public static void main(String[] args) {
    final Display display = new Display();
    final Image image = display.getSystemImage(SWT.ICON_INFORMATION);
    final Shell shell = new Shell(display, SWT.NO_TRIM);
    Region region = new Region();
    final ImageData imageData = image.getImageData();
    if (imageData.alphaData != null) {
      Rectangle pixel = new Rectangle(0, 0, 1, 1);
      for (int y = 0; y < imageData.height; y++) {
        for (int x = 0; x < imageData.width; x++) {
          if (imageData.getAlpha(x, y) == 255) {
            pixel.x = imageData.x + x;
            pixel.y = imageData.y + y;
            region.add(pixel);
          }
        }
      }
    } else {
      ImageData mask = imageData.getTransparencyMask();
      Rectangle pixel = new Rectangle(0, 0, 1, 1);
      for (int y = 0; y < mask.height; y++) {
        for (int x = 0; x < mask.width; x++) {
          if (mask.getPixel(x, y) != 0) {
            pixel.x = imageData.x + x;
            pixel.y = imageData.y + y;
            region.add(pixel);
          }
        }
      }
    }
    shell.setRegion(region);

    Listener l =
        new Listener() {
          /** The x/y of the MouseDown, relative to top-left of the shell. */
          int startX, startY;

          @Override
          public void handleEvent(Event e) {
            if (e.type == SWT.KeyDown && e.character == SWT.ESC) {
              shell.dispose();
            }
            if (e.type == SWT.MouseDown && e.button == 1) {
              Point p = shell.toDisplay(e.x, e.y);
              Point loc = shell.getLocation();
              startX = p.x - loc.x;
              startY = p.y - loc.y;
            }
            if (e.type == SWT.MouseMove && (e.stateMask & SWT.BUTTON1) != 0) {
              Point p = shell.toDisplay(e.x, e.y);
              p.x -= startX;
              p.y -= startY;
              shell.setLocation(p);
            }
            if (e.type == SWT.Paint) {
              e.gc.drawImage(image, imageData.x, imageData.y);
            }
          }
        };
    shell.addListener(SWT.KeyDown, l);
    shell.addListener(SWT.MouseDown, l);
    shell.addListener(SWT.MouseMove, l);
    shell.addListener(SWT.Paint, l);

    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) display.sleep();
    }
    region.dispose();
    image.dispose();
    display.dispose();
  }
  public static void main(String[] args) {
    final Display display = new Display();
    // 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 that looks like a key hole
    Region region = new Region();
    region.add(circle(67, 67, 67));
    region.subtract(circle(20, 67, 50));
    region.subtract(new int[] {67, 50, 55, 105, 79, 105});
    // define the shape of the shell using setRegion
    shell.setRegion(region);
    Rectangle size = region.getBounds();
    shell.setSize(size.width, size.height);
    // add ability to move shell around
    Listener l =
        new Listener() {
          /** The x/y of the MouseDown, relative to top-left of the shell. */
          Point origin;

          @Override
          public void handleEvent(Event e) {
            switch (e.type) {
              case SWT.MouseDown:
                Point point = shell.toDisplay(e.x, e.y);
                Point loc = shell.getLocation();
                origin = new Point(point.x - loc.x, point.y - loc.y);
                break;
              case SWT.MouseUp:
                origin = null;
                break;
              case SWT.MouseMove:
                if (origin != null) {
                  Point p = display.map(shell, null, e.x, e.y);
                  shell.setLocation(p.x - origin.x, p.y - origin.y);
                }
                break;
            }
          }
        };
    shell.addListener(SWT.MouseDown, l);
    shell.addListener(SWT.MouseUp, l);
    shell.addListener(SWT.MouseMove, l);
    // add ability to close shell
    Button b = new Button(shell, SWT.PUSH);
    b.setBackground(shell.getBackground());
    b.setText("close");
    b.pack();
    b.setLocation(10, 68);
    b.addListener(
        SWT.Selection,
        new Listener() {
          @Override
          public void handleEvent(Event e) {
            shell.close();
          }
        });
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) display.sleep();
    }
    region.dispose();
    display.dispose();
  }