Hi Newsgroup!

I need to create an image from a JPanel, that has not been displayed
on the screen. I.e. I recieve a JPanel and want to pass it as image to
a library without showing the JPanel to the user.
My idea is to do something like this:

public void doSomething(JPanel originalPanel) {
    testImage(getImage(originalPanel));
}

public Image getImage(JPanel aPanel) {
    Image image = aPanel.createImage(aPanel.getWidth(),
aPanel.getHeight());
    return image;
}

public void testImage(Image aImage) {
    JFrame frame = new JFrame("testImage");
    JLabel label = new JLabel(new ImageIcon(aImage));
    frame.getContentPane().add(label);
    frame.pack();
    frame.setVisible(true);
}

But this gives a:
java.lang.NullPointerException
    at javax.swing.ImageIcon.<init>(Unknown Source)

because the Image returned by getImage() is null.
Has anybody some suggestions how to get an image object from a panel
that hasn't been displayed?

Thx

Norbert