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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_GFX_ANIMATION_LINEAR_ANIMATION_H_
#define UI_GFX_ANIMATION_LINEAR_ANIMATION_H_
#include "base/macros.h"
#include "base/time/time.h"
#include "ui/gfx/animation/animation.h"
namespace gfx {
class AnimationDelegate;
// Linear time bounded animation. As the animation progresses AnimateToState is
// invoked.
class ANIMATION_EXPORT LinearAnimation : public Animation {
public:
// Default frame rate (hz).
static const int kDefaultFrameRate;
// Initializes everything except the duration.
//
// Caller must make sure to call SetDuration() if they use this
// constructor; it is preferable to use the full one, but sometimes
// duration can change between calls to Start() and we need to
// expose this interface.
explicit LinearAnimation(AnimationDelegate* delegate,
int frame_rate = kDefaultFrameRate);
// Initializes all fields.
LinearAnimation(base::TimeDelta duration,
int frame_rate,
AnimationDelegate* delegate);
LinearAnimation(const LinearAnimation&) = delete;
LinearAnimation& operator=(const LinearAnimation&) = delete;
// Gets the value for the current state, according to the animation curve in
// use. This class provides only for a linear relationship, however subclasses
// can override this to provide others.
double GetCurrentValue() const override;
// Change the current state of the animation to |new_value|.
void SetCurrentValue(double new_value);
// Skip to the end of the current animation.
void End();
// Changes the length of the animation. This resets the current
// state of the animation to the beginning. This value will be multiplied by
// the currently set scale factor.
void SetDuration(base::TimeDelta duration);
protected:
// Called when the animation progresses. Subclasses override this to
// efficiently update their state.
virtual void AnimateToState(double state) {}
// Invoked by the AnimationContainer when the animation is running to advance
// the animation. Use |time_now| rather than Time::Now to avoid multiple
// animations running at the same time diverging.
void Step(base::TimeTicks time_now) override;
// Overriden to initialize state.
void AnimationStarted() override;
// Overriden to advance to the end (if End was invoked).
void AnimationStopped() override;
// Overriden to return true if state is not 1.
bool ShouldSendCanceledFromStop() override;
base::TimeDelta duration() const { return duration_; }
private:
base::TimeDelta duration_;
// Current state, on a scale from 0.0 to 1.0.
double state_;
// If true, we're in end. This is used to determine if the animation should
// be advanced to the end from AnimationStopped.
bool in_end_;
};
} // namespace gfx
#endif // UI_GFX_ANIMATION_LINEAR_ANIMATION_H_