How do I draw a line in Java 2D?

The following code snippet show you how to draw a simple line using Graphics2D.draw() method. This method take a parameter that implements the java.awt.Shape interface.

To draw a line we can use the Line2D.Double static-inner class. This class constructor takes four integers values that represent the start (x1, y1) and end (x2, y2) coordinate of the line.

package org.kodejava.awt.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Line2D;

public class DrawLine extends JComponent {
    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw Line");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawLine());
        frame.pack();
        frame.setSize(new Dimension(420, 440));
        frame.setVisible(true);
    }

    @Override
    public void paint(Graphics g) {
        // Draw a simple line using the Graphics2D draw() method.
        Graphics2D g2 = (Graphics2D) g;
        g2.setStroke(new BasicStroke(2f));
        g2.setColor(Color.RED);
        g2.draw(new Line2D.Double(50, 150, 250, 350));
        g2.setColor(Color.GREEN);
        g2.draw(new Line2D.Double(250, 350, 350, 250));
        g2.setColor(Color.BLUE);
        g2.draw(new Line2D.Double(350, 250, 150, 50));
        g2.setColor(Color.YELLOW);
        g2.draw(new Line2D.Double(150, 50, 50, 150));
        g2.setColor(Color.BLACK);
        g2.draw(new Line2D.Double(0, 0, 400, 400));
    }
}

When you run the snippet it will show you something like:

Draw 2D Line

Draw 2D Line

Wayan

2 Comments

    • Hi,

      If you want to change the thickness of the line you can change the value of the stroke size that is used to draw the line. See the g2.setStroke() line in the code snippet above.

      Reply

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.