ash/magnifier/partial_magnification_controller.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_
   6 #define ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_
   7
   8 #include "ui/aura/window_observer.h"
   9 #include "ui/events/event_handler.h"
  10 #include "ui/gfx/geometry/point.h"
  11 #include "ui/views/widget/widget_observer.h"
  12
  13 namespace ash {
  14
  15 const float kDefaultPartialMagnifiedScale = 1.5f;
  16 const float kNonPartialMagnifiedScale = 1.0f;
  17
  18 // Controls the partial screen magnifier, which is a small area of the screen
  19 // which is zoomed in.  The zoomed area follows the mouse cursor when enabled.
  20 class PartialMagnificationController
  21   : public ui::EventHandler,
  22     public aura::WindowObserver,
  23     public views::WidgetObserver {
  24  public:
  25   PartialMagnificationController();
  26   ~PartialMagnificationController() override;
  27
  28   // Enables (or disables if |enabled| is false) partial screen magnifier
  29   // feature.
  30   virtual void SetEnabled(bool enabled);
  31
  32   bool is_enabled() const { return is_enabled_; }
  33
  34   // Sets the magnification ratio. 1.0f means no magnification.
  35   void SetScale(float scale);
  36
  37   // Returns the current magnification ratio.
  38   float GetScale() const { return scale_; }
  39
  40  private:
  41   void OnMouseMove(const gfx::Point& location_in_root);
  42
  43   // Switch PartialMagnified RootWindow to |new_root_window|. This does
  44   // following:
  45   //  - Remove the magnifier from the current root window.
  46   //  - Create a magnifier in the new root_window |new_root_window|.
  47   //  - Switch the target window from current window to |new_root_window|.
  48   void SwitchTargetRootWindow(aura::Window* new_root_window);
  49
  50   // Returns the root window that contains the mouse cursor.
  51   aura::Window* GetCurrentRootWindow();
  52
  53   // Return true if the magnification scale > kMinPartialMagnifiedScaleThreshold
  54   bool IsPartialMagnified() const;
  55
  56   // Create the magnifier window.
  57   void CreateMagnifierWindow();
  58
  59   // Cleans up the window if needed.
  60   void CloseMagnifierWindow();
  61
  62   // Removes this as an observer of the zoom widget and the root window.
  63   void RemoveZoomWidgetObservers();
  64
  65   // ui::EventHandler overrides:
  66   void OnMouseEvent(ui::MouseEvent* event) override;
  67
  68   // Overridden from WindowObserver:
  69   void OnWindowDestroying(aura::Window* window) override;
  70
  71   // Overridden from WidgetObserver:
  72   void OnWidgetDestroying(views::Widget* widget) override;
  73
  74   bool is_enabled_;
  75
  76   // Current scale, origin (left-top) position of the magnification window.
  77   float scale_;
  78   gfx::Point origin_;
  79
  80   views::Widget* zoom_widget_;
  81
  82   DISALLOW_COPY_AND_ASSIGN(PartialMagnificationController);
  83 };
  84
  85 }  // namespace ash
  86
  87 #endif  // ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_