1/* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License 15 */ 16 17package com.android.internal.graphics; 18 19import android.graphics.Color; 20import android.support.test.filters.SmallTest; 21 22import org.junit.Test; 23 24import static org.junit.Assert.assertTrue; 25 26@SmallTest 27public class ColorUtilsTest { 28 29 @Test 30 public void calculateMinimumBackgroundAlpha_satisfiestContrast() { 31 32 int alpha = ColorUtils.calculateMinimumBackgroundAlpha(Color.WHITE, Color.BLACK, 4.5f); 33 assertTrue("Alpha doesn't need to be 255 to satisfy contrast", alpha < 255); 34 35 int worstCase = ColorUtils.blendARGB(Color.WHITE, Color.BLACK, alpha/255f); 36 worstCase = ColorUtils.setAlphaComponent(worstCase, 255); 37 double contrast = ColorUtils.calculateContrast(Color.WHITE, worstCase); 38 assertTrue("Blended color should satisfy contrast", contrast >= 4.5); 39 40 } 41} 42