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      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/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   virtual ~PartialMagnificationController();
     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   virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
     67 
     68   // Overridden from WindowObserver:
     69   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
     70 
     71   // Overridden from WidgetObserver:
     72   virtual void OnWidgetDestroying(views::Widget* widget) OVERRIDE;
     73 
     74   // True if the magnified window is in motion of zooming or un-zooming effect.
     75   // Otherwise, false.
     76   bool is_on_zooming_;
     77 
     78   bool is_enabled_;
     79 
     80   // Current scale, origin (left-top) position of the magnification window.
     81   float scale_;
     82   gfx::Point origin_;
     83 
     84   views::Widget* zoom_widget_;
     85 
     86   DISALLOW_COPY_AND_ASSIGN(PartialMagnificationController);
     87 };
     88 
     89 }  // namespace ash
     90 
     91 #endif  // ASH_MAGNIFIER_PARTIAL_MAGNIFICATION_CONTROLLER_H_
     92