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/base/events/event_handler.h"
  10 #include "ui/gfx/point.h"
  11 #include "ui/views/widget/widget_observer.h"
  12
  13 namespace aura {
  14 class RootWindow;
  15 }
  16
  17 namespace ash {
  18
  19 const float kDefaultPartialMagnifiedScale = 1.5f;
  20 const float kNonPartialMagnifiedScale = 1.0f;
  21
  22 // Controls the partial screen magnifier, which is a small area of the screen
  23 // which is zoomed in.  The zoomed area follows the mouse cursor when enabled.
  24 class PartialMagnificationController
  25   : public ui::EventHandler,
  26     public aura::WindowObserver,
  27     public views::WidgetObserver {
  28  public:
  29   PartialMagnificationController();
  30   virtual ~PartialMagnificationController();
  31
  32   // Enables (or disables if |enabled| is false) partial screen magnifier
  33   // feature.
  34   virtual void SetEnabled(bool enabled);
  35
  36   bool is_enabled() const { return is_enabled_; }
  37
  38   // Sets the magnification ratio. 1.0f means no magnification.
  39   void SetScale(float scale);
  40
  41   // Returns the current magnification ratio.
  42   float GetScale() const { return scale_; }
  43
  44  private:
  45   void OnMouseMove(const gfx::Point& location_in_root);
  46
  47   // Switch PartialMagnified RootWindow to |new_root_window|. This does
  48   // following:
  49   //  - Remove the magnifier from the current root window.
  50   //  - Create a magnifier in the new root_window |new_root_window|.
  51   //  - Switch the target window from current window to |new_root_window|.
  52   void SwitchTargetRootWindow(aura::RootWindow* new_root_window);
  53
  54   // Returns the root window that contains the mouse cursor.
  55   aura::RootWindow* GetCurrentRootWindow();
  56
  57   // Return true if the magnification scale > kMinPartialMagnifiedScaleThreshold
  58   bool IsPartialMagnified() const;
  59
  60   // Create the magnifier window.
  61   void CreateMagnifierWindow();
  62
  63   // Cleans up the window if needed.
  64   void CloseMagnifierWindow();
  65
  66   // Removes this as an observer of the zoom widget and the root window.
  67   void RemoveZoomWidgetObservers();
  68
  69   // ui::EventHandler overrides:
  70   virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
  71
  72   // Overridden from WindowObserver:
  73   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
  74
  75   // Overridden from WidgetObserver:
  76   virtual void OnWidgetDestroying(views::Widget* widget) OVERRIDE;
  77
  78   // True if the magnified window is in motion of zooming or un-zooming effect.
  79   // Otherwise, false.
  80   bool is_on_zooming_;
  81
  82   bool is_enabled_;
  83
  84   // Current scale, origin (left-top) position of the magnification window.
  85   float scale_;
  86   gfx::Point origin_;
  87
  88   views::Widget* zoom_widget_;
  89
  90   DISALLOW_COPY_AND_ASSIGN(PartialMagnificationController);
  91 };
  92
  93 }  // namespace ash
  94
  95 #endif  // ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_