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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 UI_GFX_SCREEN_H_
      6 #define UI_GFX_SCREEN_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "ui/base/ui_export.h"
     10 #include "ui/gfx/display.h"
     11 #include "ui/gfx/native_widget_types.h"
     12 #include "ui/gfx/point.h"
     13 #include "ui/gfx/screen_type_delegate.h"
     14 
     15 namespace gfx {
     16 class DisplayObserver;
     17 class Rect;
     18 
     19 // A utility class for getting various info about screen size, displays,
     20 // cursor position, etc.
     21 class UI_EXPORT Screen {
     22  public:
     23   // Retrieves the Screen that the specified NativeView belongs to. A value of
     24   // NULL is treated as |SCREEN_TYPE_NATIVE|.
     25   static Screen* GetScreenFor(NativeView view);
     26 
     27   // Returns the SCREEN_TYPE_NATIVE Screen. This should be used with caution,
     28   // as it is likely to be incorrect for code that runs on Windows.
     29   static Screen* GetNativeScreen();
     30 
     31   // Sets the global screen for a particular screen type. Only the _NATIVE
     32   // ScreenType must be provided.
     33   static void SetScreenInstance(ScreenType type, Screen* instance);
     34 
     35   // Returns the global screen for a particular type. Types other than _NATIVE
     36   // may be NULL.
     37   static Screen* GetScreenByType(ScreenType type);
     38 
     39   // Sets the global ScreenTypeDelegate. May be left unset if the platform
     40   // uses only the _NATIVE ScreenType.
     41   static void SetScreenTypeDelegate(ScreenTypeDelegate* delegate);
     42 
     43   Screen();
     44   virtual ~Screen();
     45 
     46   // Returns true if DIP is enabled.
     47   virtual bool IsDIPEnabled() = 0;
     48 
     49   // Returns the current absolute position of the mouse pointer.
     50   virtual gfx::Point GetCursorScreenPoint() = 0;
     51 
     52   // Returns the window under the cursor.
     53   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() = 0;
     54 
     55   // Returns the number of displays.
     56   // Mirrored displays are excluded; this method is intended to return the
     57   // number of distinct, usable displays.
     58   virtual int GetNumDisplays() = 0;
     59 
     60   // Returns the display nearest the specified window.
     61   virtual gfx::Display GetDisplayNearestWindow(NativeView view) const = 0;
     62 
     63   // Returns the the display nearest the specified point.
     64   virtual gfx::Display GetDisplayNearestPoint(
     65       const gfx::Point& point) const = 0;
     66 
     67   // Returns the display that most closely intersects the provided bounds.
     68   virtual gfx::Display GetDisplayMatching(
     69       const gfx::Rect& match_rect) const = 0;
     70 
     71   // Returns the primary display.
     72   virtual gfx::Display GetPrimaryDisplay() const = 0;
     73 
     74   // Adds/Removes display observers.
     75   virtual void AddObserver(DisplayObserver* observer) = 0;
     76   virtual void RemoveObserver(DisplayObserver* observer) = 0;
     77 
     78  private:
     79   DISALLOW_COPY_AND_ASSIGN(Screen);
     80 };
     81 
     82 Screen* CreateNativeScreen();
     83 
     84 }  // namespace gfx
     85 
     86 #endif  // UI_GFX_SCREEN_H_
     87