and the widgets window.
  void SwitchTargetRootWindowIfNeeded(aura::Window* root_window);

  // Timer callback which adds a point where the mouse was last seen. This
  // allows the trail to fade away when the mouse is stationary.
  void AddStationaryPoint();

  // Timer which will add a new stationary point when the mouse stops moving.
  // This will remove points that are too old.
  std::unique_ptr<base::Timer> stationary_timer_;
  int stationary_timer_repeat_count_ = 0;

  bool enabled_ = false;

  // The last seen mouse location in screen coordinates.
  gfx::Point current_mouse_location_;

  // |laser_pointer_view_| will only hold an instance when the laser pointer is
  // enabled and activated (pressed or dragged).
  std::unique_ptr<LaserPointerView> laser_pointer_view_;

  DISALLOW_COPY_AND_ASSIGN(LaserPointerController);
};

}  // namespace ash

#endif  // ASH_LASER_LASER_POINTER_CONTROLLER_H_