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