/* * Copyright (C) 2016 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.support.transition; import android.animation.TypeEvaluator; import android.graphics.Rect; import android.support.annotation.RequiresApi; /** * This evaluator can be used to perform type interpolation between Rect values. */ @RequiresApi(14) class RectEvaluator implements TypeEvaluator { /** * When null, a new Rect is returned on every evaluate call. When non-null, * mRect will be modified and returned on every evaluate. */ private Rect mRect; /** * Construct a RectEvaluator that returns a new Rect on every evaluate call. * To avoid creating an object for each evaluate call, * {@link RectEvaluator#RectEvaluator(android.graphics.Rect)} should be used * whenever possible. */ RectEvaluator() { } /** * Constructs a RectEvaluator that modifies and returns reuseRect * in {@link #evaluate(float, android.graphics.Rect, android.graphics.Rect)} calls. * The value returned from * {@link #evaluate(float, android.graphics.Rect, android.graphics.Rect)} should * not be cached because it will change over time as the object is reused on each * call. * * @param reuseRect A Rect to be modified and returned by evaluate. */ RectEvaluator(Rect reuseRect) { mRect = reuseRect; } /** * This function returns the result of linearly interpolating the start and * end Rect values, with fraction representing the proportion * between the start and end values. The calculation is a simple parametric * calculation on each of the separate components in the Rect objects * (left, top, right, and bottom). * *

If {@link #RectEvaluator(android.graphics.Rect)} was used to construct * this RectEvaluator, the object returned will be the reuseRect * passed into the constructor.

* * @param fraction The fraction from the starting to the ending values * @param startValue The start Rect * @param endValue The end Rect * @return A linear interpolation between the start and end values, given the * fraction parameter. */ @Override public Rect evaluate(float fraction, Rect startValue, Rect endValue) { int left = startValue.left + (int) ((endValue.left - startValue.left) * fraction); int top = startValue.top + (int) ((endValue.top - startValue.top) * fraction); int right = startValue.right + (int) ((endValue.right - startValue.right) * fraction); int bottom = startValue.bottom + (int) ((endValue.bottom - startValue.bottom) * fraction); if (mRect == null) { return new Rect(left, top, right, bottom); } else { mRect.set(left, top, right, bottom); return mRect; } } }