static Area actuallyVisibleComponentArea(Component c) {
  ret c == null ? null : swing(func -> Area {
    Area area = new Area(0, 0, new Rectangle(getWidth(c), getHeight(c)));
    Container parent = c.getParent();
    if (parent == null) ret area;
    for (Component peer : componentsSortedByZOrder(getChildren(parent))) {
      if (peer = c) break;
      area.subtract(peer.getBounds());
    }
    Area parentArea = actuallyVisibleComponentArea(parent);
    parentArea.transform(AffineTransform.getTranslateInstance(-c.getX(), -c.getY()));
    area.intersect(parentArea);
    ret area;
  });
}