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
