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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_SLIDER_H_
      6 #define UI_VIEWS_CONTROLS_SLIDER_H_
      7 
      8 #include "ui/gfx/animation/animation_delegate.h"
      9 #include "ui/views/view.h"
     10 #include "ui/views/views_export.h"
     11 
     12 typedef unsigned int SkColor;
     13 
     14 namespace gfx {
     15 class ImageSkia;
     16 class SlideAnimation;
     17 }
     18 
     19 namespace views {
     20 
     21 class Slider;
     22 
     23 enum SliderChangeReason {
     24   VALUE_CHANGED_BY_USER,  // value was changed by the user (by clicking, e.g.)
     25   VALUE_CHANGED_BY_API,   // value was changed by a call to SetValue.
     26 };
     27 
     28 class VIEWS_EXPORT SliderListener {
     29  public:
     30   virtual void SliderValueChanged(Slider* sender,
     31                                   float value,
     32                                   float old_value,
     33                                   SliderChangeReason reason) = 0;
     34 
     35   // Invoked when a drag starts or ends (more specifically, when the mouse
     36   // button is pressed or released).
     37   virtual void SliderDragStarted(Slider* sender) {}
     38   virtual void SliderDragEnded(Slider* sender) {}
     39 
     40  protected:
     41   virtual ~SliderListener() {}
     42 };
     43 
     44 class VIEWS_EXPORT Slider : public View, public gfx::AnimationDelegate {
     45  public:
     46   enum Orientation {
     47     HORIZONTAL,
     48     VERTICAL
     49   };
     50 
     51   Slider(SliderListener* listener, Orientation orientation);
     52   virtual ~Slider();
     53 
     54   float value() const { return value_; }
     55   void SetValue(float value);
     56 
     57   // Set the delta used for changing the value via keyboard.
     58   void SetKeyboardIncrement(float increment);
     59 
     60   void SetAccessibleName(const string16& name);
     61 
     62   void set_enable_accessibility_events(bool enabled) {
     63     accessibility_events_enabled_ = enabled;
     64   }
     65 
     66   void set_focus_border_color(SkColor color) { focus_border_color_ = color; }
     67 
     68   // Update UI based on control on/off state.
     69   void UpdateState(bool control_on);
     70 
     71  private:
     72   void SetValueInternal(float value, SliderChangeReason reason);
     73 
     74   // Should be called on the Mouse Down event. Used to calculate relative
     75   // position of the mouse cursor (or the touch point) on the button to
     76   // accurately move the button using the MoveButtonTo() method.
     77   void PrepareForMove(const gfx::Point& point);
     78 
     79   // Moves the button to the specified point and updates the value accordingly.
     80   void MoveButtonTo(const gfx::Point& point);
     81 
     82   void OnPaintFocus(gfx::Canvas* canvas);
     83 
     84   // views::View overrides:
     85   virtual gfx::Size GetPreferredSize() OVERRIDE;
     86   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
     87   virtual bool OnMousePressed(const ui::MouseEvent& event) OVERRIDE;
     88   virtual bool OnMouseDragged(const ui::MouseEvent& event) OVERRIDE;
     89   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
     90   virtual bool OnKeyPressed(const ui::KeyEvent& event) OVERRIDE;
     91   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
     92 
     93   // ui::EventHandler overrides:
     94   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
     95 
     96   // gfx::AnimationDelegate overrides:
     97   virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
     98 
     99   SliderListener* listener_;
    100   Orientation orientation_;
    101 
    102   scoped_ptr<gfx::SlideAnimation> move_animation_;
    103 
    104   float value_;
    105   float keyboard_increment_;
    106   float animating_value_;
    107   bool value_is_valid_;
    108   string16 accessible_name_;
    109   bool accessibility_events_enabled_;
    110   SkColor focus_border_color_;
    111 
    112   // Relative position of the mouse cursor (or the touch point) on the slider's
    113   // button.
    114   gfx::Point initial_button_offset_;
    115 
    116   const int* bar_active_images_;
    117   const int* bar_disabled_images_;
    118   const gfx::ImageSkia* thumb_;
    119   const gfx::ImageSkia* images_[4];
    120   int bar_height_;
    121 
    122   DISALLOW_COPY_AND_ASSIGN(Slider);
    123 };
    124 
    125 }  // namespace views
    126 
    127 #endif  // UI_VIEWS_CONTROLS_SLIDER_H_
    128