1 // Copyright (c) 2011 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_BASE_ANIMATION_LINEAR_ANIMATION_H_ 6 #define UI_BASE_ANIMATION_LINEAR_ANIMATION_H_ 7 8 #include "base/time/time.h" 9 #include "ui/base/animation/animation.h" 10 11 namespace ui { 12 13 class AnimationDelegate; 14 15 // Linear time bounded animation. As the animation progresses AnimateToState is 16 // invoked. 17 class UI_EXPORT LinearAnimation : public Animation { 18 public: 19 // Initializes everything except the duration. 20 // 21 // Caller must make sure to call SetDuration() if they use this 22 // constructor; it is preferable to use the full one, but sometimes 23 // duration can change between calls to Start() and we need to 24 // expose this interface. 25 LinearAnimation(int frame_rate, AnimationDelegate* delegate); 26 27 // Initializes all fields. 28 LinearAnimation(int duration, int frame_rate, AnimationDelegate* delegate); 29 30 // Gets the value for the current state, according to the animation curve in 31 // use. This class provides only for a linear relationship, however subclasses 32 // can override this to provide others. 33 virtual double GetCurrentValue() const OVERRIDE; 34 35 // Change the current state of the animation to |new_value|. 36 void SetCurrentValue(double new_value); 37 38 // Skip to the end of the current animation. 39 void End(); 40 41 // Changes the length of the animation. This resets the current 42 // state of the animation to the beginning. 43 void SetDuration(int duration); 44 45 protected: 46 // Called when the animation progresses. Subclasses override this to 47 // efficiently update their state. 48 virtual void AnimateToState(double state) {} 49 50 // Invoked by the AnimationContainer when the animation is running to advance 51 // the animation. Use |time_now| rather than Time::Now to avoid multiple 52 // animations running at the same time diverging. 53 virtual void Step(base::TimeTicks time_now) OVERRIDE; 54 55 // Overriden to initialize state. 56 virtual void AnimationStarted() OVERRIDE; 57 58 // Overriden to advance to the end (if End was invoked). 59 virtual void AnimationStopped() OVERRIDE; 60 61 // Overriden to return true if state is not 1. 62 virtual bool ShouldSendCanceledFromStop() OVERRIDE; 63 64 private: 65 base::TimeDelta duration_; 66 67 // Current state, on a scale from 0.0 to 1.0. 68 double state_; 69 70 // If true, we're in end. This is used to determine if the animation should 71 // be advanced to the end from AnimationStopped. 72 bool in_end_; 73 74 DISALLOW_COPY_AND_ASSIGN(LinearAnimation); 75 }; 76 77 } // namespace ui 78 79 #endif // APP_LINEAR_ANIMATION_H_ 80
