How do I draw a rectangle in Java 2D?

The code snippet below show you how to use the Graphics2D class the draw a rectangle. You can see the snippet in the paintComponent(Graphics g) method defined in the anonymous JPanel object.

To draw a rectangle we use the Rectangle2D.Double static-inner class. The constructor of this class accept the information about the rectangle x, y coordinates and its witdh and height.

package org.kodejava.example.awt.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Rectangle2D;

public class DrawRectangle {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("Draw Rectangle");
                frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
                frame.add(new JPanel() {
                    @Override
                    protected void paintComponent(Graphics g) {
                        //
                        // Draw a rectangle using Rectangle2D class
                        //
                        Graphics2D g2 = (Graphics2D) g;
                        g2.setColor(Color.RED);

                        double x = 100;
                        double y = 100;
                        double width = x + 200;
                        double height = y + 50;
                       
                        //
                        // Draw the red rectangle
                        //
                        g2.draw(new Rectangle2D.Double(x, y, width, height));

                        g2.setColor(Color.BLUE);
                        //
                        // Draw the blue rectangle
                        //
                        g2.draw(new Rectangle2D.Double(150, 50, 200, 250));
                    }
                }, BorderLayout.CENTER);

                frame.pack();
                frame.setSize(new Dimension(500, 400));
                frame.setVisible(true);
            }
        });
    }
}

Here is the result you’ll get when you run the snippet:

Draw Rectangle Demo

Wayan Saryada

I am a programmer, a runner, an open water diver and currently living in the island of Bali, Indonesia. If you need help on Java programming you can hire me on Fiverr.

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