'Draw an ellipse the size in data coordinate of the give axes.
pad, borderpad in fraction of the legend font size (or prop)'

def __init__(self, transform, width, height, angle, loc, pad=0.1, borderpad=0.1, prop=None, frameon=True):

    self._box = AuxTransformBox(transform)
    self.ellipse = Ellipse((0, 0), width, height, angle)
    self._box.add_artist(self.ellipse)
    AnchoredOffsetbox.__init__(self, loc, pad=pad, borderpad=borderpad, child=self._box, prop=prop, frameon=frameon)
