/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2006-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.coverage.processing.operation;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.RenderedImage;
import javax.media.jai.ImageLayout;
import javax.media.jai.NullOpImage;
import javax.media.jai.OpImage;
import org.opengis.coverage.Coverage;
import org.opengis.coverage.SampleDimension;
import org.opengis.coverage.grid.GridCoverage;
import org.opengis.parameter.ParameterValueGroup;
import org.geotools.factory.Hints;
import org.geotools.coverage.CoverageFactoryFinder;
import org.geotools.coverage.GridSampleDimension;
import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.coverage.grid.ViewType;
import org.geotools.coverage.processing.Operation2D;
import org.geotools.parameter.DefaultParameterDescriptorGroup;
import org.geotools.resources.coverage.CoverageUtilities;
import org.geotools.resources.image.ColorUtilities;
import org.geotools.resources.Classes;
import org.geotools.resources.i18n.ErrorKeys;
import org.geotools.resources.i18n.Errors;
/**
* Operation applied only on image's colors. This operation work only for source
* image using an {@link IndexColorModel}.
*
* @source $URL$
* @version $Id$
* @author Martin Desruisseaux
*
* @todo Consider moving this class to the {@link org.geotools.coverage.processing} package.
*/
abstract class IndexColorOperation extends Operation2D {
/**
* Constructs an operation.
*/
public IndexColorOperation(final DefaultParameterDescriptorGroup descriptor) {
super(descriptor);
}
/**
* Performs the color transformation. This method invokes the
* {@link #transformColormap transformColormap(...)} method with current RGB
* colormap, the source {@link SampleDimension} and the supplied parameters.
*
* @param parameters The parameters.
* @param hints Rendering hints (ignored in this implementation).
*
* @throws IllegalArgumentException if the candidate image do not use an
* {@link IndexColorModel}.
*/
public Coverage doOperation(final ParameterValueGroup parameters, final Hints hints) {
final GridCoverage2D source = (GridCoverage2D) parameters.parameter("Source").getValue();
final GridCoverage2D visual = source.view(ViewType.RENDERED);
final RenderedImage image = visual.getRenderedImage();
final GridSampleDimension[] bands = visual.getSampleDimensions();
final int visibleBand = CoverageUtilities.getVisibleBand(image);
ColorModel model = image.getColorModel();
boolean colorChanged = false;
for (int i=0; i<bands.length; i++) {
/*
* Extracts the ARGB codes from the IndexColorModel and invokes the
* transformColormap(...) method, which needs to be defined by subclasses.
*/
GridSampleDimension band = bands[i];
final ColorModel candidate = (i == visibleBand) ? image.getColorModel() : band.getColorModel();
if (!(candidate instanceof IndexColorModel)) {
// Current implementation supports only sources that use an index color model.
throw new IllegalArgumentException(Errors.format(ErrorKeys.ILLEGAL_CLASS_$2,
Classes.getClass(candidate), IndexColorModel.class));
}
final IndexColorModel colors = (IndexColorModel) candidate;
final int mapSize = colors.getMapSize();
final int[] ARGB = new int[mapSize];
colors.getRGBs(ARGB);
band = transformColormap(ARGB, i, band, parameters);
/*
* Checks if there is any change, either as a new GridSampleDimension instance or in
* the ARGB array. Note that if the new GridSampleDimension is equals to the old one,
* then the new one will be discarted since the old one is more likely to be a shared
* instance.
*/
if (!bands[i].equals(band)) {
bands[i] = band;
colorChanged = true;
} else if (!colorChanged) {
for (int j=0; j<mapSize; j++) {
if (ARGB[j] != colors.getRGB(j)) {
colorChanged = true;
break;
}
}
}
/*
* If we changed the color of the visible band, then create immediately a new
* color model for this band. The new color model will be given later to the
* image operator.
*/
if (colorChanged && (i == visibleBand)) {
model = ColorUtilities.getIndexColorModel(ARGB, bands.length, visibleBand);
}
}
if (!colorChanged) {
return source;
}
/*
* Gives the color model to the image layout and creates a new image using the Null
* operation, which merely propagates its first source along the operation chain
* unmodified (except for the ColorModel given in the layout in this case).
*/
final ImageLayout layout = new ImageLayout().setColorModel(model);
final RenderedImage newImage = new NullOpImage(image, layout, null, OpImage.OP_COMPUTE_BOUND);
final GridCoverage2D target = CoverageFactoryFinder.getGridCoverageFactory(null).create(
visual.getName(), newImage,
visual.getCoordinateReferenceSystem2D(),
visual.getGridGeometry().getGridToCRS(),
bands, new GridCoverage[] { visual }, null);
if (source != visual) {
// TODO: needs to select the right type.
return target.geophysics(true);
}
return target;
}
/**
* Transforms the supplied RGB colors. This method is automatically invoked
* by {@link #doOperation(ParameterList)} for each band in the source
* {@link GridCoverage2D}. The {@code ARGB} array contains the ARGB values
* from the current source and should be overridden with new ARGB values
* for the destination image.
*
* @param ARGB
* Alpha, Red, Green and Blue components to transform.
* @param band
* The band number, from 0 to the number of bands in the image -1.
* @param sampleDimension
* The sample dimension of band {@code band}.
* @param parameters
* The user-supplied parameters.
* @return A sample dimension identical to {@code sampleDimension} except for the
* colors. Subclasses may conservatively returns {@code sampleDimension}.
*/
protected abstract GridSampleDimension transformColormap(final int[] ARGB, final int band,
final GridSampleDimension sampleDimension, final ParameterValueGroup parameters);
}