def _draw_circle(data, obj, draw_options):
    """Return the PGFPlots code for circles.
    """
    x, y = obj.center
    ff = data['float format']
    cont = ('\\draw[{}] (axis cs:' + ff + ',' + ff + ') circle (' + ff + ');\n'
        ).format(','.join(draw_options), x, y, obj.get_radius())
    return data, cont
