| /* |
| * Copyright (C) 2009 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.view.animation; |
| |
| import android.content.Context; |
| import android.content.res.Resources; |
| import android.content.res.Resources.Theme; |
| import android.content.res.TypedArray; |
| import android.util.AttributeSet; |
| |
| import com.android.internal.R; |
| import com.android.internal.view.animation.HasNativeInterpolator; |
| import com.android.internal.view.animation.NativeInterpolatorFactory; |
| import com.android.internal.view.animation.NativeInterpolatorFactoryHelper; |
| |
| /** |
| * An interpolator where the change flings forward and overshoots the last value |
| * then comes back. |
| */ |
| @HasNativeInterpolator |
| public class OvershootInterpolator implements Interpolator, NativeInterpolatorFactory { |
| private final float mTension; |
| |
| public OvershootInterpolator() { |
| mTension = 2.0f; |
| } |
| |
| /** |
| * @param tension Amount of overshoot. When tension equals 0.0f, there is |
| * no overshoot and the interpolator becomes a simple |
| * deceleration interpolator. |
| */ |
| public OvershootInterpolator(float tension) { |
| mTension = tension; |
| } |
| |
| public OvershootInterpolator(Context context, AttributeSet attrs) { |
| this(context.getResources(), context.getTheme(), attrs); |
| } |
| |
| /** @hide */ |
| public OvershootInterpolator(Resources res, Theme theme, AttributeSet attrs) { |
| TypedArray a; |
| if (theme != null) { |
| a = theme.obtainStyledAttributes(attrs, R.styleable.OvershootInterpolator, 0, 0); |
| } else { |
| a = res.obtainAttributes(attrs, R.styleable.OvershootInterpolator); |
| } |
| |
| mTension = |
| a.getFloat(R.styleable.OvershootInterpolator_tension, 2.0f); |
| |
| a.recycle(); |
| } |
| |
| public float getInterpolation(float t) { |
| // _o(t) = t * t * ((tension + 1) * t + tension) |
| // o(t) = _o(t - 1) + 1 |
| t -= 1.0f; |
| return t * t * ((mTension + 1) * t + mTension) + 1.0f; |
| } |
| |
| /** @hide */ |
| @Override |
| public long createNativeInterpolator() { |
| return NativeInterpolatorFactoryHelper.createOvershootInterpolator(mTension); |
| } |
| } |