Round the corners of JTableHeader

• download example.jar
• download src.zip
• repository

Code

class RoundedHeaderRenderer extends DefaultTableCellRenderer {
  private final JLabel firstLabel = new JLabel() {
    @Override public void paintComponent(Graphics g) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      g2.setPaint(getBackground());
      float r = 8f;
      float x = 0f;
      float y = 0f;
      float w = getWidth();
      float h = getHeight();
      Path2D p = new Path2D.Float();
      p.moveTo(x, y + r);
      p.quadTo(x, y, x + r, y);
      p.lineTo(x + w, y);
      p.lineTo(x + w, y + h);
      p.lineTo(x + r, y + h);
      p.quadTo(x, y + h, x, y + h - r);
      p.closePath();
      g2.fill(p);
      g2.dispose();
      super.paintComponent(g);
    }
  };
  private final JLabel lastLabel = new JLabel() {
    @Override public void paintComponent(Graphics g) {
      Graphics2D g2 = (Graphics2D) g.create();
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      g2.setPaint(getBackground());
      float r = 8f;
      float x = 0f;
      float y = 0f;
      float w = getWidth();
      float h = getHeight();
      Path2D p = new Path2D.Float();
      p.moveTo(x, y);
      p.lineTo(x + w - r, y);
      p.quadTo(x + w, y, x + w, y + r);
      p.lineTo(x + w, y + h - r);
      p.quadTo(x + w, y + h, x + w - r, y + h);
      p.lineTo(x, y + h);
      p.closePath();
      g2.fill(p);
      g2.dispose();
      super.paintComponent(g);
    }
  };

  public RoundedHeaderRenderer() {
    super();
    firstLabel.setOpaque(false);
    lastLabel.setOpaque(false);
    setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
    firstLabel.setBorder(BorderFactory.createEmptyBorder(0, 5, 0, 5));
    lastLabel.setBorder(BorderFactory.createEmptyBorder(0, 5, 0, 5));
  }

  @Override public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
    JLabel l = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
    if (column == 0) {
      l = firstLabel;
    } else if (column == table.getColumnCount() - 1) {
      l = lastLabel;
    }
    l.setFont(table.getFont());
    l.setText(value.toString());
    l.setForeground(table.getTableHeader().getForeground());
    l.setBackground(table.getTableHeader().getBackground());
    l.setHorizontalAlignment(SwingConstants.CENTER);
    return l;
  }
}

References

• Round the corners of JTableHeader(Japanese)