I cannot get a JScrollPane to allow me to scroll around inside a JViewport... I pasted two simplified classes below to demonstrate my point:
Running the WindowFrame class below shows a window and the image specified in the JViewer class but I am completely unable to scroll around the image. The JScrollBars are by default on DISPLAY_AS_NEEDED and the fact they do not appear shows that the program doesn't recognize that scrollbars are needed. Why is this?
-----------------------------------------
import javax.swing.*;

public class WindowFrame extends JFrame {
   
    JScrollPane scroller;
    JViewer view;
   
    public WindowFrame () {
        view = new JViewer();
        scroller = new JScrollPane(view);
        getContentPane().add(scroller);
        setSize(50,50);
        setTitle("This is not Scrollable!");
        show();
    }
   
    public static void main (String[] args) {
        new WindowFrame();
    }

}
---------------------------------------------------
import javax.swing.*;
import java.awt.*;

public class JViewer extends JViewport {

    public JViewer() {
    }
   
    public void paintComponent (Graphics g) {
        //I display the image offscreen (100,100) to                 //demonstrate that the scrollbars do not show up
        ImageIcon imageIcon =
        new ImageIcon(/*enter any image filepath here*/);

        g.drawImage(imageIcon.getImage(), 50,50, null);
    }   
}
-------------------------------------------------------------
Your help is much appreciated,
Mark