examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet180.java

/*******************************************************************************
 * Copyright (c) 2000, 2014 IBM Corporation 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
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Create a non-rectangular shell to simulate transparency
 * (ESC to close shell)
 * 
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.0
 */
import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet180 {

public static void main(String[] args) {
	Display display = new Display();
	final Image image = display.getSystemImage(SWT.ICON_WARNING);
	//Shell must be created with style SWT.NO_TRIM
	final Shell shell = new Shell(display, SWT.NO_TRIM | SWT.ON_TOP);
	shell.setBackground(display.getSystemColor(SWT.COLOR_RED));
	//define a region 
	Region region = new Region();
	Rectangle pixel = new Rectangle(0, 0, 1, 1);
	for (int y = 0; y < 200; y+=2) {
			for (int x = 0; x < 200; x+=2) {
				pixel.x = x;
				pixel.y = y;
				region.add(pixel);
			}
		}
	//define the shape of the shell using setRegion
	shell.setRegion(region);
	shell.addPaintListener(new PaintListener() {
		@Override
		public void paintControl(PaintEvent e) {
			Rectangle bounds = image.getBounds();
			Point size = shell.getSize();
			e.gc.drawImage(image, 0, 0, bounds.width, bounds.height, 10, 10, size.x-20, size.y-20);
		}
	});
	shell.addListener(SWT.KeyDown, new Listener() {
		@Override
		public void handleEvent(Event e)  {
			if (e.character == SWT.ESC) {
				shell.dispose();
			}
		}
	});
	shell.open();
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch())
			display.sleep();
	}
	region.dispose();
	display.dispose();
}
}