import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class Rose {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		final Display display = new Display();
		final Shell shell = new Shell(display);

		shell.addPaintListener(new PaintListener() {
			public void paintControl(PaintEvent e) {
				final Rectangle rectangle = shell.getClientArea();
				final GC gc = e.gc;
				gc.setForeground(new Color(display, 255, 0, 0));
				final double radius = rectangle.width / 2 - 5;
				final int n = 1000;
				int lastx = 0, lasty = 0;
				for (int i = 0; i < n; ++i) {
					final double theta = 2 * Math.PI * i / n;
					final double r = Math.cos(3 * theta) * radius;
					final int x = (int) (rectangle.width / 2 + r
							* Math.cos(theta));
					final int y = (int) (rectangle.height / 2 + r
							* Math.sin(theta));

					if (i > 0) {
						gc.drawLine(lastx, lasty, x, y);
					}
					lastx = x;
					lasty = y;
				}
			}
		});

		shell.setText("Draw in a shell");
		shell.setSize(700 + 4 + 4, 700 + 34);
		shell.open();

		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
	}
}