content: /*
   * 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 extends BaseInterpolator implements 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);
          setChangingConfiguration(a.getChangingConfigurations());
          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);
      }
  }
  