| /* |
| * Copyright (C) 2013 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.animation; |
| |
| /** |
| * This evaluator can be used to perform type interpolation between <code>float[]</code> values. |
| * Each index into the array is treated as a separate value to interpolate. For example, |
| * evaluating <code>{100, 200}</code> and <code>{300, 400}</code> will interpolate the value at |
| * the first index between 100 and 300 and the value at the second index value between 200 and 400. |
| */ |
| public class FloatArrayEvaluator implements TypeEvaluator<float[]> { |
| |
| private float[] mArray; |
| |
| /** |
| * Create a FloatArrayEvaluator that does not reuse the animated value. Care must be taken |
| * when using this option because on every evaluation a new <code>float[]</code> will be |
| * allocated. |
| * |
| * @see #FloatArrayEvaluator(float[]) |
| */ |
| public FloatArrayEvaluator() { |
| } |
| |
| /** |
| * Create a FloatArrayEvaluator that reuses <code>reuseArray</code> for every evaluate() call. |
| * Caution must be taken to ensure that the value returned from |
| * {@link android.animation.ValueAnimator#getAnimatedValue()} is not cached, modified, or |
| * used across threads. The value will be modified on each <code>evaluate()</code> call. |
| * |
| * @param reuseArray The array to modify and return from <code>evaluate</code>. |
| */ |
| public FloatArrayEvaluator(float[] reuseArray) { |
| mArray = reuseArray; |
| } |
| |
| /** |
| * Interpolates the value at each index by the fraction. If |
| * {@link #FloatArrayEvaluator(float[])} was used to construct this object, |
| * <code>reuseArray</code> will be returned, otherwise a new <code>float[]</code> |
| * will be returned. |
| * |
| * @param fraction The fraction from the starting to the ending values |
| * @param startValue The start value. |
| * @param endValue The end value. |
| * @return A <code>float[]</code> where each element is an interpolation between |
| * the same index in startValue and endValue. |
| */ |
| @Override |
| public float[] evaluate(float fraction, float[] startValue, float[] endValue) { |
| float[] array = mArray; |
| if (array == null) { |
| array = new float[startValue.length]; |
| } |
| |
| for (int i = 0; i < array.length; i++) { |
| float start = startValue[i]; |
| float end = endValue[i]; |
| array[i] = start + (fraction * (end - start)); |
| } |
| return array; |
| } |
| } |