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      1 // Copyright 2013 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 CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_
      6 #define CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_
      7 
      8 #include "base/memory/scoped_ptr.h"
      9 #include "cc/animation/scrollbar_animation_controller.h"
     10 #include "cc/base/cc_export.h"
     11 
     12 namespace cc {
     13 class LayerImpl;
     14 
     15 // Scrollbar animation that partially fades and thins after an idle delay.
     16 class CC_EXPORT ScrollbarAnimationControllerThinning
     17     : public ScrollbarAnimationController {
     18  public:
     19   static scoped_ptr<ScrollbarAnimationControllerThinning> Create(
     20       LayerImpl* scroll_layer);
     21 
     22   static scoped_ptr<ScrollbarAnimationControllerThinning> CreateForTest(
     23       LayerImpl* scroll_layer,
     24       base::TimeDelta animation_delay,
     25       base::TimeDelta animation_duration);
     26 
     27   virtual ~ScrollbarAnimationControllerThinning();
     28 
     29   void set_mouse_move_distance_for_test(float distance) {
     30     mouse_move_distance_to_trigger_animation_ = distance;
     31   }
     32   bool mouse_is_over_scrollbar() const { return mouse_is_over_scrollbar_; }
     33   bool mouse_is_near_scrollbar() const { return mouse_is_near_scrollbar_; }
     34 
     35   // ScrollbarAnimationController overrides.
     36   virtual bool IsAnimating() const OVERRIDE;
     37   virtual base::TimeDelta DelayBeforeStart(base::TimeTicks now) const OVERRIDE;
     38 
     39   virtual bool Animate(base::TimeTicks now) OVERRIDE;
     40   virtual void DidScrollGestureBegin() OVERRIDE;
     41   virtual void DidScrollGestureEnd(base::TimeTicks now) OVERRIDE;
     42   virtual void DidMouseMoveOffScrollbar(base::TimeTicks now) OVERRIDE;
     43   virtual bool DidScrollUpdate(base::TimeTicks now) OVERRIDE;
     44   virtual bool DidMouseMoveNear(base::TimeTicks now, float distance) OVERRIDE;
     45 
     46  protected:
     47   ScrollbarAnimationControllerThinning(LayerImpl* scroll_layer,
     48                                        base::TimeDelta animation_delay,
     49                                        base::TimeDelta animation_duration);
     50 
     51  private:
     52   // Describes whether the current animation should INCREASE (darken / thicken)
     53   // a bar or DECREASE it (lighten / thin).
     54   enum AnimationChange {
     55     NONE,
     56     INCREASE,
     57     DECREASE
     58   };
     59   // Returns how far through the animation we are as a progress value from
     60   // 0 to 1.
     61   float AnimationProgressAtTime(base::TimeTicks now);
     62   float OpacityAtAnimationProgress(float progress);
     63   float ThumbThicknessScaleAtAnimationProgress(float progress);
     64   float AdjustScale(float new_value,
     65                     float current_value,
     66                     AnimationChange animation_change);
     67   void ApplyOpacityAndThumbThicknessScale(float opacity,
     68                                           float thumb_thickness_scale);
     69 
     70   LayerImpl* scroll_layer_;
     71 
     72   base::TimeTicks last_awaken_time_;
     73   bool mouse_is_over_scrollbar_;
     74   bool mouse_is_near_scrollbar_;
     75   // Are we narrowing or thickening the bars.
     76   AnimationChange thickness_change_;
     77   // Are we darkening or lightening the bars.
     78   AnimationChange opacity_change_;
     79   // Should the animation be delayed or start immediately.
     80   bool should_delay_animation_;
     81   // If |should_delay_animation_| is true, delay the animation by this amount.
     82   base::TimeDelta animation_delay_;
     83   // The time for the animation to run.
     84   base::TimeDelta animation_duration_;
     85   // How close should the mouse be to the scrollbar before we thicken it.
     86   float mouse_move_distance_to_trigger_animation_;
     87 
     88   DISALLOW_COPY_AND_ASSIGN(ScrollbarAnimationControllerThinning);
     89 };
     90 
     91 }  // namespace cc
     92 
     93 #endif  // CC_ANIMATION_SCROLLBAR_ANIMATION_CONTROLLER_THINNING_H_
     94