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

Wayan Saryada

Wayan Saryada

A programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, JPA, etc. If you need help on Java programming you can hire me on Fiverr.
Wayan Saryada

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