/*
* $RCSfile: ConvolveDescriptor.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:57:32 $
* $State: Exp $
*/
package com.lightcrafts.mediax.jai.operator;
import com.lightcrafts.media.jai.util.AreaOpPropertyGenerator;
import java.awt.RenderingHints;
import java.awt.image.RenderedImage;
import com.lightcrafts.mediax.jai.JAI;
import com.lightcrafts.mediax.jai.KernelJAI;
import com.lightcrafts.mediax.jai.OperationDescriptorImpl;
import com.lightcrafts.mediax.jai.ParameterBlockJAI;
import com.lightcrafts.mediax.jai.PropertyGenerator;
import com.lightcrafts.mediax.jai.RenderedOp;
import com.lightcrafts.mediax.jai.registry.RenderedRegistryMode;
/**
* An <code>OperationDescriptor</code> describing the "Convolve" operation.
*
* <p> Convolution is a spatial operation that computes each output
* sample by multiplying elements of a kernel with the samples
* surrounding a particular source sample.
*
* <p> For each destination sample, the kernel is rotated 180 degrees
* and its "key element," or origin, is placed over the source pixel
* corresponding with the destination pixel. The kernel elements are
* multiplied with the source pixels beneath them, and the resulting
* products are summed together to produce the destination sample
* value.
*
* <p> Pseudocode for the convolution operation on a single sample
* dst[x][y] is as follows, assuming the kernel is of size width x height
* and has already been rotated through 180 degrees. The kernel's Origin
* element is located at position (xOrigin, yOrigin):
*
* <pre>
* dst[x][y] = 0;
* for (int i = -xOrigin; i < -xOrigin + width; i++) {
* for (int j = -yOrigin; j < -yOrigin + height; j++) {
* dst[x][y] += src[x + i][y + j]*kernel[xOrigin + i][yOrigin + j];
* }
* }
* </pre>
*
* <p> Convolution, like any neighborhood operation, leaves a band of
* pixels around the edges undefined. For example, for a 3x3 kernel
* only four kernel elements and four source pixels contribute to the
* convolution pixel at the corners of the source image. Pixels that
* do not allow the full kernel to be applied to the source are not
* included in the destination image. A "Border" operation may be used
* to add an appropriate border to the source image in order to avoid
* shrinkage of the image boundaries.
*
* <p> The kernel may not be bigger in any dimension than the image data.
*
* It should be noted that this operation automatically adds a
* value of <code>Boolean.TRUE</code> for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> to the given
* <code>configuration</code> so that the operation is performed
* on the pixel values instead of being performed on the indices into
* the color map if the source(s) have an <code>IndexColorModel</code>.
* This addition will take place only if a value for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> has not already been
* provided by the user. Note that the <code>configuration</code> Map
* is cloned before the new hint is added to it. The operation can be
* smart about the value of the <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code>
* <code>RenderingHints</code>, i.e. while the default value for the
* <code>JAI.KEY_REPLACE_INDEX_COLOR_MODEL</code> is
* <code>Boolean.TRUE</code>, in some cases the operator could set the
* default.
*
* <p><table border=1>
* <caption>Resource List</caption>
* <tr><th>Name</th> <th>Value</th></tr>
* <tr><td>GlobalName</td> <td>Convolve</td></tr>
* <tr><td>LocalName</td> <td>Convolve</td></tr>
* <tr><td>Vendor</td> <td>com.lightcrafts.media.jai</td></tr>
* <tr><td>Description</td> <td>Performs kernel-based convolution
* on an image.</td></tr>
* <tr><td>DocURL</td> <td>http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ConvolveDescriptor.html</td></tr>
* <tr><td>Version</td> <td>1.0</td></tr>
* <tr><td>arg0Desc</td> <td>The convolution kernel.</td></tr>
* </table></p>
*
* <p><table border=1>
* <caption>Parameter List</caption>
* <tr><th>Name</th> <th>Class Type</th>
* <th>Default Value</th></tr>
* <tr><td>kernel</td> <td>com.lightcrafts.mediax.jai.KernelJAI</td>
* <td>NO_PARAMETER_DEFAULT</td>
* </table></p>
*
* @see com.lightcrafts.mediax.jai.OperationDescriptor
* @see com.lightcrafts.mediax.jai.KernelJAI
*/
public class ConvolveDescriptor extends OperationDescriptorImpl {
/**
* The resource strings that provide the general documentation and
* specify the parameter list for a Convolve operation.
*/
private static final String[][] resources = {
{"GlobalName", "Convolve"},
{"LocalName", "Convolve"},
{"Vendor", "com.lightcrafts.media.jai"},
{"Description", JaiI18N.getString("ConvolveDescriptor0")},
{"DocURL", "http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ConvolveDescriptor.html"},
{"Version", JaiI18N.getString("DescriptorVersion")},
{"arg0Desc", JaiI18N.getString("ConvolveDescriptor1")}
};
/** The parameter names for the Convolve operation. */
private static final String[] paramNames = {
"kernel"
};
/** The parameter class types for the Convolve operation. */
private static final Class[] paramClasses = {
com.lightcrafts.mediax.jai.KernelJAI.class
};
/** The parameter default values for the Convolve operation. */
private static final Object[] paramDefaults = {
NO_PARAMETER_DEFAULT
};
/** Constructor. */
public ConvolveDescriptor() {
super(resources, 1, paramClasses, paramNames, paramDefaults);
}
/**
* Returns an array of <code>PropertyGenerators</code> implementing
* property inheritance for the "Convolve" operation.
*
* @return An array of property generators.
*/
public PropertyGenerator[] getPropertyGenerators() {
PropertyGenerator[] pg = new PropertyGenerator[1];
pg[0] = new AreaOpPropertyGenerator();
return pg;
}
/**
* Performs kernel-based convolution on an image.
*
* <p>Creates a <code>ParameterBlockJAI</code> from all
* supplied arguments except <code>hints</code> and invokes
* {@link JAI#create(String,ParameterBlock,RenderingHints)}.
*
* @see JAI
* @see ParameterBlockJAI
* @see RenderedOp
*
* @param source0 <code>RenderedImage</code> source 0.
* @param kernel The convolution kernel.
* @param hints The <code>RenderingHints</code> to use.
* May be <code>null</code>.
* @return The <code>RenderedOp</code> destination.
* @throws IllegalArgumentException if <code>source0</code> is <code>null</code>.
* @throws IllegalArgumentException if <code>kernel</code> is <code>null</code>.
*/
public static RenderedOp create(RenderedImage source0,
KernelJAI kernel,
RenderingHints hints) {
ParameterBlockJAI pb =
new ParameterBlockJAI("Convolve",
RenderedRegistryMode.MODE_NAME);
pb.setSource("source0", source0);
pb.setParameter("kernel", kernel);
return JAI.create("Convolve", pb, hints);
}
}