'return the extent of the artist. The extent of the child
added with the pad is returned'

def get_extent(self, renderer):

    (w, h, xd, yd) = self.get_child().get_extent(renderer)
    fontsize = renderer.points_to_pixels(self.prop.get_size_in_points())
    pad = (self.pad * fontsize)
    return ((w + (2 * pad)), (h + (2 * pad)), (xd + pad), (yd + pad))
