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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_BUTTON_IMAGE_BUTTON_H_
      6 #define UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_
      7 
      8 #include "base/gtest_prod_util.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "ui/gfx/image/image_skia.h"
     11 #include "ui/views/controls/button/custom_button.h"
     12 
     13 namespace views {
     14 
     15 // An image button.
     16 
     17 // Note that this type of button is not focusable by default and will not be
     18 // part of the focus chain.  Call set_focusable(true) to make it part of the
     19 // focus chain.
     20 
     21 class VIEWS_EXPORT ImageButton : public CustomButton {
     22  public:
     23   enum HorizontalAlignment {
     24     ALIGN_LEFT = 0,
     25     ALIGN_CENTER,
     26     ALIGN_RIGHT
     27   };
     28 
     29   enum VerticalAlignment {
     30     ALIGN_TOP = 0,
     31     ALIGN_MIDDLE,
     32     ALIGN_BOTTOM
     33   };
     34 
     35   explicit ImageButton(ButtonListener* listener);
     36   virtual ~ImageButton();
     37 
     38   // Returns the image for a given |state|.
     39   virtual const gfx::ImageSkia& GetImage(ButtonState state) const;
     40 
     41   // Set the image the button should use for the provided state.
     42   virtual void SetImage(ButtonState state, const gfx::ImageSkia* image);
     43 
     44   // Set the background details.
     45   void SetBackground(SkColor color,
     46                      const gfx::ImageSkia* image,
     47                      const gfx::ImageSkia* mask);
     48 
     49   // Set an |image| to draw on top of the normal / hot / pushed image.
     50   // Pass NULL for no image.
     51   void SetOverlayImage(const gfx::ImageSkia* image);
     52 
     53   // Sets how the image is laid out within the button's bounds.
     54   void SetImageAlignment(HorizontalAlignment h_align,
     55                          VerticalAlignment v_align);
     56 
     57   // Overridden from View:
     58   virtual gfx::Size GetPreferredSize() OVERRIDE;
     59   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
     60 
     61   // Sets preferred size, so it could be correctly positioned in layout even if
     62   // it is NULL.
     63   void SetPreferredSize(const gfx::Size& preferred_size) {
     64     preferred_size_ = preferred_size;
     65   }
     66 
     67  protected:
     68   // Returns the image to paint. This is invoked from paint and returns a value
     69   // from images.
     70   virtual gfx::ImageSkia GetImageToPaint();
     71 
     72   // Updates button background for |scale_factor|.
     73   void UpdateButtonBackground(ui::ScaleFactor scale_factor);
     74 
     75   // The images used to render the different states of this button.
     76   gfx::ImageSkia images_[STATE_COUNT];
     77 
     78   gfx::ImageSkia background_image_;
     79 
     80   // Image to draw on top of normal / hot / pushed image.  Usually empty.
     81   gfx::ImageSkia overlay_image_;
     82 
     83  private:
     84   FRIEND_TEST_ALL_PREFIXES(ImageButtonTest, Basics);
     85   FRIEND_TEST_ALL_PREFIXES(ImageButtonTest, ImagePositionWithBorder);
     86 
     87   // Returns the correct position of the image for painting.
     88   gfx::Point ComputeImagePaintPosition(const gfx::ImageSkia& image);
     89 
     90   // Image alignment.
     91   HorizontalAlignment h_alignment_;
     92   VerticalAlignment v_alignment_;
     93   gfx::Size preferred_size_;
     94 
     95   DISALLOW_COPY_AND_ASSIGN(ImageButton);
     96 };
     97 
     98 ////////////////////////////////////////////////////////////////////////////////
     99 //
    100 // ToggleImageButton
    101 //
    102 // A toggle-able ImageButton.  It swaps out its graphics when toggled.
    103 //
    104 ////////////////////////////////////////////////////////////////////////////////
    105 class VIEWS_EXPORT ToggleImageButton : public ImageButton {
    106  public:
    107   explicit ToggleImageButton(ButtonListener* listener);
    108   virtual ~ToggleImageButton();
    109 
    110   // Change the toggled state.
    111   void SetToggled(bool toggled);
    112 
    113   // Like ImageButton::SetImage(), but to set the graphics used for the
    114   // "has been toggled" state.  Must be called for each button state
    115   // before the button is toggled.
    116   void SetToggledImage(ButtonState state, const gfx::ImageSkia* image);
    117 
    118   // Set the tooltip text displayed when the button is toggled.
    119   void SetToggledTooltipText(const string16& tooltip);
    120 
    121   // Overridden from ImageButton:
    122   virtual const gfx::ImageSkia& GetImage(ButtonState state) const OVERRIDE;
    123   virtual void SetImage(ButtonState state,
    124                         const gfx::ImageSkia* image) OVERRIDE;
    125 
    126   // Overridden from View:
    127   virtual bool GetTooltipText(const gfx::Point& p,
    128                               string16* tooltip) const OVERRIDE;
    129   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
    130 
    131  private:
    132   // The parent class's images_ member is used for the current images,
    133   // and this array is used to hold the alternative images.
    134   // We swap between the two when toggling.
    135   gfx::ImageSkia alternate_images_[STATE_COUNT];
    136 
    137   // True if the button is currently toggled.
    138   bool toggled_;
    139 
    140   // The parent class's tooltip_text_ is displayed when not toggled, and
    141   // this one is shown when toggled.
    142   string16 toggled_tooltip_text_;
    143 
    144   DISALLOW_COPY_AND_ASSIGN(ToggleImageButton);
    145 };
    146 
    147 }  // namespace views
    148 
    149 #endif  // UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_
    150