How to extract an image from a canvas ?

Question

Hello there,
I have a picture loaded in a Canvas, and I would like to save it to a file.
Here's what I have:
NireCanvas can = new NireCanvas();
back_image = JAI.create("fileload","c:\\inaxio\\Default.jpg");
buf_back = back_image.getAsBufferedImage();
public class NireCanvas extends Canvas
public void paint(Graphics g)
          Graphics2D g2d = (Graphics2D)g;
          g.drawImage(buf_back,0,0,null);
public void button_save_imagen_click()
     try{
          Rectangle r = can.getBounds();
          Image img = can.createImage(r.width,r.height);
          Graphics g = img.getGraphics();
          ImageIO.write((RenderedImage)img, "png", new File("c:\\temp.png"));
     } catch(Exception err){System.out.println("arazoa gordetzereakoan.");}
the back_image is displayed on the canvas correctly, but when I try to get the image, all I get is a plain png image, which has the same size of the canvas and the same color of the canvas but without the picture (it's grey).
I display the img on another frame, and the img is grey too.
I think that something is missing in my code. I have tried lots of things and always with the same result. Does somebody know what I'm doing wrong ?
thanx for helping! inaxio

Answer 1

Rectangle r = can.getBounds();
Image img = can.createImage(r.width,r.height);
ImageIO.write((RenderedImage)img, "png", new File("c:\\temp.png"));That code creates a new blank image and saves it to a file. That's whats wrong. Shouldn't buf_back be used in there somewhere? The fact that it is present in paint() doesn't help in this context.