/*
* $RCSfile: ExtremaDescriptor.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:57:35 $
* $State: Exp $
*/
package com.lightcrafts.mediax.jai.operator;
import java.awt.RenderingHints;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.ParameterBlock;
import com.lightcrafts.mediax.jai.JAI;
import com.lightcrafts.mediax.jai.OperationDescriptorImpl;
import com.lightcrafts.mediax.jai.ParameterBlockJAI;
import com.lightcrafts.mediax.jai.ROI;
import com.lightcrafts.mediax.jai.RenderedOp;
import com.lightcrafts.mediax.jai.registry.RenderedRegistryMode;
/**
* An <code>OperationDescriptor</code> describing the "Extrema" operation.
*
* <p> The Extrema operation scans a specific region of a rendered
* image and finds the maximum and minimum pixel values for each band
* within that region of the image. The image data pass through this
* operation unchanged.
*
* <p> The region-wise maximum and minimum pixel values may be obtained
* as properties. Calling the <code>getProperty</code> method on this
* operation with "extrema" as the property name retrieves both the
* region-wise maximum and minimum pixel values. Calling it with
* "maximum" as the property name retrieves the region-wise maximum
* pixel value, and with "minimum" as the property name retrieves the
* region-wise minimum pixel value. The return value for "extrema" has
* type <code>double[2][#bands]</code>, and those for "maximum"
* and "minimum" have type <code>double[#bands]</code>.
*
* <p> The region of interest (ROI) does not have to be a rectangle.
* It may be <code>null</code>, in which case the entire image is
* scanned to find the image-wise maximum and minimum pixel values
* for each band.
*
* <p> The set of pixels scanned may be further reduced by
* specifying the "xPeriod" and "yPeriod" parameters that represent
* the sampling rate along each axis. These variables may not be
* less than 1. However, they may be <code>null</code>, in which
* case the sampling rate is set to 1; that is, every pixel in the
* ROI is processed.
*
* <p> The <code>Boolean</code> parameter "saveLocations" indicates whether
* the locations of the extrema will be computed. If <code>TRUE</code>, the
* locations are computed and stored in the properties "minLocations" and
* "maxLocations" in the form of lists of run length codes. Each run length
* code is stored as a three-entry integer array <code>(xStart, yStart,
* length)</code>. Because the statistics are implemented on the
* low-resolution image, this <code>length</code> is defined on the image
* coordinate system of the low-resolution image. Thus, the run length code
* above means the pixels <code>(xStart, yStart), (xStart + xPeriod, yStart),
* ..., (xStart + (length - 1) * xPeriod, yStart) </code> of the original
* image have a value of the maximum or minimum, depending on whether this
* run exists in the property "maxLocations" or "minLocations". The run length
* code is row-based, thus the run doesn't wrap on the image boundaries.
* Runs are not guaranteed to be maximal, e.g. a run that crosses tile
* boundaries might be broken at the boundary into multiple runs. The order
* of the runs is not guaranteed.
*
* <p> The value objects of the properties "minLocations" and "maxLocations"
* are arrays of <code>java.util.List</code>. Each array entry contains
* the minimum/maximum locations of one band. The elements in
* a list can be accessed using the iterator of
* the <code>java.util.List</code>. For example, the sample code below
* demonstrates how to retrieve the minimum locations of the first band:
* <pre>
* List minLocations = ((List[])extremaOp.getProperty("minLocations"))[0];
* Iterator iter = minLocations.iterator();
* while(iter.hasNext()) {
* int[] runLength = (int[])iter.next();
* int xStart = runLength[0];
* int yStart = runLength[1];
* int length = runLength[2];
* }
* </pre>
*
* <p> In the implementation of this operator, the proper use of the parameter
* "saveLocations" also helps to keep the efficiency of the operator in the
* common case: when only the extremal values are computed.
*
* <p> The parameter "maxRuns" is the maximum number of run length codes that
* the user would like to store. It is defined to reduce memory
* consumption on very large images. If the parameter "saveLocations" is
* <code>FALSE</code>, this parameter will be ignored. If this parameter is
* equal to <code> Integer.MAX_VALUE</code>, all the locations will be saved.
*
* <p><table border=1>
* <caption>Resource List</caption>
* <tr><th>Name</th> <th>Value</th></tr>
* <tr><td>GlobalName</td> <td>Extrema</td></tr>
* <tr><td>LocalName</td> <td>Extrema</td></tr>
* <tr><td>Vendor</td> <td>com.lightcrafts.media.jai</td></tr>
* <tr><td>Description</td> <td>Finds the maximum and minimum pixel value
* in each band of an image.</td></tr>
* <tr><td>DocURL</td> <td>http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ExtremaDescriptor.html</td></tr>
* <tr><td>Version</td> <td>1.0</td></tr>
* <tr><td>arg0Desc</td> <td>The region of the image to scan.</td></tr>
* <tr><td>arg1Desc</td> <td>The horizontal sampling rate,
* may not be less than 1.</td></tr>
* <tr><td>arg2Desc</td> <td>The vertical sampling rate,
* may not be less than 1.</td></tr>
* <tr><td>arg3Desc</td> <td>Whether to store extrema locations.</td></tr>
* <tr><td>arg4Desc</td> <td>Maximum number of run length codes to store.</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>roi</td> <td>com.lightcrafts.mediax.jai.ROI</td>
* <td>null</td>
* <tr><td>xPeriod</td> <td>java.lang.Integer</td>
* <td>1</td>
* <tr><td>yPeriod</td> <td>java.lang.Integer</td>
* <td>1</td>
* <tr><td>saveLocations</td> <td>java.lang.Boolean</td>
* <td>Boolean.FALSE</td>
* <tr><td>maxRuns</td> <td>java.lang.Integer</td>
* <td>1</td>
* </table></p>
*
* @see com.lightcrafts.mediax.jai.OperationDescriptor
*/
public class ExtremaDescriptor extends OperationDescriptorImpl {
/**
* The resource strings that provide the general documentation
* and specify the parameter list for this operation.
*/
private static final String[][] resources = {
{"GlobalName", "Extrema"},
{"LocalName", "Extrema"},
{"Vendor", "com.lightcrafts.media.jai"},
{"Description", JaiI18N.getString("ExtremaDescriptor0")},
{"DocURL", "http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/ExtremaDescriptor.html"},
{"Version", JaiI18N.getString("DescriptorVersion")},
{"arg0Desc", JaiI18N.getString("ExtremaDescriptor1")},
{"arg1Desc", JaiI18N.getString("ExtremaDescriptor2")},
{"arg2Desc", JaiI18N.getString("ExtremaDescriptor3")},
{"arg3Desc", JaiI18N.getString("ExtremaDescriptor4")},
{"arg4Desc", JaiI18N.getString("ExtremaDescriptor5")}
};
/** The parameter name list for this operation. */
private static final String[] paramNames = {
"roi", "xPeriod", "yPeriod", "saveLocations", "maxRuns"
};
/** The parameter class list for this operation. */
private static final Class[] paramClasses = {
com.lightcrafts.mediax.jai.ROI.class,
java.lang.Integer.class,
java.lang.Integer.class,
java.lang.Boolean.class,
java.lang.Integer.class
};
/** The parameter default value list for this operation. */
private static final Object[] paramDefaults = {
null, new Integer(1), new Integer(1),
Boolean.FALSE, new Integer(1)
};
/** Constructor. */
public ExtremaDescriptor() {
super(resources, 1, paramClasses, paramNames, paramDefaults);
}
/**
* Returns the minimum legal value of a specified numeric parameter
* for this operation.
*/
public Number getParamMinValue(int index) {
if (index == 0 || index == 3) {
return null;
} else if (index == 1 || index == 2 || index == 4) {
return new Integer(1);
} else {
throw new ArrayIndexOutOfBoundsException();
}
}
/**
* Finds the maximum and minimum pixel value in each band of 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 roi The region of the image to scan.
* May be <code>null</code>.
* @param xPeriod The horizontal sampling rate, may not be less than 1.
* May be <code>null</code>.
* @param yPeriod The vertical sampling rate, may not be less than 1.
* May be <code>null</code>.
* @param saveLocations Whether to store extrema locations.
* May be <code>null</code>.
* @param maxRuns Maximum number of run length codes to store.
* May be <code>null</code>.
* @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>.
*/
public static RenderedOp create(RenderedImage source0,
ROI roi,
Integer xPeriod,
Integer yPeriod,
Boolean saveLocations,
Integer maxRuns,
RenderingHints hints) {
ParameterBlockJAI pb =
new ParameterBlockJAI("Extrema",
RenderedRegistryMode.MODE_NAME);
pb.setSource("source0", source0);
pb.setParameter("roi", roi);
pb.setParameter("xPeriod", xPeriod);
pb.setParameter("yPeriod", yPeriod);
pb.setParameter("saveLocations", saveLocations);
pb.setParameter("maxRuns", maxRuns);
return JAI.create("Extrema", pb, hints);
}
}