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About Ilias Tsagklis

Ilias Tsagklis
Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.

Brightening or Darkening an RGB Buffered Image

In this tutorial we are going to see all that is necessary in order to brighten or darken an RGB Buffered Image from a source. This is one of the most basic image processing techniques that you will use when developing applications that involve images.

Basically, to brighten or darken a buffered image one should take the following steps:

  • Load an image from a URL using Toolkit.getDefaultToolkit().getImage method
  • Use an ImageObserver to monitor the loading of the image. When the image is fully load the user will be notified
  • Create a buffed image from the source image with a format more close to the custom display environment using GraphicsEnvironmentGraphicsDevice and GraphicsConfiguration to perform several image configurations
  • Draw the image into the buffered image
  • Use RescaleOp to set up the darkening or the brightening factor
  • And simply paint the buffered image in a new Frame
as you can see in the code snippet that follows:
package com.javacodegeeks.snippets.desktop;

import java.awt.Component;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.image.RescaleOp;

public class BufferedImageSaturation {

    static BufferedImage image;
    static boolean imageLoaded = false;

    public static void main(String[] args) {

  // The ImageObserver implementation to observe loading of the image

  ImageObserver myImageObserver = new ImageObserver() {

    public boolean imageUpdate(Image image, int flags, int x, int y, int width, int height) {

if ((flags & ALLBITS) != 0) {

  imageLoaded = true;

  System.out.println("Image loading finished!");

  return false;


return true;



  // The image URL - change to where your image file is located!

  String imageURL = "image.png";


   * This call returns immediately and pixels are loaded in the background

   * We use an ImageObserver to be notified when the loading of the image

   * is complete


  Image sourceImage = Toolkit.getDefaultToolkit().getImage(imageURL);


  // We wait until the image is fully loaded

  while (!imageLoaded) {

try {


} catch (InterruptedException e) {



  // Create a buffered image from the source image with a format that's compatible with the screen

  GraphicsEnvironment graphicsEnvironment = GraphicsEnvironment.getLocalGraphicsEnvironment();

  GraphicsDevice graphicsDevice = graphicsEnvironment.getDefaultScreenDevice();

  GraphicsConfiguration graphicsConfiguration = graphicsDevice.getDefaultConfiguration();

  // If the source image has no alpha info use Transparency.OPAQUE instead

  image = graphicsConfiguration.createCompatibleImage(sourceImage.getWidth(null), sourceImage.getHeight(null), Transparency.BITMASK);

  // Copy image to buffered image

  Graphics graphics = image.createGraphics();

  // Paint the image onto the buffered image

  graphics.drawImage(sourceImage, 0, 0, null);


  // Brighten the image by 20%

  float scaleFactor = 1.2f;

  RescaleOp op = new RescaleOp(scaleFactor, 0, null);

  image = op.filter(image, null);

  // Darken the image by 5%

  scaleFactor = 0.5f;

  op = new RescaleOp(scaleFactor, 0, null);

  image = op.filter(image, null);

  // Create frame with specific title

  Frame frame = new Frame("Example Frame");

  // Add a component with a custom paint method

  frame.add(new CustomPaintComponent());

  // Display the frame

  int frameWidth = 300;

  int frameHeight = 300;

  frame.setSize(frameWidth, frameHeight);



     * To draw on the screen, it is first necessary to subclass a Component and
     * override its paint() method. The paint() method is automatically called
     * by the windowing system whenever component's area needs to be repainted.
    static class CustomPaintComponent extends Component {

  public void paint(Graphics g) {

// Retrieve the graphics context; this object is used to paint

// shapes

Graphics2D g2d = (Graphics2D) g;


 * Draw an Image object The coordinate system of a graphics context

 * is such that the origin is at the northwest corner and x-axis

 * increases toward the right while the y-axis increases toward the

 * bottom.


int x = 0;

int y = 0;

g2d.drawImage(image, x, y, this);




This was an example on how to Brighten or Darken an RGB Image in Java.

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