Here you can find the source of setColorBrightness(Color c, double y)
private static Color setColorBrightness(Color c, double y)
//package com.java2s; /*/* www. j a v a2 s.c o m*/ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ import java.awt.*; import static java.lang.Math.*; public class Main { private static Color setColorBrightness(Color c, double y) { // Convert YIQ -> RGB double i = (c.getRed() * 0.596 - c.getGreen() * 0.275 - c.getBlue() * 0.321); double q = (c.getRed() * 0.212 - c.getGreen() * 0.523 + c.getBlue() * 0.311); // Keep values in legal range. This may reduce the // achieved contrast somewhat. int r = max(0, min(255, (int) round(y + i * 0.956 + q * 0.621))); int g = max(0, min(255, (int) round(y - i * 0.272 - q * 0.647))); int b = max(0, min(255, (int) round(y - i * 1.105 + q * 1.702))); return new Color(r, g, b); } }