Home | History | Annotate | Download | only in animation
      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_ANIMATION_SCROLL_ANIMATOR_H_
      6 #define UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/memory/scoped_ptr.h"
     10 #include "ui/base/animation/animation_delegate.h"
     11 #include "ui/views/views_export.h"
     12 
     13 namespace ui {
     14 class SlideAnimation;
     15 }
     16 
     17 namespace views {
     18 
     19 class VIEWS_EXPORT ScrollDelegate {
     20  public:
     21   // Returns true if the content was actually scrolled, false otherwise.
     22   virtual bool OnScroll(float dx, float dy) = 0;
     23 
     24  protected:
     25   ~ScrollDelegate() {}
     26 };
     27 
     28 class VIEWS_EXPORT ScrollAnimator : public ui::AnimationDelegate {
     29  public:
     30   // The ScrollAnimator does not own the delegate. Uses default acceleration.
     31   explicit ScrollAnimator(ScrollDelegate* delegate);
     32   virtual ~ScrollAnimator();
     33 
     34   // Use this if you would prefer different acceleration than the default.
     35   void set_acceleration(float acceleration) { acceleration_ = acceleration; }
     36 
     37   void Start(float velocity_x, float velocity_y);
     38   void Stop();
     39 
     40   bool is_scrolling() const { return !!animation_.get(); }
     41 
     42  private:
     43   // Implementation of ui::AnimationDelegate.
     44   virtual void AnimationEnded(const ui::Animation* animation) OVERRIDE;
     45   virtual void AnimationProgressed(const ui::Animation* animation) OVERRIDE;
     46   virtual void AnimationCanceled(const ui::Animation* animation) OVERRIDE;
     47 
     48   ScrollDelegate* delegate_;
     49 
     50   float velocity_x_;
     51   float velocity_y_;
     52   float last_t_;
     53   float duration_;
     54   float acceleration_;
     55 
     56   scoped_ptr<ui::SlideAnimation> animation_;
     57 
     58   DISALLOW_COPY_AND_ASSIGN(ScrollAnimator);
     59 };
     60 
     61 }  // namespace views
     62 
     63 #endif  // UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_
     64