Paint JMenuItem selection rollover with rounded rectangle

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

Code

class BasicRoundMenuItemUI extends BasicMenuItemUI {
  @Override protected void paintBackground(
      Graphics g, JMenuItem menuItem, Color bgColor) {
    ButtonModel m = menuItem.getModel();
    Color oldColor = g.getColor();
    int menuWidth = menuItem.getWidth();
    int menuHeight = menuItem.getHeight();
    if (menuItem.isOpaque()) {
      if (m.isArmed() || (menuItem instanceof JMenu && m.isSelected())) {
        Graphics2D g2 = (Graphics2D) g.create();
        g2.setRenderingHint(
          RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        // g2.clearRect(0, 0, menuWidth, menuHeight);
        g2.setPaint(menuItem.getBackground());
        g2.fillRect(0, 0, menuWidth, menuHeight);
        g2.setColor(bgColor);
        g2.fillRoundRect(2, 2, menuWidth - 4, menuHeight - 4, 8, 8);
        g2.dispose();
      } else {
        g.setColor(menuItem.getBackground());
        g.fillRect(0, 0, menuWidth, menuHeight);
      }
      g.setColor(oldColor);
    } else if (m.isArmed() || (menuItem instanceof JMenu && m.isSelected())) {
      g.setColor(bgColor);
      g.fillRoundRect(2, 2, menuWidth - 4, menuHeight - 4, 8, 8);
      g.setColor(oldColor);
    }
  }
}

References

• Paint JMenuItem selection rollover with rounded rectangle(Japanese)