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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 
     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