I wrote a little bit of code to read pixel data for you. The image I used is the jGuru logo on the upper left of this page. I downloaded it and put it in the same directory as the following class. Normally I use packages and such, but for this simple example I crammed everything together in one class. Sorry if it is messy.

Note that this code sample should be tweaked to get alpha levels of images and such -- right now it only works for RGB BufferedImages.

The technique I used is this:

1. Load an image, draw it onto a BufferedImage

2. Get the Raster of the BufferedImage

3. Use a static Raster method to get pixel information.

4. Display the data to the screen.

/**
 * @author  Jon Morton
 */

import java.awt.*;
import java.awt.image.*;

public class RasterTool {

    Raster raster;
    BufferedImage image;
    
    /** Creates new RasterTool */
    public RasterTool(int x, int y) {
        // Loading an image relative in the same directory as this file.
        StringBuffer path = new StringBuffer(getClass().getResource("jguru.gif").getPath());
        // Using my own utility to load the image.
        Image jguru = loadImages(path.toString());
        // Creating a new BufferedImage to pick apart.
        image = new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);
        // Drawing the image into the buffer.
        image.getGraphics().drawImage(jguru, 0, 0, new Panel() );
        // Adding image data into a raster.
        raster = image.getData();
        // Call the function that gets pixel info.
        pixelInfo(x, y);
    }
    
    public void pixelInfo(int x, int y) {
        System.out.println("  Data: " + raster.getNumDataElements() );
        System.out.println(" Bands: " + raster.getNumBands() );
        System.out.println("Height: " + raster.getHeight() );
        int[] pixel = new int[3];
        raster.getPixel(x, y, pixel);
        System.out.println("   Red: "+ pixel[0] );
        System.out.println(" Green: "+ pixel[1] );
        System.out.println("  Blue: "+ pixel[2] );
    }
    
    public static void main(String[] args) {
        RasterTool t = new RasterTool(10,10);
    }

    // This is a function from one of my libraries that I use to load images.
    public static Image loadImages(String path) {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        MediaTracker tracker = new MediaTracker(new Panel());
        Image image = toolkit.getImage( path );
        try {
            tracker.addImage( image, 0 );
            tracker.waitForAll();
        } catch(InterruptedException ie) {
        }
        return image;
    }
    
}