GhostImageFigure.java

/*******************************************************************************
 * Copyright (c) 2010, 2012 IBM Corporation, Gerhardt Informatics Kft. and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Gerhardt Informatics Kft. - GEFGWT port
 *******************************************************************************/
package org.eclipse.draw2d;

import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.RGB;

/**
 * A figure used to render a partly transparent copy of an original source
 * figure.
 * 
 * This class is pretty much based on a sample, posted within the GEF newsgroup
 * (http://dev.eclipse.org/newslists/news.eclipse.tools.gef/msg15158.html),
 * although we decided to not cache the ghost image itself (but only its image
 * data), so the figure does not have to be disposed (and may thus directly
 * extend {@link Figure} rather than {@link ImageFigure}).
 * 
 * @author Alexander Nyssen
 * @author Philip Ritzkopf
 * 
 * @since 3.6
 */
public class GhostImageFigure extends Figure {

	private int alpha = -1;
	private ImageData ghostImageData;

	/**
	 * The single constructor.
	 * 
	 * @param source
	 *            The original figure that will be used to render the ghost
	 *            image.
	 * @param alpha
	 *            The desired transparency value, to be forwarded to
	 *            {@link Graphics#setAlpha(int)}.
	 * @param transparency
	 *            The RBG value of the color that is to be regarded as
	 *            transparent. May be <code>null</code>.
	 */
	public GhostImageFigure(final IFigure source, int alpha, RGB transparency) {
		// this.alpha = alpha;
		//
		// Rectangle sourceFigureRelativePrecisionBounds = new
		// PrecisionRectangle(
		// source.getBounds().getCopy());
		//
		// Image offscreenImage = new Image(Display.getCurrent(),
		// sourceFigureRelativePrecisionBounds.width,
		// sourceFigureRelativePrecisionBounds.height);
		//
		// GC gc = new GC(offscreenImage);
		// SWTGraphics swtGraphics = new SWTGraphics(gc);
		// swtGraphics.translate(-sourceFigureRelativePrecisionBounds.x,
		// -sourceFigureRelativePrecisionBounds.y);
		// source.paint(swtGraphics);
		//
		// ghostImageData = offscreenImage.getImageData();
		// if (transparency != null) {
		// ghostImageData.transparentPixel = ghostImageData.palette
		// .getPixel(transparency);
		// }
		//
		// offscreenImage.dispose();
		// swtGraphics.dispose();
		// gc.dispose();
	}

	/**
	 * @see Figure#paintFigure(Graphics)
	 */
	protected void paintFigure(Graphics graphics) {
		// Image feedbackImage = new Image(Display.getCurrent(),
		// ghostImageData);
		// graphics.setAlpha(alpha);
		// graphics.setClip(getBounds().getCopy());
		// graphics.drawImage(feedbackImage, 0, 0, ghostImageData.width,
		// ghostImageData.height, getBounds().x, getBounds().y,
		// getBounds().width, getBounds().height);
		// feedbackImage.dispose();
	}
}