OvershootInterpolator.java revision c8ac775659fd252ce2cc9a61837c170ff70f0a1a
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 23c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reckimport com.android.internal.view.animation.HasNativeInterpolator; 24c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reckimport com.android.internal.view.animation.NativeInterpolatorFactory; 25c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reckimport com.android.internal.view.animation.NativeInterpolatorFactoryHelper; 26c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck 278b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru/** 288b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * An interpolator where the change flings forward and overshoots the last value 298b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * then comes back. 308b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru */ 31c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck@HasNativeInterpolator 32c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reckpublic class OvershootInterpolator implements Interpolator, NativeInterpolatorFactory { 338b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru private final float mTension; 348b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 358b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public OvershootInterpolator() { 368b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = 2.0f; 378b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 388b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 398b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru /** 408b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * @param tension Amount of overshoot. When tension equals 0.0f, there is 418b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * no overshoot and the interpolator becomes a simple 428b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru * deceleration interpolator. 438b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru */ 448b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public OvershootInterpolator(float tension) { 458b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = tension; 468b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 478b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 488b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public OvershootInterpolator(Context context, AttributeSet attrs) { 498b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru TypedArray a = context.obtainStyledAttributes(attrs, 508b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru com.android.internal.R.styleable.OvershootInterpolator); 518b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 528b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru mTension = 538b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru a.getFloat(com.android.internal.R.styleable.OvershootInterpolator_tension, 2.0f); 548b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 558b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru a.recycle(); 568b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 578b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru 588b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru public float getInterpolation(float t) { 598b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru // _o(t) = t * t * ((tension + 1) * t + tension) 608b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru // o(t) = _o(t - 1) + 1 618b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru t -= 1.0f; 628b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru return t * t * ((mTension + 1) * t + mTension) + 1.0f; 638b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru } 64c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck 65c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck /** @hide */ 66c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck @Override 67c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck public long createNativeInterpolator() { 68c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck return NativeInterpolatorFactoryHelper.createOvershootInterpolator(mTension); 69c8ac775659fd252ce2cc9a61837c170ff70f0a1aJohn Reck } 708b0662878eae69ab62e859b07165f086ea65cad5Jean-Baptiste Queru} 71