IntKeyframeSet.java
/*
* Copyright 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.core.animation;
import androidx.annotation.NonNull;
import androidx.core.animation.Keyframe.IntKeyframe;
import java.util.List;
/**
* This class holds a collection of IntKeyframe objects and is called by ValueAnimator to calculate
* values between those keyframes for a given animation. The class internal to the animation
* package because it is an implementation detail of how Keyframes are stored and used.
*
* <p>This type-specific subclass of KeyframeSet, along with the other type-specific subclass for
* float, exists to speed up the getValue() method when there is no custom
* TypeEvaluator set for the animation, so that values can be calculated without autoboxing to the
* Object equivalents of these primitive types.</p>
*/
class IntKeyframeSet extends KeyframeSet<Integer> implements Keyframes.IntKeyframes {
IntKeyframeSet(IntKeyframe... keyframes) {
super(keyframes);
}
@Override
public Integer getValue(float fraction) {
return getIntValue(fraction);
}
@NonNull
@Override
public IntKeyframeSet clone() {
List<Keyframe<Integer>> keyframes = mKeyframes;
int numKeyframes = mKeyframes.size();
IntKeyframe[] newKeyframes = new IntKeyframe[numKeyframes];
for (int i = 0; i < numKeyframes; ++i) {
newKeyframes[i] = (IntKeyframe) keyframes.get(i).clone();
}
IntKeyframeSet newSet = new IntKeyframeSet(newKeyframes);
return newSet;
}
@Override
public int getIntValue(float fraction) {
if (fraction <= 0f) {
final IntKeyframe prevKeyframe = (IntKeyframe) mKeyframes.get(0);
final IntKeyframe nextKeyframe = (IntKeyframe) mKeyframes.get(1);
int prevValue = prevKeyframe.getIntValue();
int nextValue = nextKeyframe.getIntValue();
float prevFraction = prevKeyframe.getFraction();
float nextFraction = nextKeyframe.getFraction();
final Interpolator interpolator = nextKeyframe.getInterpolator();
if (interpolator != null) {
fraction = interpolator.getInterpolation(fraction);
}
float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
return mEvaluator == null
? prevValue + (int) (intervalFraction * (nextValue - prevValue)) :
mEvaluator.evaluate(intervalFraction, prevValue, nextValue).intValue();
} else if (fraction >= 1f) {
final IntKeyframe prevKeyframe = (IntKeyframe) mKeyframes.get(mNumKeyframes - 2);
final IntKeyframe nextKeyframe = (IntKeyframe) mKeyframes.get(mNumKeyframes - 1);
int prevValue = prevKeyframe.getIntValue();
int nextValue = nextKeyframe.getIntValue();
float prevFraction = prevKeyframe.getFraction();
float nextFraction = nextKeyframe.getFraction();
final Interpolator interpolator = nextKeyframe.getInterpolator();
if (interpolator != null) {
fraction = interpolator.getInterpolation(fraction);
}
float intervalFraction = (fraction - prevFraction) / (nextFraction - prevFraction);
return mEvaluator == null
? prevValue + (int) (intervalFraction * (nextValue - prevValue)) :
mEvaluator.evaluate(intervalFraction, prevValue, nextValue).intValue();
}
IntKeyframe prevKeyframe = (IntKeyframe) mKeyframes.get(0);
for (int i = 1; i < mNumKeyframes; ++i) {
IntKeyframe nextKeyframe = (IntKeyframe) mKeyframes.get(i);
if (fraction < nextKeyframe.getFraction()) {
final Interpolator interpolator = nextKeyframe.getInterpolator();
float intervalFraction = (fraction - prevKeyframe.getFraction())
/ (nextKeyframe.getFraction() - prevKeyframe.getFraction());
int prevValue = prevKeyframe.getIntValue();
int nextValue = nextKeyframe.getIntValue();
// Apply interpolator on the proportional duration.
if (interpolator != null) {
intervalFraction = interpolator.getInterpolation(intervalFraction);
}
return mEvaluator == null
? prevValue + Math.round(intervalFraction * (nextValue - prevValue))
: mEvaluator.evaluate(intervalFraction, prevValue, nextValue).intValue();
}
prevKeyframe = nextKeyframe;
}
// shouldn't get here
return mKeyframes.get(mNumKeyframes - 1).getValue().intValue();
}
@Override
public Class<Integer> getType() {
return Integer.class;
}
}