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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_
#define UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_
#include <memory>
#include "base/memory/raw_ptr.h"
#include "ui/gfx/animation/animation_delegate.h"
#include "ui/views/views_export.h"
namespace gfx {
class SlideAnimation;
}
namespace views {
class VIEWS_EXPORT ScrollDelegate {
public:
// Returns true if the content was actually scrolled, false otherwise.
virtual bool OnScroll(float dx, float dy) = 0;
// Called when the contents scrolled by the fling event ended.
virtual void OnFlingScrollEnded() {}
protected:
~ScrollDelegate() = default;
};
class VIEWS_EXPORT ScrollAnimator : public gfx::AnimationDelegate {
public:
// The ScrollAnimator does not own the delegate. Uses default acceleration.
explicit ScrollAnimator(ScrollDelegate* delegate);
ScrollAnimator(const ScrollAnimator&) = delete;
ScrollAnimator& operator=(const ScrollAnimator&) = delete;
~ScrollAnimator() override;
// Use this if you would prefer different acceleration than the default.
void set_acceleration(float acceleration) { acceleration_ = acceleration; }
// Use this if you would prefer different velocity than the default.
void set_velocity_multiplier(float velocity_multiplier) {
velocity_multiplier_ = velocity_multiplier;
}
void Start(float velocity_x, float velocity_y);
void Stop();
bool is_scrolling() const { return !!animation_.get(); }
private:
// Implementation of gfx::AnimationDelegate.
void AnimationEnded(const gfx::Animation* animation) override;
void AnimationProgressed(const gfx::Animation* animation) override;
void AnimationCanceled(const gfx::Animation* animation) override;
raw_ptr<ScrollDelegate> delegate_;
float velocity_x_{0.f};
float velocity_y_{0.f};
float velocity_multiplier_{1.f};
float last_t_{0.f};
float duration_{0.f};
float acceleration_;
std::unique_ptr<gfx::SlideAnimation> animation_;
};
} // namespace views
#endif // UI_VIEWS_ANIMATION_SCROLL_ANIMATOR_H_
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