1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math3.userguide.genetics; 18 19 import java.awt.AlphaComposite; 20 import java.awt.Color; 21 import java.awt.Graphics2D; 22 import java.awt.RenderingHints; 23 import java.awt.image.BufferedImage; 24 import java.util.ArrayList; 25 import java.util.List; 26 27 import org.apache.commons.math3.genetics.AbstractListChromosome; 28 import org.apache.commons.math3.genetics.Chromosome; 29 import org.apache.commons.math3.genetics.InvalidRepresentationException; 30 31 /** 32 * A simple chromosome representing a list of polygons. 33 */ 34 public class PolygonChromosome extends AbstractListChromosome<Polygon> { 35 36 /** The reference image for fitness testing. */ 37 private static BufferedImage refImage; 38 /** The image buffer used to draw the current chromosome during fitness testing. */ 39 private static BufferedImage testImage; 40 setRefImage(BufferedImage ref)41 public static void setRefImage(BufferedImage ref) { 42 refImage = ref; 43 } 44 setTestImage(BufferedImage image)45 public static void setTestImage(BufferedImage image) { 46 testImage = image; 47 } 48 PolygonChromosome(List<Polygon> representation)49 public PolygonChromosome(List<Polygon> representation) { 50 super(representation); 51 } 52 53 @Override checkValidity(List<Polygon> chromosomeRepresentation)54 protected void checkValidity(List<Polygon> chromosomeRepresentation) throws InvalidRepresentationException { 55 // do nothing 56 } 57 58 @Override newFixedLengthChromosome(List<Polygon> chromosomeRepresentation)59 public AbstractListChromosome<Polygon> newFixedLengthChromosome(List<Polygon> chromosomeRepresentation) { 60 return new PolygonChromosome(chromosomeRepresentation); 61 } 62 63 /** 64 * Return the internal representation, which is needed for our custom mutation policy. 65 * 66 * @return the list of polygons 67 */ getPolygonRepresentation()68 public List<Polygon> getPolygonRepresentation() { 69 return getRepresentation(); 70 } 71 72 /** 73 * Calculate the fitness function for this chromosome. 74 * <p> 75 * For this purpose, we first draw the polygons on the test buffer, and 76 * then compare the resulting image pixel by pixel with the reference image. 77 */ fitness()78 public double fitness() { 79 80 Graphics2D g2 = testImage.createGraphics(); 81 82 int width = testImage.getWidth(); 83 int height = testImage.getHeight(); 84 85 draw(g2, width, height); 86 g2.dispose(); 87 88 int[] refPixels = refImage.getData().getPixels(0, 0, refImage.getWidth(), refImage.getHeight(), (int[]) null); 89 int[] testPixels = testImage.getData().getPixels(0, 0, testImage.getWidth(), testImage.getHeight(), (int[]) null); 90 91 int diff = 0; 92 int p = width * height * 4 - 1; // 4 channels: rgba 93 int idx = 0; 94 95 do { 96 if (idx++ % 4 != 0) { // ignore the alpha channel for fitness 97 int dp = testPixels[p] - refPixels[p]; 98 if (dp < 0) { 99 diff -= dp; 100 } else { 101 diff += dp; 102 } 103 } 104 } while(--p > 0); 105 106 return (1.0 - diff / (width * height * 3.0 * 256)); 107 } 108 draw(Graphics2D g, int width, int height)109 public void draw(Graphics2D g, int width, int height) { 110 g.setBackground(Color.WHITE); 111 g.clearRect(0, 0, width, height); 112 113 g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); 114 g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER)); 115 116 List<Polygon> polygons = getPolygonRepresentation(); 117 for (Polygon p : polygons) { 118 p.draw(g, width, height); 119 } 120 } 121 122 @Override toString()123 public String toString() { 124 return String.format("(f=%s)", getFitness()); 125 } 126 randomChromosome(int polygonLength, int polygonCount)127 public static Chromosome randomChromosome(int polygonLength, int polygonCount) { 128 List<Polygon> list = new ArrayList<Polygon>(polygonCount); 129 for (int j = 0; j < polygonCount; j++) { 130 list.add(Polygon.randomPolygon(polygonLength)); 131 } 132 return new PolygonChromosome(list); 133 } 134 135 } 136