HourGlass.java

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Area;
import java.awt.geom.GeneralPath;
import java.awt.geom.Rectangle2D;
import java.util.concurrent.TimeUnit;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

public class HourGlass extends JFrame {

	public static void main(String[] args) {
		new HourGlass();
	}

	public HourGlass() {
		EventQueue.invokeLater(new Runnable() {
			@Override
			public void run() {
				setBackground(new Color(0, 0, 0, 0));
				Canvas c = new Canvas(0,1);
				setContentPane(c);
				pack();
				 setSize(120, 300);
				setLocationRelativeTo(null);
				setVisible(true);
			}
		});
	}

}

class Canvas extends JPanel implements ActionListener{

	private int off;
	private int hh,mm,elapsed;
	private int h = 100;
	private int tick;
	Timer t;
	public Canvas(int hh, int mm) {
		super();
		this.hh = hh;
		this.mm = mm;
		tick = ((hh * 3600 + mm * 60) * 1000) / h;
		t = new Timer(tick, this);
		t.start();
	}
	

	@Override
	public void paintComponent(Graphics g) {
		int x = 0, y = 0, w = 100;
		Graphics2D g2 = (Graphics2D) g;
		g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
				RenderingHints.VALUE_ANTIALIAS_ON);

		g2.clearRect(x, y, w, h * 2+20);
		g2.setColor(Color.orange);
		
		GeneralPath polygon = new GeneralPath(GeneralPath.WIND_NON_ZERO, 4);
		
		polygon.moveTo(x, y);
		polygon.quadTo(x, h, w / 2, h);
		polygon.quadTo(x, h, x, h * 2);
		polygon.lineTo(w, h * 2);
		polygon.quadTo(w, h, w / 2, h);
		polygon.quadTo(w, h, w, y);
		polygon.closePath();
		
		Rectangle2D mask = new Rectangle2D.Double(x, y + off, w, h - off);
		Rectangle2D mask2 = new Rectangle2D.Double(x, y + 2 * h - off, w, off);
		Area a1 = new Area(mask);
		
		Area a2 = new Area(polygon);
		a2.intersect(a1);
		g2.fill(a2);
		
		a1 = new Area(mask2);
		a2 = new Area(polygon);
		a2.intersect(a1);
		g2.fill(a2);
		g2.setStroke(new BasicStroke(1));
		g2.setColor(new Color(0xCCCCCC));
		g2.draw(polygon);

		int millis = ((hh * 3600 + mm * 60) * 1000) - elapsed;
		String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(millis),
	            TimeUnit.MILLISECONDS.toMinutes(millis) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(millis)),
	            TimeUnit.MILLISECONDS.toSeconds(millis) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(millis)));
		g2.drawString(hms, 10, 210);
	}

	@Override
	public void actionPerformed(ActionEvent arg0) {
		off = off + 1;
		elapsed = elapsed + tick;
		repaint();
		
		if(off == h){
			t.stop();
		}
	}
}