public Rectangle2D getBounds(Iterable<?> objects) {
Rectangle2D.Double bounds = new Rectangle2D.Double();
for (Object o : objects) {
if (o instanceof Grob) {
Grob grob = (Grob) o;
bounds.add(grob.getBounds().getRectangle2D());
} else if (o instanceof Iterable) {
bounds.add(getBounds((Iterable<?>) o));
}
}
// Make sure the width and height or greater than zero.