Java tutorial
/* * This code is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */ //package no.geosoft.cc.color.ui; import java.awt.Color; /** * Common color utilities. * * @author <a href="mailto:jacob.dreyer@geosoft.no">Jacob Dreyer</a> */ public class ColorUtil { /** * Blend two colors. * * @param color1 First color to blend. * @param color2 Second color to blend. * @param ratio Blend ratio. 0.5 will give even blend, 1.0 will return * color1, 0.0 will return color2 and so on. * @return Blended color. */ public static Color blend(Color color1, Color color2, double ratio) { float r = (float) ratio; float ir = (float) 1.0 - r; float rgb1[] = new float[3]; float rgb2[] = new float[3]; color1.getColorComponents(rgb1); color2.getColorComponents(rgb2); Color color = new Color(rgb1[0] * r + rgb2[0] * ir, rgb1[1] * r + rgb2[1] * ir, rgb1[2] * r + rgb2[2] * ir); return color; } /** * Make an even blend between two colors. * * @param c1 First color to blend. * @param c2 Second color to blend. * @return Blended color. */ public static Color blend(Color color1, Color color2) { return ColorUtil.blend(color1, color2, 0.5); } /** * Make a color darker. * * @param color Color to make darker. * @param fraction Darkness fraction. * @return Darker color. */ public static Color darker(Color color, double fraction) { int red = (int) Math.round(color.getRed() * (1.0 - fraction)); int green = (int) Math.round(color.getGreen() * (1.0 - fraction)); int blue = (int) Math.round(color.getBlue() * (1.0 - fraction)); if (red < 0) red = 0; else if (red > 255) red = 255; if (green < 0) green = 0; else if (green > 255) green = 255; if (blue < 0) blue = 0; else if (blue > 255) blue = 255; int alpha = color.getAlpha(); return new Color(red, green, blue, alpha); } /** * Make a color lighter. * * @param color Color to make lighter. * @param fraction Darkness fraction. * @return Lighter color. */ public static Color lighter(Color color, double fraction) { int red = (int) Math.round(color.getRed() * (1.0 + fraction)); int green = (int) Math.round(color.getGreen() * (1.0 + fraction)); int blue = (int) Math.round(color.getBlue() * (1.0 + fraction)); if (red < 0) red = 0; else if (red > 255) red = 255; if (green < 0) green = 0; else if (green > 255) green = 255; if (blue < 0) blue = 0; else if (blue > 255) blue = 255; int alpha = color.getAlpha(); return new Color(red, green, blue, alpha); } /** * Return the hex name of a specified color. * * @param color Color to get hex name of. * @return Hex name of color: "rrggbb". */ public static String getHexName(Color color) { int r = color.getRed(); int g = color.getGreen(); int b = color.getBlue(); String rHex = Integer.toString(r, 16); String gHex = Integer.toString(g, 16); String bHex = Integer.toString(b, 16); return (rHex.length() == 2 ? "" + rHex : "0" + rHex) + (gHex.length() == 2 ? "" + gHex : "0" + gHex) + (bHex.length() == 2 ? "" + bHex : "0" + bHex); } /** * Return the "distance" between two colors. The rgb entries are taken * to be coordinates in a 3D space [0.0-1.0], and this method returnes * the distance between the coordinates for the first and second color. * * @param r1, g1, b1 First color. * @param r2, g2, b2 Second color. * @return Distance bwetween colors. */ public static double colorDistance(double r1, double g1, double b1, double r2, double g2, double b2) { double a = r2 - r1; double b = g2 - g1; double c = b2 - b1; return Math.sqrt(a * a + b * b + c * c); } /** * Return the "distance" between two colors. * * @param color1 First color [r,g,b]. * @param color2 Second color [r,g,b]. * @return Distance bwetween colors. */ public static double colorDistance(double[] color1, double[] color2) { return ColorUtil.colorDistance(color1[0], color1[1], color1[2], color2[0], color2[1], color2[2]); } /** * Return the "distance" between two colors. * * @param color1 First color. * @param color2 Second color. * @return Distance between colors. */ public static double colorDistance(Color color1, Color color2) { float rgb1[] = new float[3]; float rgb2[] = new float[3]; color1.getColorComponents(rgb1); color2.getColorComponents(rgb2); return ColorUtil.colorDistance(rgb1[0], rgb1[1], rgb1[2], rgb2[0], rgb2[1], rgb2[2]); } /** * Check if a color is more dark than light. Useful if an entity of * this color is to be labeled: Use white label on a "dark" color and * black label on a "light" color. * * @param r,g,b Color to check. * @return True if this is a "dark" color, false otherwise. */ public static boolean isDark(double r, double g, double b) { // Measure distance to white and black respectively double dWhite = ColorUtil.colorDistance(r, g, b, 1.0, 1.0, 1.0); double dBlack = ColorUtil.colorDistance(r, g, b, 0.0, 0.0, 0.0); return dBlack < dWhite; } /** * Check if a color is more dark than light. Useful if an entity of * this color is to be labeled: Use white label on a "dark" color and * black label on a "light" color. * * @param color Color to check. * @return True if this is a "dark" color, false otherwise. */ public static boolean isDark(Color color) { float r = color.getRed() / 255.0f; float g = color.getGreen() / 255.0f; float b = color.getBlue() / 255.0f; return isDark(r, g, b); } }