BounceInterpolator.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.FloatRange;
/**
* An interpolator where the change bounces at the end.
*/
public class BounceInterpolator implements Interpolator {
/**
* Creates a new instance of {@link BounceInterpolator}.
*/
public BounceInterpolator() {
}
private static float bounce(float t) {
return t * t * 8.0f;
}
@Override
@FloatRange(from = 0, to = 1)
public float getInterpolation(@FloatRange(from = 0, to = 1) float input) {
// _b(t) = t * t * 8
// bs(t) = _b(t) for t < 0.3535
// bs(t) = _b(t - 0.54719) + 0.7 for t < 0.7408
// bs(t) = _b(t - 0.8526) + 0.9 for t < 0.9644
// bs(t) = _b(t - 1.0435) + 0.95 for t <= 1.0
// b(t) = bs(t * 1.1226)
float t = 1.1226f * input;
if (t < 0.3535f) {
return bounce(t);
} else if (t < 0.7408f) {
return bounce(t - 0.54719f) + 0.7f;
} else if (t < 0.9644f) {
return bounce(t - 0.8526f) + 0.9f;
} else {
return bounce(t - 1.0435f) + 0.95f;
}
}
}