| /* |
| * Copyright (C) 2010 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; |
| |
| /** |
| * Interface for use with the {@link ValueAnimator#setEvaluator(TypeEvaluator)} function. Evaluators |
| * allow developers to create animations on arbitrary property types, by allowing them to supply |
| * custom evaluators for types that are not automatically understood and used by the animation |
| * system. |
| * |
| * @see ValueAnimator#setEvaluator(TypeEvaluator) |
| */ |
| public interface TypeEvaluator<T> { |
| |
| /** |
| * This function returns the result of linearly interpolating the start and end values, with |
| * <code>fraction</code> representing the proportion between the start and end values. The |
| * calculation is a simple parametric calculation: <code>result = x0 + t * (x1 - x0)</code>, |
| * where <code>x0</code> is <code>startValue</code>, <code>x1</code> is <code>endValue</code>, |
| * and <code>t</code> is <code>fraction</code>. |
| * |
| * @param fraction The fraction from the starting to the ending values |
| * @param startValue The start value. |
| * @param endValue The end value. |
| * @return A linear interpolation between the start and end values, given the |
| * <code>fraction</code> parameter. |
| */ |
| public T evaluate(float fraction, T startValue, T endValue); |
| |
| } |