1 /* 2 * Copyright (C) 2014 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 com.android.server.policy; 18 19 import android.view.animation.Interpolator; 20 21 public class LogDecelerateInterpolator implements Interpolator { 22 23 private int mBase; 24 private int mDrift; 25 private final float mLogScale; 26 27 public LogDecelerateInterpolator(int base, int drift) { 28 mBase = base; 29 mDrift = drift; 30 31 mLogScale = 1f / computeLog(1, mBase, mDrift); 32 } 33 34 private static float computeLog(float t, int base, int drift) { 35 return (float) -Math.pow(base, -t) + 1 + (drift * t); 36 } 37 38 @Override 39 public float getInterpolation(float t) { 40 return computeLog(t, mBase, mDrift) * mLogScale; 41 } 42 } 43
