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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_VIEWS_CONTROLS_IMAGE_VIEW_H_
6 #define UI_VIEWS_CONTROLS_IMAGE_VIEW_H_
7 
8 #include "ui/gfx/image/image_skia.h"
9 #include "ui/views/view.h"
10 
11 namespace gfx {
12 class Canvas;
13 }
14 
15 namespace views {
16 
17 class Painter;
18 
19 /////////////////////////////////////////////////////////////////////////////
20 //
21 // ImageView class.
22 //
23 // An ImageView can display an image from an ImageSkia. If a size is provided,
24 // the ImageView will resize the provided image to fit if it is too big or will
25 // center the image if smaller. Otherwise, the preferred size matches the
26 // provided image size.
27 //
28 /////////////////////////////////////////////////////////////////////////////
29 class VIEWS_EXPORT ImageView : public View {
30  public:
31   enum Alignment {
32     LEADING = 0,
33     CENTER,
34     TRAILING
35   };
36 
37   ImageView();
38   virtual ~ImageView();
39 
40   // Set the image that should be displayed.
41   void SetImage(const gfx::ImageSkia& img);
42 
43   // Set the image that should be displayed from a pointer. Reset the image
44   // if the pointer is NULL. The pointer contents is copied in the receiver's
45   // image.
46   void SetImage(const gfx::ImageSkia* image_skia);
47 
48   // Returns the image currently displayed or NULL of none is currently set.
49   // The returned image is still owned by the ImageView.
50   const gfx::ImageSkia& GetImage();
51 
52   // Set the desired image size for the receiving ImageView.
53   void SetImageSize(const gfx::Size& image_size);
54 
55   // Return the preferred size for the receiving view. Returns false if the
56   // preferred size is not defined, which means that the view uses the image
57   // size.
58   bool GetImageSize(gfx::Size* image_size) const;
59 
60   // Returns the actual bounds of the visible image inside the view.
61   gfx::Rect GetImageBounds() const;
62 
63   // Reset the image size to the current image dimensions.
64   void ResetImageSize();
65 
66   // Set / Get the horizontal alignment.
67   void SetHorizontalAlignment(Alignment ha);
68   Alignment GetHorizontalAlignment() const;
69 
70   // Set / Get the vertical alignment.
71   void SetVerticalAlignment(Alignment va);
72   Alignment GetVerticalAlignment() const;
73 
74   // Set / Get the tooltip text.
75   void SetTooltipText(const base::string16& tooltip);
76   base::string16 GetTooltipText() const;
77 
set_interactive(bool interactive)78   void set_interactive(bool interactive) { interactive_ = interactive; }
79 
80   void SetFocusPainter(scoped_ptr<Painter> focus_painter);
81 
82   // Overriden from View:
83   virtual gfx::Size GetPreferredSize() const OVERRIDE;
84   virtual void OnFocus() OVERRIDE;
85   virtual void OnBlur() OVERRIDE;
86   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
87   virtual void GetAccessibleState(ui::AXViewState* state) OVERRIDE;
88   virtual bool GetTooltipText(const gfx::Point& p,
89                               base::string16* tooltip) const OVERRIDE;
90   virtual bool CanProcessEventsWithinSubtree() const OVERRIDE;
91 
92  private:
93   void OnPaintImage(gfx::Canvas* canvas);
94 
95   // Returns true if |img| is the same as the last image we painted. This is
96   // intended to be a quick check, not exhaustive. In other words it's possible
97   // for this to return false even though the images are in fact equal.
98   bool IsImageEqual(const gfx::ImageSkia& img) const;
99 
100   // Compute the image origin given the desired size and the receiver alignment
101   // properties.
102   gfx::Point ComputeImageOrigin(const gfx::Size& image_size) const;
103 
104   // Whether the image size is set.
105   bool image_size_set_;
106 
107   // The actual image size.
108   gfx::Size image_size_;
109 
110   // The underlying image.
111   gfx::ImageSkia image_;
112 
113   // Horizontal alignment.
114   Alignment horiz_alignment_;
115 
116   // Vertical alignment.
117   Alignment vert_alignment_;
118 
119   // The current tooltip text.
120   base::string16 tooltip_text_;
121 
122   // A flag controlling hit test handling for interactivity.
123   bool interactive_;
124 
125   // Scale last painted at.
126   float last_paint_scale_;
127 
128   // Address of bytes we last painted. This is used only for comparison, so its
129   // safe to cache.
130   void* last_painted_bitmap_pixels_;
131 
132   scoped_ptr<views::Painter> focus_painter_;
133 
134   DISALLOW_COPY_AND_ASSIGN(ImageView);
135 };
136 
137 }  // namespace views
138 
139 #endif  // UI_VIEWS_CONTROLS_IMAGE_VIEW_H_
140