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_GFX_ANIMATION_LINEAR_ANIMATION_H_ 6 #define UI_GFX_ANIMATION_LINEAR_ANIMATION_H_ 7 8 #include "base/macros.h" 9 #include "base/time/time.h" 10 #include "ui/gfx/animation/animation.h" 11 12 namespace gfx { 13 14 class AnimationDelegate; 15 16 // Linear time bounded animation. As the animation progresses AnimateToState is 17 // invoked. 18 class ANIMATION_EXPORT LinearAnimation : public Animation { 19 public: 20 // Default frame rate (hz). 21 static const int kDefaultFrameRate; 22 23 // Initializes everything except the duration. 24 // 25 // Caller must make sure to call SetDuration() if they use this 26 // constructor; it is preferable to use the full one, but sometimes 27 // duration can change between calls to Start() and we need to 28 // expose this interface. 29 explicit LinearAnimation(AnimationDelegate* delegate, 30 int frame_rate = kDefaultFrameRate); 31 32 // Initializes all fields. 33 LinearAnimation(base::TimeDelta duration, 34 int frame_rate, 35 AnimationDelegate* delegate); 36 37 // Gets the value for the current state, according to the animation curve in 38 // use. This class provides only for a linear relationship, however subclasses 39 // can override this to provide others. 40 double GetCurrentValue() const override; 41 42 // Change the current state of the animation to |new_value|. 43 void SetCurrentValue(double new_value); 44 45 // Skip to the end of the current animation. 46 void End(); 47 48 // Changes the length of the animation. This resets the current 49 // state of the animation to the beginning. This value will be multiplied by 50 // the currently set scale factor. 51 void SetDuration(base::TimeDelta duration); 52 53 protected: 54 // Called when the animation progresses. Subclasses override this to 55 // efficiently update their state. AnimateToState(double state)56 virtual void AnimateToState(double state) {} 57 58 // Invoked by the AnimationContainer when the animation is running to advance 59 // the animation. Use |time_now| rather than Time::Now to avoid multiple 60 // animations running at the same time diverging. 61 void Step(base::TimeTicks time_now) override; 62 63 // Overriden to initialize state. 64 void AnimationStarted() override; 65 66 // Overriden to advance to the end (if End was invoked). 67 void AnimationStopped() override; 68 69 // Overriden to return true if state is not 1. 70 bool ShouldSendCanceledFromStop() override; 71 duration()72 base::TimeDelta duration() const { return duration_; } 73 74 private: 75 base::TimeDelta duration_; 76 77 // Current state, on a scale from 0.0 to 1.0. 78 double state_; 79 80 // If true, we're in end. This is used to determine if the animation should 81 // be advanced to the end from AnimationStopped. 82 bool in_end_; 83 84 DISALLOW_COPY_AND_ASSIGN(LinearAnimation); 85 }; 86 87 } // namespace gfx 88 89 #endif // APP_LINEAR_ANIMATION_H_ 90