chrome/browser/ui/panels/display_settings_provider.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 CHROME_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_
   6 #define CHROME_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_
   7
   8 #include "base/observer_list.h"
   9 #include "base/timer/timer.h"
  10 #include "ui/gfx/rect.h"
  11
  12 // Encapsulates the logic to provide display settings support, including the
  13 // information for:
  14 // 1) Work area
  15 // 2) Auto-hiding desktop bars, like Windows taskbar and MacOSX dock.
  16 class DisplaySettingsProvider {
  17  public:
  18   // Indicates which screen edge the desktop bar is aligned to.
  19   // We do not care about the desktop aligned to the top screen edge.
  20   enum DesktopBarAlignment {
  21     DESKTOP_BAR_ALIGNED_BOTTOM = 0,
  22     DESKTOP_BAR_ALIGNED_LEFT = 1,
  23     DESKTOP_BAR_ALIGNED_RIGHT = 2
  24   };
  25
  26   // Indicates current visibility state of the desktop bar.
  27   enum DesktopBarVisibility {
  28     DESKTOP_BAR_VISIBLE,
  29     DESKTOP_BAR_ANIMATING,
  30     DESKTOP_BAR_HIDDEN
  31   };
  32
  33   class DisplayObserver {
  34    public:
  35     virtual void OnDisplayChanged() = 0;
  36   };
  37
  38   class DesktopBarObserver {
  39    public:
  40     virtual void OnAutoHidingDesktopBarVisibilityChanged(
  41         DesktopBarAlignment alignment, DesktopBarVisibility visibility) = 0;
  42     virtual void OnAutoHidingDesktopBarThicknessChanged(
  43         DesktopBarAlignment alignment, int thickness) = 0;
  44   };
  45
  46   class FullScreenObserver {
  47    public:
  48     virtual void OnFullScreenModeChanged(bool is_full_screen) = 0;
  49   };
  50
  51   static DisplaySettingsProvider* Create();
  52
  53   virtual ~DisplaySettingsProvider();
  54
  55   // Subscribes/unsubscribes from the display settings change notification.
  56   void AddDisplayObserver(DisplayObserver* observer);
  57   void RemoveDisplayObserver(DisplayObserver* observer);
  58
  59   void AddDesktopBarObserver(DesktopBarObserver* observer);
  60   void RemoveDesktopBarObserver(DesktopBarObserver* observer);
  61
  62   void AddFullScreenObserver(FullScreenObserver* observer);
  63   void RemoveFullScreenObserver(FullScreenObserver* observer);
  64
  65   //
  66   // Display Area:
  67   //   This is the area of a display (monitor). There could be multiple display
  68   //   areas.
  69   // Work Area:
  70   //   This is the standard work area returned by the system. It is usually
  71   //   computed by the system as the part of display area that excludes
  72   //   top-most system menu or bars aligned to the screen edges.
  73   //
  74
  75   // Returns the bounds of primary display.
  76   virtual gfx::Rect GetPrimaryDisplayArea() const;
  77
  78   // Returns the bounds of the work area of primary display.
  79   virtual gfx::Rect GetPrimaryWorkArea() const;
  80
  81   // Returns the bounds of the display area that most closely intersects the
  82   // provided bounds.
  83   virtual gfx::Rect GetDisplayAreaMatching(const gfx::Rect& bounds) const;
  84
  85   // Returns the bounds of the work area that most closely intersects the
  86   // provided bounds.
  87   virtual gfx::Rect GetWorkAreaMatching(const gfx::Rect& bounds) const;
  88
  89   // Invoked when the display settings has changed, due to any of the following:
  90   // 1) screen resolution changes
  91   // 2) the thickness of desktop bar changes
  92   // 3) desktop bar switches between auto-hiding and non-auto-hiding
  93   virtual void OnDisplaySettingsChanged();
  94
  95   // Returns true if there is a desktop bar that is aligned to the specified
  96   // screen edge and set to auto-hide.
  97   virtual bool IsAutoHidingDesktopBarEnabled(DesktopBarAlignment alignment);
  98
  99   // Returns the thickness of the desktop bar that is aligned to the specified
 100   // screen edge, when it is visible. When the desktop bar is aligned to bottom
 101   // edge, this is the height of the bar. If the desktop bar is aligned to
 102   // left or right edge, this is the width of the bar.
 103   virtual int GetDesktopBarThickness(DesktopBarAlignment alignment) const;
 104
 105   // Returns the visibility state of the desktop bar that is aligned to the
 106   // specified screen edge.
 107   virtual DesktopBarVisibility GetDesktopBarVisibility(
 108       DesktopBarAlignment alignment) const;
 109
 110   ObserverList<DisplayObserver>& display_observers() {
 111     return display_observers_;
 112   }
 113
 114   ObserverList<DesktopBarObserver>& desktop_bar_observers() {
 115     return desktop_bar_observers_;
 116   }
 117
 118   ObserverList<FullScreenObserver>& full_screen_observers() {
 119     return full_screen_observers_;
 120   }
 121
 122   bool is_full_screen() const { return is_full_screen_; }
 123
 124  protected:
 125   enum FullScreenCheckMode {
 126     ASSUME_FULLSCREEN_ON,
 127     ASSUME_FULLSCREEN_OFF,
 128     PERFORM_FULLSCREEN_CHECK
 129   };
 130
 131   DisplaySettingsProvider();
 132
 133   // Returns true if we need to perform fullscreen check periodically.
 134   virtual bool NeedsPeriodicFullScreenCheck() const;
 135
 136   // Returns true if full screen or presentation mode in main screen is entered.
 137   virtual bool IsFullScreen();
 138
 139   // Callback to perform periodic check for full screen mode changes.
 140   void CheckFullScreenMode(FullScreenCheckMode check_mode);
 141
 142  private:
 143   // Observers that listen to various display settings changes.
 144   ObserverList<DisplayObserver> display_observers_;
 145   ObserverList<DesktopBarObserver> desktop_bar_observers_;
 146   ObserverList<FullScreenObserver> full_screen_observers_;
 147
 148   // True if full screen mode or presentation mode is entered.
 149   bool is_full_screen_;
 150
 151   // Timer used to detect full-screen mode change.
 152   base::RepeatingTimer<DisplaySettingsProvider> full_screen_mode_timer_;
 153
 154   DISALLOW_COPY_AND_ASSIGN(DisplaySettingsProvider);
 155 };
 156
 157 #endif  // CHROME_BROWSER_UI_PANELS_DISPLAY_SETTINGS_PROVIDER_H_