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.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 */
33class FloatKeyframeSet extends KeyframeSet implements Keyframes.FloatKeyframes {
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        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
61    public void invalidateCache() {
62        firstTime = true;
63    }
64
65    @Override
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
141    public Class getType() {
142        return Float.class;
143    }
144}
145
146