Here you can find the source of getDarker(Color c)
public static Color getDarker(Color c)
//package com.java2s; /*/*ww w .j av a 2s. c om*/ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright 1997-2010 Oracle and/or its affiliates. All rights reserved. * * Oracle and Java are registered trademarks of Oracle and/or its affiliates. * Other names may be trademarks of their respective owners. * * The contents of this file are subject to the terms of either the GNU * General Public License Version 2 only ("GPL") or the Common * Development and Distribution License("CDDL") (collectively, the * "License"). You may not use this file except in compliance with the * License. You can obtain a copy of the License at * http://www.netbeans.org/cddl-gplv2.html * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the * specific language governing permissions and limitations under the * License. When distributing the software, include this License Header * Notice in each file and include the License file at * nbbuild/licenses/CDDL-GPL-2-CP. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the GPL Version 2 section of the License file that * accompanied this code. If applicable, add the following below the * License Header, with the fields enclosed by brackets [] replaced by * your own identifying information: * "Portions Copyrighted [year] [name of copyright owner]" * * Contributor(s): * The Original Software is NetBeans. The Initial Developer of the Original * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun * Microsystems, Inc. All Rights Reserved. * * If you wish your version of this file to be governed by only the CDDL * or only the GPL Version 2, indicate your decision by adding * "[Contributor] elects to include this software in this distribution * under the [CDDL or GPL Version 2] license." If you do not indicate a * single choice of license, a recipient has the option to distribute * your version of this file under either the CDDL, the GPL Version 2 or * to extend the choice of license to its licensees as provided above. * However, if you add GPL Version 2 code and therefore, elected the GPL * Version 2 license, then the option applies only if the new code is * made subject to such option by the copyright holder. */ import java.awt.*; import java.util.HashMap; import java.util.Map; public class Main { public static final float ALTERNATE_ROW_DARKER_FACTOR = 0.96f; private static Map<Integer, Color> DARKER_CACHE; public static Color getDarker(Color c) { if (DARKER_CACHE == null) DARKER_CACHE = new HashMap(); int rgb = c.getRGB(); Color d = DARKER_CACHE.get(rgb); if (d == null) { if (c.equals(Color.WHITE)) { d = new Color(244, 244, 244); } else { d = getSafeColor((int) (c.getRed() * ALTERNATE_ROW_DARKER_FACTOR), (int) (c.getGreen() * ALTERNATE_ROW_DARKER_FACTOR), (int) (c.getBlue() * ALTERNATE_ROW_DARKER_FACTOR)); } DARKER_CACHE.put(rgb, d); } return d; } public static Color getSafeColor(int red, int green, int blue) { red = Math.max(red, 0); red = Math.min(red, 255); green = Math.max(green, 0); green = Math.min(green, 255); blue = Math.max(blue, 0); blue = Math.min(blue, 255); return new Color(red, green, blue); } }