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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_AURA_WINDOW_DELEGATE_H_
      6 #define UI_AURA_WINDOW_DELEGATE_H_
      7 
      8 #include "base/compiler_specific.h"
      9 #include "base/memory/ref_counted.h"
     10 #include "ui/aura/aura_export.h"
     11 #include "ui/events/event_constants.h"
     12 #include "ui/events/event_handler.h"
     13 #include "ui/gfx/native_widget_types.h"
     14 
     15 namespace gfx {
     16 class Canvas;
     17 class Path;
     18 class Point;
     19 class Rect;
     20 class Size;
     21 }
     22 
     23 namespace ui {
     24 class GestureEvent;
     25 class KeyEvent;
     26 class Layer;
     27 class MouseEvent;
     28 class Texture;
     29 class TouchEvent;
     30 }
     31 
     32 namespace aura {
     33 
     34 // Delegate interface for aura::Window.
     35 class AURA_EXPORT WindowDelegate : public ui::EventHandler {
     36  public:
     37   // Returns the window's minimum size, or size 0,0 if there is no limit.
     38   virtual gfx::Size GetMinimumSize() const = 0;
     39 
     40   // Returns the window's maximum size, or size 0,0 if there is no limit.
     41   virtual gfx::Size GetMaximumSize() const = 0;
     42 
     43   // Called when the Window's position and/or size changes.
     44   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
     45                                const gfx::Rect& new_bounds) = 0;
     46 
     47   // Returns the native cursor for the specified point, in window coordinates,
     48   // or NULL for the default cursor.
     49   virtual gfx::NativeCursor GetCursor(const gfx::Point& point) = 0;
     50 
     51   // Returns the non-client component (see hit_test.h) containing |point|, in
     52   // window coordinates.
     53   virtual int GetNonClientComponent(const gfx::Point& point) const = 0;
     54 
     55   // Returns true if event handling should descend into |child|. |location| is
     56   // in terms of the Window.
     57   virtual bool ShouldDescendIntoChildForEventHandling(
     58       Window* child,
     59       const gfx::Point& location) = 0;
     60 
     61   // Returns true of the window can be focused.
     62   virtual bool CanFocus() = 0;
     63 
     64   // Invoked when mouse capture is lost on the window.
     65   virtual void OnCaptureLost() = 0;
     66 
     67   // Asks the delegate to paint window contents into the supplied canvas.
     68   virtual void OnPaint(gfx::Canvas* canvas) = 0;
     69 
     70   // Called when the window's device scale factor has changed.
     71   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) = 0;
     72 
     73   // Called from Window's destructor before OnWindowDestroyed and before the
     74   // children have been destroyed and the window has been removed from its
     75   // parent.
     76   // This method takes the window because the delegate implementation may no
     77   // longer have a route back to the window by the time this method is called.
     78   virtual void OnWindowDestroying(Window* window) = 0;
     79 
     80   // Called when the Window has been destroyed (i.e. from its destructor). This
     81   // is called after OnWindowDestroying and after the children have been
     82   // deleted and the window has been removed from its parent.
     83   // The delegate can use this as an opportunity to delete itself if necessary.
     84   // This method takes the window because the delegate implementation may no
     85   // longer have a route back to the window by the time this method is called.
     86   virtual void OnWindowDestroyed(Window* window) = 0;
     87 
     88   // Called when the TargetVisibility() of a Window changes. |visible|
     89   // corresponds to the target visibility of the window. See
     90   // Window::TargetVisibility() for details.
     91   virtual void OnWindowTargetVisibilityChanged(bool visible) = 0;
     92 
     93   // Called from Window::HitTest to check if the window has a custom hit test
     94   // mask. It works similar to the views counterparts. That is, if the function
     95   // returns true, GetHitTestMask below will be called to get the mask.
     96   // Otherwise, Window will hit-test against its bounds.
     97   virtual bool HasHitTestMask() const = 0;
     98 
     99   // Called from Window::HitTest to retrieve hit test mask when HasHitTestMask
    100   // above returns true.
    101   virtual void GetHitTestMask(gfx::Path* mask) const = 0;
    102 
    103  protected:
    104   virtual ~WindowDelegate() {}
    105 };
    106 
    107 }  // namespace aura
    108 
    109 #endif  // UI_AURA_WINDOW_DELEGATE_H_
    110