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/gfx/animation/animation_delegate.h" 11#include "ui/views/views_export.h" 12 13namespace gfx { 14class SlideAnimation; 15} 16 17namespace views { 18 19class 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 28class VIEWS_EXPORT ScrollAnimator : public gfx::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 gfx::AnimationDelegate. 44 virtual void AnimationEnded(const gfx::Animation* animation) OVERRIDE; 45 virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE; 46 virtual void AnimationCanceled(const gfx::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<gfx::SlideAnimation> animation_; 57 58 DISALLOW_COPY_AND_ASSIGN(ScrollAnimator); 59}; 60 61} // namespace views 62 63#endif // UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_ 64