JTabbedPaneのタブタイトル文字列を回転して縦組表示する

private Icon makeVerticalTabIcon(String title, Icon icon, boolean clockwise) {
  JLabel label = new JLabel(title, icon, SwingConstants.LEADING);
  label.setBorder(BorderFactory.createEmptyBorder(0, 2, 0, 2));
  Dimension d = label.getPreferredSize();
  int w = d.height;
  int h = d.width;
  BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
  Graphics2D g2 = (Graphics2D) bi.getGraphics();
  AffineTransform at = clockwise
      ? AffineTransform.getTranslateInstance(w, 0)
      : AffineTransform.getTranslateInstance(0, h);
  at.quadrantRotate(clockwise ? 1 : -1);
  g2.setTransform(at);
  SwingUtilities.paintComponent(g2, label, this, 0, 0, d.width, d.height);
  g2.dispose();
  return new ImageIcon(bi);
}