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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_WM_CORE_SHADOW_H_
6 #define UI_WM_CORE_SHADOW_H_
7 
8 #include "base/basictypes.h"
9 #include "base/memory/scoped_ptr.h"
10 #include "ui/compositor/layer_animation_observer.h"
11 #include "ui/gfx/rect.h"
12 #include "ui/wm/wm_export.h"
13 
14 namespace ui {
15 class Layer;
16 }  // namespace ui
17 
18 namespace wm {
19 
20 // Simple class that draws a drop shadow around content at given bounds.
21 class WM_EXPORT Shadow : public ui::ImplicitAnimationObserver {
22  public:
23   enum Style {
24     // Active windows have more opaque shadows, shifted down to make the window
25     // appear "higher".
26     STYLE_ACTIVE,
27 
28     // Inactive windows have less opaque shadows.
29     STYLE_INACTIVE,
30 
31     // Small windows like tooltips and context menus have lighter, smaller
32     // shadows.
33     STYLE_SMALL,
34   };
35 
36   Shadow();
37   virtual ~Shadow();
38 
39   void Init(Style style);
40 
41   // Returns |layer_.get()|. This is exposed so it can be added to the same
42   // layer as the content and stacked below it.  SetContentBounds() should be
43   // used to adjust the shadow's size and position (rather than applying
44   // transformations to this layer).
layer()45   ui::Layer* layer() const { return layer_.get(); }
46 
content_bounds()47   const gfx::Rect& content_bounds() const { return content_bounds_; }
style()48   Style style() const { return style_; }
49 
50   // Moves and resizes the shadow layer to frame |content_bounds|.
51   void SetContentBounds(const gfx::Rect& content_bounds);
52 
53   // Sets the shadow's style, animating opacity as necessary.
54   void SetStyle(Style style);
55 
56   // ui::ImplicitAnimationObserver overrides:
57   virtual void OnImplicitAnimationsCompleted() OVERRIDE;
58 
59  private:
60   // Updates the shadow images to the current |style_|.
61   void UpdateImagesForStyle();
62 
63   // Updates the shadow layer bounds based on the inteior inset and the current
64   // |content_bounds_|.
65   void UpdateLayerBounds();
66 
67   // The current style, set when the transition animation starts.
68   Style style_;
69 
70   // The parent layer of the shadow layer. It serves as a container accessible
71   // from the outside to control the visibility of the shadow.
72   scoped_ptr<ui::Layer> layer_;
73 
74   // The actual shadow layer corresponding to a cc::NinePatchLayer.
75   scoped_ptr<ui::Layer> shadow_layer_;
76 
77   // Size of the current shadow image.
78   gfx::Size image_size_;
79 
80   // Bounds of the content that the shadow encloses.
81   gfx::Rect content_bounds_;
82 
83   // The interior inset of the shadow images. The content bounds of the image
84   // grid should be set to |content_bounds_| inset by this amount.
85   int interior_inset_;
86 
87   DISALLOW_COPY_AND_ASSIGN(Shadow);
88 };
89 
90 }  // namespace wm
91 
92 #endif  // UI_WM_CORE_SHADOW_H_
93