/*
* $RCSfile: RescaleDescriptor.java,v $
*
* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
*
* Use is subject to license terms.
*
* $Revision: 1.1 $
* $Date: 2005/02/11 04:57:43 $
* $State: Exp $
*/
package com.lightcrafts.mediax.jai.operator;
import java.awt.RenderingHints;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.ParameterBlock;
import java.awt.image.renderable.RenderableImage;
import com.lightcrafts.mediax.jai.JAI;
import com.lightcrafts.mediax.jai.OperationDescriptorImpl;
import com.lightcrafts.mediax.jai.ParameterBlockJAI;
import com.lightcrafts.mediax.jai.RenderableOp;
import com.lightcrafts.mediax.jai.RenderedOp;
import com.lightcrafts.mediax.jai.registry.RenderableRegistryMode;
import com.lightcrafts.mediax.jai.registry.RenderedRegistryMode;
/**
* An <code>OperationDescriptor</code> describing the "Rescale" operation.
*
* <p> The "Rescale" operation takes a rendered or renderable source
* image and maps the pixel values of an image from one range to
* another range by multiplying each pixel value by one of a set of
* constants and then adding another constant to the result of the
* multiplication. If the number of constants supplied is less than
* the number of bands of the destination, then the constant from
* entry 0 is applied to all the bands. Otherwise, a constant from a
* different entry is applied to each band. There must be at least one
* entry in each of the contants and offsets arrays.
*
* <p> The destination pixel values are defined by the pseudocode:
* <pre>
* constant = (constants.length < dstNumBands) ?
* constants[0] : constants[b];
* offset = (offsets.length < dstNumBands) ?
* offsets[0] : offsets[b];
*
* dst[x][y][b] = src[x][y][b]*constant + offset;
* </pre>
*
* <p> The pixel arithmetic is performed using the data type of the
* destination image. By default, the destination will have the same
* data type as the source image unless an <code>ImageLayout</code>
* containing a <code>SampleModel</code> with a different data type
* is supplied as a rendering hint.
*
* <p><table border=1>
* <caption>Resource List</caption>
* <tr><th>Name</th> <th>Value</th></tr>
* <tr><td>GlobalName</td> <td>Rescale</td></tr>
* <tr><td>LocalName</td> <td>Rescale</td></tr>
* <tr><td>Vendor</td> <td>com.lightcrafts.media.jai</td></tr>
* <tr><td>Description</td> <td>Maps the pixels values of an image from
* one range to another range.</td></tr>
* <tr><td>DocURL</td> <td>http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/RescaleDescriptor.html</td></tr>
* <tr><td>Version</td> <td>1.0</td></tr>
* <tr><td>arg0Desc</td> <td>The per-band constants to multiply by.</td></tr>
* <tr><td>arg1Desc</td> <td>The per-band offsets to be added.</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>constants</td> <td>double[]</td>
* <td>{1.0}</td>
* <tr><td>offsets</td> <td>double[]</td>
* <td>{0.0}</td>
* </table></p>
*
* @see com.lightcrafts.mediax.jai.OperationDescriptor
*/
public class RescaleDescriptor extends OperationDescriptorImpl {
/**
* The resource strings that provide the general documentation
* and specify the parameter list for this operation.
*/
private static final String[][] resources = {
{"GlobalName", "Rescale"},
{"LocalName", "Rescale"},
{"Vendor", "com.lightcrafts.media.jai"},
{"Description", JaiI18N.getString("RescaleDescriptor0")},
{"DocURL", "http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/RescaleDescriptor.html"},
{"Version", JaiI18N.getString("DescriptorVersion")},
{"arg0Desc", JaiI18N.getString("RescaleDescriptor1")},
{"arg1Desc", JaiI18N.getString("RescaleDescriptor2")}
};
/** The parameter class list for this operation. */
private static final Class[] paramClasses = {
double[].class, double[].class
};
/** The parameter name list for this operation. */
private static final String[] paramNames = {
"constants", "offsets"
};
/** The parameter default value list for this operation. */
private static final Object[] paramDefaults = {
new double[] {1.0}, new double[] {0.0}
};
/** Constructor. */
public RescaleDescriptor() {
super(resources, 1, paramClasses, paramNames, paramDefaults);
}
/** Returns <code>true</code> since renderable operation is supported. */
public boolean isRenderableSupported() {
return true;
}
/**
* Validates the input parameters.
*
* <p> In addition to the standard checks performed by the
* superclass method, this method checks that the length of the
* "constants" and "offsets" arrays are each at least 1.
*/
protected boolean validateParameters(ParameterBlock args,
StringBuffer msg) {
if (!super.validateParameters(args, msg)) {
return false;
}
int constantsLength = ((double[])args.getObjectParameter(0)).length;
int offsetsLength = ((double[])args.getObjectParameter(1)).length;
if (constantsLength < 1) {
msg.append(getName() + " " +
JaiI18N.getString("RescaleDescriptor3"));
return false;
}
if (offsetsLength < 1) {
msg.append(getName() + ": " +
JaiI18N.getString("RescaleDescriptor4"));
return false;
}
return true;
}
/**
* Maps the pixels values of an image from one range to another range.
*
* <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 constants The per-band constants to multiply by.
* May be <code>null</code>.
* @param offsets The per-band offsets to be added.
* 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,
double[] constants,
double[] offsets,
RenderingHints hints) {
ParameterBlockJAI pb =
new ParameterBlockJAI("Rescale",
RenderedRegistryMode.MODE_NAME);
pb.setSource("source0", source0);
pb.setParameter("constants", constants);
pb.setParameter("offsets", offsets);
return JAI.create("Rescale", pb, hints);
}
/**
* Maps the pixels values of an image from one range to another range.
*
* <p>Creates a <code>ParameterBlockJAI</code> from all
* supplied arguments except <code>hints</code> and invokes
* {@link JAI#createRenderable(String,ParameterBlock,RenderingHints)}.
*
* @see JAI
* @see ParameterBlockJAI
* @see RenderableOp
*
* @param source0 <code>RenderableImage</code> source 0.
* @param constants The per-band constants to multiply by.
* May be <code>null</code>.
* @param offsets The per-band offsets to be added.
* May be <code>null</code>.
* @param hints The <code>RenderingHints</code> to use.
* May be <code>null</code>.
* @return The <code>RenderableOp</code> destination.
* @throws IllegalArgumentException if <code>source0</code> is <code>null</code>.
*/
public static RenderableOp createRenderable(RenderableImage source0,
double[] constants,
double[] offsets,
RenderingHints hints) {
ParameterBlockJAI pb =
new ParameterBlockJAI("Rescale",
RenderableRegistryMode.MODE_NAME);
pb.setSource("source0", source0);
pb.setParameter("constants", constants);
pb.setParameter("offsets", offsets);
return JAI.createRenderable("Rescale", pb, hints);
}
}