AffineTransform problem caused by JMenuBar + JTabbedPane

Question

Hello everyone.
I am starting to think that there is a bug in Java, because otherwise what else could cause the problem I am experiencing? Namely: adding a panel with a vertical text (like a Y axis caption) using an AffineTransform (see SSCCE below) causes this text to be misplaced in some cases.
Variant A
Panel is added directly to the application frame. This causes no problems and everything is as it should be.
Variant B
Panel is placed on a tabbed pane and a menu bar is associated with the frame. The vertical text is now shifted away from the place where it should be by the height of the menu bar plus the height of tabs on the tabbed pane. Why is this happening? Am I doing something wrong?
Moreover, when one switches to another tab and then back, the text is now shifted only by the height of the tabs. Once the application window is resized at least a bit, the text jumps right back to the position shifted by tab height plus menu bar height... Strange, strange, strange...
SSCCE
import java.awt.*;
import java.awt.font.FontRenderContext;
import java.awt.geom.*;
import javax.swing.*;
class MyPanel extends JPanel {
    MyPanel() {
        this.setPreferredSize(new Dimension(300, 200));
    @Override
    protected void paintComponent(Graphics g) {
        Graphics2D g2D = (Graphics2D)g;
        int g2DWidth = this.getWidth();
        int g2DHeight = this.getHeight();
        // Horizontal line in the middle of the panel (indicates the position
        // where the middle of the vertical label should be)
        g2D.drawLine(30, (int)(g2DHeight / 2), g2DWidth - 10,
                (int)(g2DHeight / 2));
        // Vertical label
        AffineTransform origTransform = g2D.getTransform();
        AffineTransform rotate = AffineTransform.getRotateInstance(
                -Math.PI / 2.0, 0, 0);
        g2D.setTransform(rotate);
        String text = "Centered?";
        FontRenderContext frc = g2D.getFontRenderContext();
        Font font = UIManager.getFont("Label.font");
        Rectangle2D bounds = font.getStringBounds(text, frc);
        g2D.drawString(text, -(int)((g2DHeight + bounds.getWidth()) / 2), 20);
        g2D.setTransform(origTransform);
class Main {
    private static void createAndShowGUI() {
        // Menu bar
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Menu");
        JMenuItem menuItem = new JMenuItem("Menu Item");
        menu.add(menuItem);
        menuBar.add(menu);
        // Tabbed pane
        JTabbedPane tabbedPane = new JTabbedPane();
        JPanel panel = new MyPanel();
        tabbedPane.add(panel);
        JLabel label = new JLabel("Nothing interesting's going on here...");
        tabbedPane.add(label);
        // Frame
        JFrame frame = new JFrame();
        // TRICKY PART HERE =========================================
        // [(Un)comment lines as necessary]
        // Variant A: the panel only --------------------------------
        //frame.add(panel);
        // Variant B: menu bar + panel on a tabbed pane -------------
        frame.setJMenuBar(menuBar);
        frame.add(tabbedPane);
        // ==========================================================
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}Thanks for any help.
Best regards,
vt
Edited by: -vt- on 23-Apr-2010 13:08

Answer 1

You are ignoring the current transform on the Graphics, use the following instead of setTransform():
g2D.rotate(-Math.PI / 2.0, 0, 0);