1 /* 2 * Copyright (C) 2009 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.view.animation; 18 19 import android.content.Context; 20 import android.content.res.TypedArray; 21 import android.util.AttributeSet; 22 23 /** 24 * An interpolator where the change bounces at the end. 25 */ 26 public class BounceInterpolator implements Interpolator { BounceInterpolator()27 public BounceInterpolator() { 28 } 29 30 @SuppressWarnings({"UnusedDeclaration"}) BounceInterpolator(Context context, AttributeSet attrs)31 public BounceInterpolator(Context context, AttributeSet attrs) { 32 } 33 bounce(float t)34 private static float bounce(float t) { 35 return t * t * 8.0f; 36 } 37 getInterpolation(float t)38 public float getInterpolation(float t) { 39 // _b(t) = t * t * 8 40 // bs(t) = _b(t) for t < 0.3535 41 // bs(t) = _b(t - 0.54719) + 0.7 for t < 0.7408 42 // bs(t) = _b(t - 0.8526) + 0.9 for t < 0.9644 43 // bs(t) = _b(t - 1.0435) + 0.95 for t <= 1.0 44 // b(t) = bs(t * 1.1226) 45 t *= 1.1226f; 46 if (t < 0.3535f) return bounce(t); 47 else if (t < 0.7408f) return bounce(t - 0.54719f) + 0.7f; 48 else if (t < 0.9644f) return bounce(t - 0.8526f) + 0.9f; 49 else return bounce(t - 1.0435f) + 0.95f; 50 } 51 }