1 /* Copyright (C) 2005-2011 Fabio Riccardi */ 2 3 /* 4 * $RCSfile: ConvolveDescriptor.java,v $ 5 * 6 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved. 7 * 8 * Use is subject to license terms. 9 * 10 * $Revision: 1.1 $ 11 * $Date: 2005/02/11 04:57:32 $ 12 * $State: Exp $ 13 */ 14 package com.lightcrafts.jai.operator; 15 16 import com.lightcrafts.media.jai.util.AreaOpPropertyGenerator; 17 import java.awt.RenderingHints; 18 import java.awt.image.RenderedImage; 19 import com.lightcrafts.mediax.jai.JAI; 20 import com.lightcrafts.mediax.jai.KernelJAI; 21 import com.lightcrafts.mediax.jai.OperationDescriptorImpl; 22 import com.lightcrafts.mediax.jai.ParameterBlockJAI; 23 import com.lightcrafts.mediax.jai.PropertyGenerator; 24 import com.lightcrafts.mediax.jai.RenderedOp; 25 import com.lightcrafts.mediax.jai.registry.RenderedRegistryMode; 26 27 /** 28 * An <code>OperationDescriptor</code> describing the "Convolve" operation. 29 * 30 * <p> Convolution is a spatial operation that computes each output 31 * sample by multiplying elements of a kernel with the samples 32 * surrounding a particular source sample. 33 * 34 * <p> For each destination sample, the kernel is rotated 180 degrees 35 * and its "key element," or origin, is placed over the source pixel 36 * corresponding with the destination pixel. The kernel elements are 37 * multiplied with the source pixels beneath them, and the resulting 38 * products are summed together to produce the destination sample 39 * value. 40 * 41 * <p> Pseudocode for the convolution operation on a single sample 42 * dst[x][y] is as follows, assuming the kernel is of size width x height 43 * and has already been rotated through 180 degrees. The kernel's Origin 44 * element is located at position (xOrigin, yOrigin): 45 * 46 * <pre> 47 * dst[x][y] = 0; 48 * for (int i = -xOrigin; i < -xOrigin + width; i++) { 49 * for (int j = -yOrigin; j < -yOrigin + height; j++) { 50 * dst[x][y] += src[x + i][y + j]*kernel[xOrigin + i][yOrigin + j]; 51 * } 52 * } 53 * </pre> 54 * 55 * <p> Convolution, like any neighborhood operation, leaves a band of 56 * pixels around the edges undefined. For example, for a 3x3 kernel 57 * only four kernel elements and four source pixels contribute to the 58 * convolution pixel at the corners of the source image. Pixels that 59 * do not allow the full kernel to be applied to the source are not 60 * included in the destination image. A "Border" operation may be used 61 * to add an appropriate border to the source image in order to avoid 62 * shrinkage of the image boundaries. 63 * 64 * <p> The kernel may not be bigger in any dimension than the image data. 65 * 66 * It should be noted that this operation automatically adds a 67 * value of <code>Boolean.TRUE</code> for the 68 * <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> to the given 69 * <code>configuration</code> so that the operation is performed 70 * on the pixel values instead of being performed on the indices into 71 * the color map if the source(s) have an <code>IndexColorModel</code>. 72 * This addition will take place only if a value for the 73 * <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> has not already been 74 * provided by the user. Note that the <code>configuration</code> Map 75 * is cloned before the new hint is added to it. The operation can be 76 * smart about the value of the <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> 77 * <code>RenderingHints</code>, i.e. while the default value for the 78 * <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> is 79 * <code>Boolean.TRUE</code>, in some cases the operator could set the 80 * default. 81 * 82 * <p><table border=1> 83 * <caption>Resource List</caption> 84 * <tr><th>Name</th> <th>Value</th></tr> 85 * <tr><td>GlobalName</td> <td>Convolve</td></tr> 86 * <tr><td>LocalName</td> <td>Convolve</td></tr> 87 * <tr><td>Vendor</td> <td>com.lightcrafts.media.jai</td></tr> 88 * <tr><td>Description</td> <td>Performs kernel-based convolution 89 * on an image.</td></tr> 90 * <tr><td>DocURL</td> <td>http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ConvolveDescriptor.html</td></tr> 91 * <tr><td>Version</td> <td>1.0</td></tr> 92 * <tr><td>arg0Desc</td> <td>The convolution kernel.</td></tr> 93 * </table></p> 94 * 95 * <p><table border=1> 96 * <caption>Parameter List</caption> 97 * <tr><th>Name</th> <th>Class Type</th> 98 * <th>Default Value</th></tr> 99 * <tr><td>kernel</td> <td>com.lightcrafts.mediax.jai.KernelJAI</td> 100 * <td>NO_PARAMETER_DEFAULT</td> 101 * </table></p> 102 * 103 * @see com.lightcrafts.mediax.jai.OperationDescriptor 104 * @see com.lightcrafts.mediax.jai.KernelJAI 105 */ 106 public class LCSeparableConvolveDescriptor extends OperationDescriptorImpl { 107 108 /** 109 * The resource strings that provide the general documentation and 110 * specify the parameter list for a Convolve operation. 111 */ 112 private static final String[][] resources = { 113 {"GlobalName", "LCSeparableConvolve"}, 114 {"LocalName", "LCSeparableConvolve"}, 115 {"Vendor", "com.lightcrafts.jai"}, 116 {"Description", "Fast Convolution for Separable Kernels"}, 117 {"DocURL", "http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ConvolveDescriptor.html"}, 118 {"Version", "1.0"}, 119 {"arg0Desc", "an image..."} 120 }; 121 122 /** The parameter names for the Convolve operation. */ 123 private static final String[] paramNames = { 124 "kernel" 125 }; 126 127 /** The parameter class types for the Convolve operation. */ 128 private static final Class[] paramClasses = { 129 com.lightcrafts.mediax.jai.KernelJAI.class 130 }; 131 132 /** The parameter default values for the Convolve operation. */ 133 private static final Object[] paramDefaults = { 134 NO_PARAMETER_DEFAULT 135 }; 136 137 /** Constructor. */ LCSeparableConvolveDescriptor()138 public LCSeparableConvolveDescriptor() { 139 super(resources, 1, paramClasses, paramNames, paramDefaults); 140 } 141 142 /** 143 * Returns an array of <code>PropertyGenerators</code> implementing 144 * property inheritance for the "Convolve" operation. 145 * 146 * @return An array of property generators. 147 */ getPropertyGenerators()148 public PropertyGenerator[] getPropertyGenerators() { 149 PropertyGenerator[] pg = new PropertyGenerator[1]; 150 pg[0] = new AreaOpPropertyGenerator(); 151 return pg; 152 } 153 154 155 /** 156 * Performs kernel-based convolution on an image. 157 * 158 * <p>Creates a <code>ParameterBlockJAI</code> from all 159 * supplied arguments except <code>hints</code> and invokes 160 * {@link JAI#create(String,java.awt.image.renderable.ParameterBlock,RenderingHints)}. 161 * 162 * @see JAI 163 * @see ParameterBlockJAI 164 * @see RenderedOp 165 * 166 * @param source0 <code>RenderedImage</code> source 0. 167 * @param kernel The convolution kernel. 168 * @param hints The <code>RenderingHints</code> to use. 169 * May be <code>null</code>. 170 * @return The <code>RenderedOp</code> destination. 171 * @throws IllegalArgumentException if <code>source0</code> is <code>null</code>. 172 * @throws IllegalArgumentException if <code>kernel</code> is <code>null</code>. 173 */ create(RenderedImage source0, KernelJAI kernel, RenderingHints hints)174 public static RenderedOp create(RenderedImage source0, 175 KernelJAI kernel, 176 RenderingHints hints) { 177 ParameterBlockJAI pb = 178 new ParameterBlockJAI("LCSeparableConvolve", 179 RenderedRegistryMode.MODE_NAME); 180 181 pb.setSource("source0", source0); 182 183 pb.setParameter("kernel", kernel); 184 185 return JAI.create("LCSeparableConvolve", pb, hints); 186 } 187 } 188