1 /*
2  * Copyright (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package android.animation;
18 
19 import android.animation.Keyframe.FloatKeyframe;
20 
21 import java.util.List;
22 
23 /**
24  * This class holds a collection of FloatKeyframe objects and is called by ValueAnimator to calculate
25  * values between those keyframes for a given animation. The class internal to the animation
26  * package because it is an implementation detail of how Keyframes are stored and used.
27  *
28  * <p>This type-specific subclass of KeyframeSet, along with the other type-specific subclass for
29  * int, exists to speed up the getValue() method when there is no custom
30  * TypeEvaluator set for the animation, so that values can be calculated without autoboxing to the
31  * Object equivalents of these primitive types.</p>
32  */
33 class FloatKeyframeSet extends KeyframeSet implements Keyframes.FloatKeyframes {
34     private float firstValue;
35     private float lastValue;
36     private float deltaValue;
37     private boolean firstTime = true;
38 
FloatKeyframeSet(FloatKeyframe... keyframes)39     public FloatKeyframeSet(FloatKeyframe... keyframes) {
40         super(keyframes);
41     }
42 
43     @Override
getValue(float fraction)44     public Object getValue(float fraction) {
45         return getFloatValue(fraction);
46     }
47 
48     @Override
clone()49     public FloatKeyframeSet clone() {
50         final List<Keyframe> keyframes = mKeyframes;
51         final int numKeyframes = mKeyframes.size();
52         FloatKeyframe[] newKeyframes = new FloatKeyframe[numKeyframes];
53         for (int i = 0; i < numKeyframes; ++i) {
54             newKeyframes[i] = (FloatKeyframe) keyframes.get(i).clone();
55         }
56         FloatKeyframeSet newSet = new FloatKeyframeSet(newKeyframes);
57         return newSet;
58     }
59 
60     @Override
invalidateCache()61     public void invalidateCache() {
62         firstTime = true;
63     }
64 
65     @Override
getFloatValue(float fraction)66     public float getFloatValue(float fraction) {
67         if (mNumKeyframes == 2) {
68             if (firstTime) {
69                 firstTime = false;
70                 firstValue = ((FloatKeyframe) mKeyframes.get(0)).getFloatValue();
71                 lastValue = ((FloatKeyframe) mKeyframes.get(1)).getFloatValue();
72                 deltaValue = lastValue - firstValue;
73             }
74             if (mInterpolator != null) {
75                 fraction = mInterpolator.getInterpolation(fraction);
76             }
77             if (mEvaluator == null) {
78                 return firstValue + fraction * deltaValue;
79             } else {
80                 return ((Number)mEvaluator.evaluate(fraction, firstValue, lastValue)).floatValue();
81             }
82         }
83         if (fraction <= 0f) {
84             final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
85             final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(1);
86             float prevValue = prevKeyframe.getFloatValue();
87             float nextValue = nextKeyframe.getFloatValue();
88             float prevFraction = prevKeyframe.getFraction();
89             float nextFraction = nextKeyframe.getFraction();
90             final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
91             if (interpolator != null) {
92                 fraction = interpolator.getInterpolation(fraction);
93             }
94             float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
95             return mEvaluator == null ?
96                     prevValue + intervalFraction * (nextValue - prevValue) :
97                     ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
98                             floatValue();
99         } else if (fraction >= 1f) {
100             final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 2);
101             final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 1);
102             float prevValue = prevKeyframe.getFloatValue();
103             float nextValue = nextKeyframe.getFloatValue();
104             float prevFraction = prevKeyframe.getFraction();
105             float nextFraction = nextKeyframe.getFraction();
106             final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
107             if (interpolator != null) {
108                 fraction = interpolator.getInterpolation(fraction);
109             }
110             float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
111             return mEvaluator == null ?
112                     prevValue + intervalFraction * (nextValue - prevValue) :
113                     ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
114                             floatValue();
115         }
116         FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
117         for (int i = 1; i < mNumKeyframes; ++i) {
118             FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(i);
119             if (fraction < nextKeyframe.getFraction()) {
120                 final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
121                 float intervalFraction = (fraction - prevKeyframe.getFraction()) /
122                     (nextKeyframe.getFraction() - prevKeyframe.getFraction());
123                 float prevValue = prevKeyframe.getFloatValue();
124                 float nextValue = nextKeyframe.getFloatValue();
125                 // Apply interpolator on the proportional duration.
126                 if (interpolator != null) {
127                     intervalFraction = interpolator.getInterpolation(intervalFraction);
128                 }
129                 return mEvaluator == null ?
130                         prevValue + intervalFraction * (nextValue - prevValue) :
131                         ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
132                             floatValue();
133             }
134             prevKeyframe = nextKeyframe;
135         }
136         // shouldn't get here
137         return ((Number)mKeyframes.get(mNumKeyframes - 1).getValue()).floatValue();
138     }
139 
140     @Override
getType()141     public Class getType() {
142         return Float.class;
143     }
144 }
145 
146