1 /* 2 * Copyright (C) 2007 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.util.AttributeSet; 21 22 import com.android.internal.view.animation.HasNativeInterpolator; 23 import com.android.internal.view.animation.NativeInterpolatorFactory; 24 import com.android.internal.view.animation.NativeInterpolatorFactoryHelper; 25 26 /** 27 * An interpolator where the rate of change starts and ends slowly but 28 * accelerates through the middle. 29 */ 30 @HasNativeInterpolator 31 public class AccelerateDecelerateInterpolator extends BaseInterpolator 32 implements NativeInterpolatorFactory { AccelerateDecelerateInterpolator()33 public AccelerateDecelerateInterpolator() { 34 } 35 36 @SuppressWarnings({"UnusedDeclaration"}) AccelerateDecelerateInterpolator(Context context, AttributeSet attrs)37 public AccelerateDecelerateInterpolator(Context context, AttributeSet attrs) { 38 } 39 getInterpolation(float input)40 public float getInterpolation(float input) { 41 return (float)(Math.cos((input + 1) * Math.PI) / 2.0f) + 0.5f; 42 } 43 44 /** @hide */ 45 @Override createNativeInterpolator()46 public long createNativeInterpolator() { 47 return NativeInterpolatorFactoryHelper.createAccelerateDecelerateInterpolator(); 48 } 49 } 50