RingShell.java Source code

Introduction

Here is the source code for RingShell.java

Source

/******************************************************************************
 * Copyright (c) 1998, 2004 Jackwind Li Guojie
 * All right reserved. 
 * 
 * Created on Jan 25, 2004 7:58:06 PM by JACK
 * $Id$
 * 
 * visit: http://www.asprise.com/swt
 *****************************************************************************/

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseListener;
import org.eclipse.swt.events.MouseMoveListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class RingShell {
    static int[] createCircle(int radius, int centerX, int centerY) {
        int[] points = new int[360 * 2];
        for (int i = 0; i < 360; i++) {
            points[i * 2] = centerX + (int) (radius * Math.cos(Math.toRadians(i)));
            points[i * 2 + 1] = centerY + (int) (radius * Math.sin(Math.toRadians(i)));
        }
        return points;
    }

    static Point originalPosition = null;

    public static void main(String[] args) {
        final Display display = new Display();
        final Shell shell = new Shell(display, SWT.NO_TRIM | SWT.ON_TOP);
        shell.setBackground(display.getSystemColor(SWT.COLOR_DARK_MAGENTA));

        Region region = new Region();
        region.add(createCircle(100, 100, 100));
        region.subtract(createCircle(50, 100, 100));
        shell.setRegion(region);

        // Make the shell movable by using the mouse pointer. 
        shell.addMouseListener(new MouseListener() {
            public void mouseDoubleClick(MouseEvent e) {
                shell.dispose(); // Double click to dispose the shell.
            }

            public void mouseDown(MouseEvent e) {
                originalPosition = new Point(e.x, e.y);
            }

            public void mouseUp(MouseEvent e) {
                originalPosition = null;
            }
        });

        shell.addMouseMoveListener(new MouseMoveListener() {
            public void mouseMove(MouseEvent e) {
                if (originalPosition == null)
                    return;
                Point point = display.map(shell, null, e.x, e.y);
                shell.setLocation(point.x - originalPosition.x, point.y - originalPosition.y);
                System.out.println("Moved from: " + originalPosition + " to " + point);
            }
        });

        Rectangle regionBounds = region.getBounds();
        shell.setSize(regionBounds.width, regionBounds.height);
        shell.open();

        // Set up the event loop.
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                // If no more entries in event queue
                display.sleep();
            }
        }
        display.dispose();
        region.dispose();

    }

}