Draw On Panel/Save as GIF problem

Question

Hi everyone,
I am designing an application where the user should be able to free draw on a JPanel(that resides on a JFrame) by licking/dragging/releasing the mouse.
Then, this drawing needs to be saved as a GIF image.
OK. I have managed to implement a free-draw algorithm but now I am having problems saving the GIF. I think I kinda know where the the problem is, but I can't find any ways around it.
I am using a Graphics2D class to draw the lines, and I am using the .setClip method to assossiate my graphics object to the JPanel,i.e.
g.setClip(jPanel1.getX(), jPanel1.getY(), jPanel1.getWidth(), jPanel1.getHeight());
I think that this is where the problem is. I believe that eventhough I can actually see the line drawn by the user @ runtime, the line itself is not "added" onto the JPanel, it just draws itself onto the area that the JPanel occupies.
Hence, when I attempt to save the JPanel as a GIF(using an Acme.JPM.Encoder), the saved image appears monochrome, without any lines on it at all.
The free-draw algorithm that i am using involes saving all the coordinates of the area where the mouse is being dragged into a Vector of Points which I have to repaint() whenever a new drag is listened.
Any help would be greatly appreciated,
thanks
Yiannis

Answer 1

Hi Ashwin,
I have created a class that can take a JPanel and save it into GIF.
the code is:
import javax.swing.*;
import java.io.*;
import java.awt.image.*;
import java.awt.Graphics;
import Acme.JPM.Encoders.*;
public class saveToGIF {
private JPanel panel;
/** Creates a new instance of saveToGIF */
public saveToGIF(JPanel panel, String file) throws IOException{
this.panel=panel;
BufferedImage image = new BufferedImage(this.panel.getWidth(), this.panel.getHeight, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
panel.paint(g);
FileOutputStream fos = new FileOutputStream(file);
GifEncoder encoder = new GifEncoder(image, fos);
encoder.encode();
fos.close();
OK, this works fine. However, I cannot add my drawings onto the JPanel.
Sth with overwritting the paintComponent() method is what i do no fully nderstand.
Thanks,
Yiannis