18b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru/* 28b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * Copyright (C) 2009 The Android Open Source Project 38b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * 48b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * Licensed under the Apache License, Version 2.0 (the "License"); 58b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * you may not use this file except in compliance with the License. 68b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * You may obtain a copy of the License at 78b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * 88b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * http://www.apache.org/licenses/LICENSE-2.0 98b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * 108b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * Unless required by applicable law or agreed to in writing, software 118b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * distributed under the License is distributed on an "AS IS" BASIS, 128b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 138b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * See the License for the specific language governing permissions and 148b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * limitations under the License. 158b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru */ 168b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 178b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Querupackage android.view.animation; 188b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 198b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queruimport android.content.Context; 208b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queruimport android.content.res.TypedArray; 218b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queruimport android.util.AttributeSet; 228b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 238b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru/** 248b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * An interpolator where the change starts backward then flings forward. 258b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru */ 268b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Querupublic class AnticipateInterpolator implements Interpolator { 278b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru private final float mTension; 288b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 298b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public AnticipateInterpolator() { 308b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = 2.0f; 318b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 328b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 338b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru /** 348b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * @param tension Amount of anticipation. When tension equals 0.0f, there is 358b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * no anticipation and the interpolator becomes a simple 368b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * acceleration interpolator. 378b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru */ 388b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public AnticipateInterpolator(float tension) { 398b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = tension; 408b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 418b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 428b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public AnticipateInterpolator(Context context, AttributeSet attrs) { 438b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru TypedArray a = context.obtainStyledAttributes(attrs, 448b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru com.android.internal.R.styleable.AnticipateInterpolator); 458b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 468b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = 478b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru a.getFloat(com.android.internal.R.styleable.AnticipateInterpolator_tension, 2.0f); 488b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 498b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru a.recycle(); 508b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 518b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 528b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public float getInterpolation(float t) { 538b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru // a(t) = t * t * ((tension + 1) * t - tension) 548b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru return t * t * ((mTension + 1) * t - mTension); 558b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 568b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru} 57