How do I draw a string in Java 2D?

The code snippet below show you how to draw a string using Graphics2D. The drawString() method accept the string to be drawn and their x and y coordinate. Here you can also see how to set the antialiasing mode using the setRenderingHint() method.

package org.kodejava.example.awt.geom;

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

public class DrawString extends JPanel {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
       
        //
        // Define rendering hint, font name, font style and font size
        //
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setFont(new Font(Font.SERIF, Font.ITALIC, 40));
        g2.setPaint(Color.BLUE);
       
        //
        // Draw Hello World String
        //
        g2.drawString("Hello World!", 100, 100);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setTitle("Draw String Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(new DrawString());
        frame.pack();
        frame.setSize(400, 300);
        frame.setVisible(true);
    }
}

Run the snippet and you’ll see the following screen:

Draw String Demo

How do I draw a vertical text in Java 2D?

To draw a text / string vertically we need to do a transform on the Graphics2D object. First, create an instance of AffineTransform and set the rotation using the setToRotation() method. And then pass this transform object into g2.setTransform() method.

package org.kodejava.example.awt.geom;

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

public class DrawVerticalText extends JPanel {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        //
        // Define rendering hint, font name, font style and font size
        //
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setFont(new Font(Font.SERIF, Font.BOLD, 20));

        //
        // Rotate 90 degree to make a vertical text
        //
        AffineTransform at = new AffineTransform();
        at.setToRotation(Math.toRadians(90), 10, 10);
        g2.setTransform(at);
        g2.drawString("This is a vertical text", 10, 10);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setTitle("Draw Vertical Text Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(new DrawVerticalText());
        frame.pack();
        frame.setSize(200, 300);
        frame.setVisible(true);
    }
}

Run the snippet and you’ll see the following screen:

Draw Vertical Text Demo

How do I create a gradient paint in Java 2D?

To change the color of a graphics shape we can use the setPaint() method. For a simple coloring we can pass the color object into this method, such as Color.RED or Color.GREE.

If you want to paint with a gradient paint you can use the GradientPaint class. This class provides a way to fill a shape with a linear color gradient pattern. To create a gradient color pattern you can pass the following parameter to the object constructor.

  • x1: x coordinate of the first specified point in user space
  • y1: y coordinate of the first specified point in user space
  • color1: color at the first specified point
  • x2: x coordinate of the second specified point in user space
  • y2: y coordinate of the second specified point in user space
  • color2: color at the second specified point

package org.kodejava.example.awt.geom;

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

public class GradientPaintDemo extends JApplet {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        GradientPaint blackToGray = new GradientPaint(50, 50, Color.BLACK,
                300, 100, Color.LIGHT_GRAY);
        g2.setPaint(blackToGray);
        g2.fill(new Rectangle2D.Double(50, 50, 300, 100));

        GradientPaint blueToBlack = new GradientPaint(0, 0, Color.BLUE,
                400, 400, Color.BLACK);
        g2.setPaint(blueToBlack);
        g2.fill(new Rectangle2D.Double(50, 160, 300, 100));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Gradient Paint Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        JApplet applet = new GradientPaintDemo();
        frame.getContentPane().add(applet);
        frame.pack();
        frame.setSize(new Dimension(400, 350));
        frame.setVisible(true);
    }
}

This code snippet produce the following output:

Gradient Paint Demo