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
17package android.animation;
18
19import android.animation.Keyframe.FloatKeyframe;
20
21import java.util.ArrayList;
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 */
33class FloatKeyframeSet extends KeyframeSet {
34    private float firstValue;
35    private float lastValue;
36    private float deltaValue;
37    private boolean firstTime = true;
38
39    public FloatKeyframeSet(FloatKeyframe... keyframes) {
40        super(keyframes);
41    }
42
43    @Override
44    public Object getValue(float fraction) {
45        return getFloatValue(fraction);
46    }
47
48    @Override
49    public FloatKeyframeSet clone() {
50        ArrayList<Keyframe> keyframes = mKeyframes;
51        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    public float getFloatValue(float fraction) {
61        if (mNumKeyframes == 2) {
62            if (firstTime) {
63                firstTime = false;
64                firstValue = ((FloatKeyframe) mKeyframes.get(0)).getFloatValue();
65                lastValue = ((FloatKeyframe) mKeyframes.get(1)).getFloatValue();
66                deltaValue = lastValue - firstValue;
67            }
68            if (mInterpolator != null) {
69                fraction = mInterpolator.getInterpolation(fraction);
70            }
71            if (mEvaluator == null) {
72                return firstValue + fraction * deltaValue;
73            } else {
74                return ((Number)mEvaluator.evaluate(fraction, firstValue, lastValue)).floatValue();
75            }
76        }
77        if (fraction <= 0f) {
78            final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
79            final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(1);
80            float prevValue = prevKeyframe.getFloatValue();
81            float nextValue = nextKeyframe.getFloatValue();
82            float prevFraction = prevKeyframe.getFraction();
83            float nextFraction = nextKeyframe.getFraction();
84            final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
85            if (interpolator != null) {
86                fraction = interpolator.getInterpolation(fraction);
87            }
88            float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
89            return mEvaluator == null ?
90                    prevValue + intervalFraction * (nextValue - prevValue) :
91                    ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
92                            floatValue();
93        } else if (fraction >= 1f) {
94            final FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 2);
95            final FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(mNumKeyframes - 1);
96            float prevValue = prevKeyframe.getFloatValue();
97            float nextValue = nextKeyframe.getFloatValue();
98            float prevFraction = prevKeyframe.getFraction();
99            float nextFraction = nextKeyframe.getFraction();
100            final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
101            if (interpolator != null) {
102                fraction = interpolator.getInterpolation(fraction);
103            }
104            float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
105            return mEvaluator == null ?
106                    prevValue + intervalFraction * (nextValue - prevValue) :
107                    ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
108                            floatValue();
109        }
110        FloatKeyframe prevKeyframe = (FloatKeyframe) mKeyframes.get(0);
111        for (int i = 1; i < mNumKeyframes; ++i) {
112            FloatKeyframe nextKeyframe = (FloatKeyframe) mKeyframes.get(i);
113            if (fraction < nextKeyframe.getFraction()) {
114                final TimeInterpolator interpolator = nextKeyframe.getInterpolator();
115                if (interpolator != null) {
116                    fraction = interpolator.getInterpolation(fraction);
117                }
118                float intervalFraction = (fraction - prevKeyframe.getFraction()) /
119                    (nextKeyframe.getFraction() - prevKeyframe.getFraction());
120                float prevValue = prevKeyframe.getFloatValue();
121                float nextValue = nextKeyframe.getFloatValue();
122                return mEvaluator == null ?
123                        prevValue + intervalFraction * (nextValue - prevValue) :
124                        ((Number)mEvaluator.evaluate(intervalFraction, prevValue, nextValue)).
125                            floatValue();
126            }
127            prevKeyframe = nextKeyframe;
128        }
129        // shouldn't get here
130        return ((Number)mKeyframes.get(mNumKeyframes - 1).getValue()).floatValue();
131    }
132
133}
134
135