Double Scroll Bars, Side By Side, End To End, In A JScrollPane

Question

I'm trying to create double scroll bars next to each other, end to end. One scroll bar is for the position in the grid, while the other, smaller scroll bar controls the zoom level. I am masquerading a JPanel as a JScrollBar. I'm adding two scroll bars to the panel, and encapsulating the panel in a subclass of JScrollBar. You might wonder why I would do that. Because JScrollPane only accepts JScrollBar classes in setHorizontalScrollBar() and setVerticalScrollBar(). I tried to override every painting method I could think of that was important, but when I test it, nothing is shown. It is completely blank. Here is the code below. I know I still have to override the general JScrollBar methods and pass them to the primary scrollbar. Does anyone have any ideas on how to do somethink like I am attempting to do?
import java.awt.*;
import javax.swing.*;
import java.lang.reflect.*;
* <p>Title: </p>
* <p>Description: This class masquerades as a JScrollBar, but it wraps two scrollbars next to each other. The
* main scrollbar, and the secondary scrollbar which is smaller. Any calls which treat this as a regular scrollbar
* will return the main scrollbar's values, while the special methods can be used to return the seondary scrollbar's
* values.
* </p>
* <p>Copyright: Copyright (c) 2003</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
public class DoubleScrollBar extends JScrollBar {
  JPanel panel = new JPanel();
  JScrollBar primary;
  JScrollBar secondary;
  public DoubleScrollBar(int orientation) {
    init(orientation);
  void init() {
    panel.setLayout(new GridBagLayout());
    if ( orientation == JScrollBar.HORIZONTAL ) {
      primary = new JScrollBar(JScrollBar.HORIZONTAL);
      secondary = new JScrollBar(JScrollBar.HORIZONTAL);
      GridBagConstraints gbc = new GridBagConstraints(0, 0, 1, 1, 0.75, 0.0,
          GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL, new Insets(0, 0, 0, 0), 0, 0);
      panel.add(primary, gbc);
      gbc.gridx = 1;
      gbc.weightx = 0.25;
      gbc.anchor = GridBagConstraints.EAST;
      panel.add(secondary, gbc);
    } else if ( orientation == JScrollBar.VERTICAL ) {
      primary = new JScrollBar(JScrollBar.VERTICAL);
      secondary = new JScrollBar(JScrollBar.VERTICAL);
      GridBagConstraints gbc = new GridBagConstraints(0, 0, 1, 1, 0.0, 0.75,
          GridBagConstraints.NORTH, GridBagConstraints.VERTICAL, new Insets(0, 0, 0, 0), 0, 0);
      panel.add(primary, gbc);
      gbc.gridy = 1;
      gbc.weighty = 0.25;
      gbc.anchor = GridBagConstraints.SOUTH;
      panel.add(secondary, gbc);
  public Dimension getPreferredSize() {
    return panel.getPreferredSize();
  public void setPreferredSize(Dimension d) {
    panel.setPreferredSize(d);
  public Dimension getSize() {
    return panel.getSize();
  public void paint(Graphics g) {
    panel.paint(g);
  public void paintAll(Graphics g) {
    panel.paintAll(g);
  protected void paintComponent(Graphics g) {
    try {
      Method m = panel.getClass().getMethod("paintComponent", new Class[] {Graphics.class});
      m.invoke(panel, new Object[] {g});
    catch (SecurityException ex) {
      System.out.println("SecurityException");
    catch (NoSuchMethodException ex) {
      System.out.println("NoSuchMethodException");
    catch (InvocationTargetException ex1) {
      System.out.println("InvocationTargetException");
    catch (IllegalArgumentException ex1) {
      System.out.println("IllegalArgumentException");
    catch (IllegalAccessException ex1) {
      System.out.println("IllegalAccessException");
  public void paintComponents(Graphics g) {
    panel.paintComponents(g);
  public void repaint(long tm, int x, int y, int w, int h) {
    if ( panel != null ) {
      panel.repaint(tm, x, y, w, h);
  public int getWidth() {
    return panel.getWidth();
  public int getHeight() {
    return panel.getHeight();
  public static void main(String[] args) {
    JFrame f = new JFrame();
    DoubleScrollBar dsb = new DoubleScrollBar(JScrollBar.HORIZONTAL);
    dsb.setPreferredSize(new Dimension(200, 50));
    f.getContentPane().add(dsb);
    f.pack();
    f.show();

Answer 1

I know this isn't zooming, but maybe it will help.import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Test3 extends JFrame {
  MyPanel mp = new MyPanel();
  public Test3() {
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container content = getContentPane();
    JScrollBar jsb = new JScrollBar();
    jsb.addAdjustmentListener(new AdjustmentListener() {
      public void adjustmentValueChanged(AdjustmentEvent ae) {
        mp.setSize(ae.getValue()*5);
    content.add(jsb, BorderLayout.EAST);
    mp.setPreferredSize(new Dimension(500,500));
    content.add(new JScrollPane(mp), BorderLayout.CENTER);
    setSize(300, 300);
  public static void main(String[] args) { new Test3().setVisible(true); }
class MyPanel extends JPanel {
  int size;
  public void paintComponent(Graphics g) {
    super.paintComponent(g);
    g.setColor(Color.red);
    g.drawRect(10,10,size,size);
  public void setSize(int size) {
    this.size=size;
    repaint();
}