/*
 * Copyright (c) 2000, 2002 IBM Corp.  All rights reserved.
 * This file is made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 */

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tracker;

public class Snippet0031 {

public static void main (String [] args) {
	final Display display = new Display ();
	final Shell shell = new Shell (display);
	final int jitter = 8;
	shell.setSize (200, 200);
	shell.open ();
	final Point [] point = new Point [1];
	shell.addListener (SWT.MouseDown, new Listener () {
		public void handleEvent (Event e) {
			point [0] = new Point (e.x, e.y);
		}
	});
	shell.addListener (SWT.MouseMove, new Listener () {
		public void handleEvent (Event e) {
			if (point [0] == null) return;
			if (Math.abs (point [0].x - e.x) < jitter && Math.abs (point [0].x - e.x) < jitter) {
				return;
			}
			GC gc = new GC (shell);
			gc.setBackground (gc.getForeground ());
			gc.fillRectangle (point [0].x, point [0].y, 2, 2);
			gc.dispose ();
			Tracker tracker = new Tracker (display, 0);
			Rectangle rect = shell.getClientArea ();
			Point pt = shell.toDisplay (new Point (rect.x, rect.y));
			rect.x = pt.x - (point [0].x - e.x);
			rect.y = pt.y - (point [0].y - e.y);
			tracker.setRectangles (new Rectangle [] {rect});
			tracker.open ();
			point [0] = null;
		}
	});
	shell.addListener (SWT.MouseUp, new Listener () {
		public void handleEvent (Event e) {
			point [0] = null;
		}
	});
	while (!shell.isDisposed()) {
		if (!display.readAndDispatch ()) display.sleep ();
	}
	display.dispose ();
}
}