Swing/VerticalColumnTableHeader のバックアップ(No.1)

class VerticalTableHeaderRenderer implements TableCellRenderer {
  private static final String ASCENDING = "Table.ascendingSortIcon";
  private static final String DESCENDING = "Table.descendingSortIcon";
  private final Icon ascendingIcon;
  private final Icon descendingIcon;
  private final EmptyIcon emptyIcon = new EmptyIcon();
  private final JPanel intermediate = new JPanel();
  private final JLabel label = new JLabel("", null, SwingConstants.LEADING);

  protected VerticalTableHeaderRenderer() {
    ascendingIcon = UIManager.getLookAndFeelDefaults().getIcon(ASCENDING);
    descendingIcon = UIManager.getLookAndFeelDefaults().getIcon(DESCENDING);
    emptyIcon.width = ascendingIcon.getIconWidth();
    emptyIcon.height = ascendingIcon.getIconHeight();
  }

  @Override public Component getTableCellRendererComponent(
      JTable table, Object value, boolean isSelected, boolean hasFocus,
      int row, int column) {
    UIManager.put(ASCENDING, emptyIcon);
    UIManager.put(DESCENDING, emptyIcon);
    TableCellRenderer r = table.getTableHeader().getDefaultRenderer();
    Component c = r.getTableCellRendererComponent(
      table, value, isSelected, hasFocus, row, column);
    UIManager.put(ASCENDING, ascendingIcon);
    UIManager.put(DESCENDING, descendingIcon);
    if (c instanceof JLabel) {
      JLabel l = (JLabel) c;
      l.setHorizontalAlignment(SwingConstants.CENTER);
      SortOrder sortOrder = getColumnSortOrder(table, column);
      Icon sortIcon;
      switch (sortOrder) {
        case ASCENDING:
          sortIcon = ascendingIcon;
          break;
        case DESCENDING:
          sortIcon = descendingIcon;
          break;
        default: // case UNSORTED:
          sortIcon = emptyIcon;
          break;
      }
      label.setText(l.getText());
      label.setIcon(new RotateIcon(sortIcon, 90));
      label.setHorizontalTextPosition(SwingConstants.LEFT);
      label.setBorder(BorderFactory.createEmptyBorder(0, 2, 0, 2));
      // l.setIcon(new RotateIcon(new ComponentIcon(label), -90));
      l.setIcon(makeVerticalHeaderIcon(label));
      l.setText(null);
    }
    return c;
  }

  public static SortOrder getColumnSortOrder(JTable table, int column) {
    SortOrder rv = SortOrder.UNSORTED;
    if (table != null && table.getRowSorter() != null) {
      List<? extends RowSorter.SortKey> sortKeys =
        table.getRowSorter().getSortKeys();
      int mi = table.convertColumnIndexToModel(column);
      if (!sortKeys.isEmpty() && sortKeys.get(0).getColumn() == mi) {
        rv = sortKeys.get(0).getSortOrder();
      }
    }
    return rv;
  }

  private Icon makeVerticalHeaderIcon(Component label) {
    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 = AffineTransform.getTranslateInstance(0, h);
    at.quadrantRotate(-1);
    g2.setTransform(at);
    SwingUtilities.paintComponent(g2, label, intermediate, 0, 0, h, w);
    g2.dispose();
    return new ImageIcon(bi);
  }
}