content: /*
   * Copyright (C) 2006 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 rate of change starts out slowly and
   * and then accelerates.
   *
   */
  @HasNativeInterpolator
  public class AccelerateInterpolator extends BaseInterpolator implements NativeInterpolatorFactory {
      private final float mFactor;
      private final double mDoubleFactor;
  
      public AccelerateInterpolator() {
          mFactor = 1.0f;
          mDoubleFactor = 2.0;
      }
  
      /**
       * Constructor
       *
       * @param factor Degree to which the animation should be eased. Seting
       *        factor to 1.0f produces a y=x^2 parabola. Increasing factor above
       *        1.0f  exaggerates the ease-in effect (i.e., it starts even
       *        slower and ends evens faster)
       */
      public AccelerateInterpolator(float factor) {
          mFactor = factor;
          mDoubleFactor = 2 * mFactor;
      }
  
      public AccelerateInterpolator(Context context, AttributeSet attrs) {
          this(context.getResources(), context.getTheme(), attrs);
      }
  
      /** @hide */
      public AccelerateInterpolator(Resources res, Theme theme, AttributeSet attrs) {
          TypedArray a;
          if (theme != null) {
              a = theme.obtainStyledAttributes(attrs, R.styleable.AccelerateInterpolator, 0, 0);
          } else {
              a = res.obtainAttributes(attrs, R.styleable.AccelerateInterpolator);
          }
  
          mFactor = a.getFloat(R.styleable.AccelerateInterpolator_factor, 1.0f);
          mDoubleFactor = 2 * mFactor;
          setChangingConfiguration(a.getChangingConfigurations());
          a.recycle();
      }
  
      public float getInterpolation(float input) {
          if (mFactor == 1.0f) {
              return input * input;
          } else {
              return (float)Math.pow(input, mDoubleFactor);
          }
      }
  
      /** @hide */
      @Override
      public long createNativeInterpolator() {
          return NativeInterpolatorFactoryHelper.createAccelerateInterpolator(mFactor);
      }
  }
  