/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org. All rights reserved.
* This code is licensed under the GPL 2.0 license, availible at the root
* application directory.
*/
package org.vfny.geoserver.wms.responses.legend.gif;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.IOException;
import java.io.OutputStream;
import org.geoserver.platform.ServiceException;
import org.geotools.image.ImageWorker;
import org.vfny.geoserver.wms.responses.DefaultRasterLegendProducer;
import org.vfny.geoserver.wms.responses.ImageUtils;
/**
* Producer of legend graphics in image/gif format.
*
* @author Gabriel Roldan, Axios Engineering
* @version $Id: GifLegendGraphicProducer.java 9027 2008-05-28 07:18:12Z jdeolive $
*/
public class GifLegendGraphicProducer extends DefaultRasterLegendProducer {
/** DOCUMENT ME! */
static final String MIME_TYPE = "image/gif";
/**
* Creates a new producer of legends in gif format.
*/
public GifLegendGraphicProducer() {
super();
}
/**
* Encodes on the fly the image generated on {@linkPlain
* DefaultRasterLegendProducer#produceLegendGraphic(GetLegendGraphicRequest)}
* to <code>out</code> in "image/gif" format.
*
* @see org.vfny.geoserver.wms.responses.GetLegendGraphicProducer#writeTo(java.io.OutputStream)
*/
public void writeTo(OutputStream out) throws IOException, ServiceException {
//GR: shall we add a palette parameter to GetLegendGraphic too?
final BufferedImage legendGraphic = getLegendGraphic();
RenderedImage forcedIndexed8Bitmask = ImageUtils.forceIndexed8Bitmask(legendGraphic, null);
ImageWorker imageWorker = new ImageWorker(forcedIndexed8Bitmask);
imageWorker.writeGIF(out, "LZW", 0.75f);
}
/**
* Returns the "image/gif" mime type since that is the only output format
* this producer specializes on.
*
* @return <code>"image/gif"</code>
*
* @throws IllegalStateException if <code>super.getLegendGraphic() ==
* null</code>, to respect the workflow.
*
* @see org.vfny.geoserver.wms.responses.GetLegendGraphicProducer#getContentType()
*/
public String getContentType() throws IllegalStateException {
if (super.getLegendGraphic() == null) {
throw new IllegalStateException("the image was not still produced");
}
return MIME_TYPE;
}
}