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