Here you can find the source of darkerColor(Color c, double amount)
public static Color darkerColor(Color c, double amount)
//package com.java2s; /******************************************************************************* * Breakout Cave Survey Visualizer//from w w w.j av a2s. c o m * * Copyright (C) 2014 James Edwards * * jedwards8 at fastmail dot fm * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program 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 for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *******************************************************************************/ import java.awt.Color; public class Main { public static Color darkerColor(Color c, double amount) { float[] hsbvals = new float[3]; Color.RGBtoHSB(c.getRed(), c.getGreen(), c.getBlue(), hsbvals); hsbvals[2] = Math.min(1f, Math.max(0f, (float) (hsbvals[2] - amount))); int rgb = Color.HSBtoRGB(hsbvals[0], hsbvals[1], hsbvals[2]); rgb |= c.getAlpha() << 24; return new Color(rgb, true); } }