JButton with non-rectangular shape

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;

public class TriangleButton extends JButton {
public TriangleButton(String label) {
super(label);

// These statements enlarge the button so that it
// becomes a circle rather than an oval.
Dimension size = getPreferredSize();
size.width = size.height = Math.max(size.width,
size.height);
setPreferredSize(size);

// This call causes the JButton not to paint
// the background.
// This allows us to paint a round background.
setContentAreaFilled(false);
}

// Paint the round background and label.
protected void paintComponent(Graphics g) {
if (getModel().isArmed()) {
// You might want to make the highlight color
// a property of the RoundButton class.
g.setColor(Color.lightGray);
} else {
g.setColor(getBackground());
}

int x3Points[] = {getSize().width/2, 0, getSize().width};
int y3Points[] = {0, getSize().height, getSize().height};
g.fillPolygon(x3Points, y3Points, x3Points.length);

// This call will paint the label and the
// focus rectangle.
super.paintComponent(g);
}

// Paint the border of the button using a simple stroke.
protected void paintBorder(Graphics g) {
g.setColor(getForeground());
int x3Points[] = {getSize().width/2, 0, getSize().width};
int y3Points[] = {0, getSize().height, getSize().height};
g.drawPolygon(x3Points, y3Points, x3Points.length);
}

// Hit detection.
Polygon polygon;
public boolean contains(int x, int y) {
// If the button has changed size,
// make a new shape object.
if (polygon == null ||
!polygon.getBounds().equals(getBounds())) {
int x3Points[] = {getSize().width/2, 0, getSize().width};
int y3Points[] = {0, getSize().height, getSize().height};
polygon = new Polygon(x3Points,y3Points,3);
}
return polygon.contains(x, y);
}

// Test routine.
public static void main(String[] args) {
// Create a button with the label "Jackpot".
JButton button = new TriangleButton("Jackpot");
button.setBackground(Color.green);

// Create a frame in which to show the button.
JFrame frame = new JFrame();
frame.getContentPane().setBackground(Color.yellow);
frame.getContentPane().add(button);
frame.getContentPane().setLayout(new FlowLayout());
frame.setSize(150, 150);
frame.setVisible(true);
}
}