'Add a cursor to *ax*.  If ``useblit=True``, use the backend-
dependent blitting features for faster updates (GTKAgg
only for now).  *lineprops* is a dictionary of line properties.'

def __init__(self, ax, horizOn=True, vertOn=True, useblit=False, **lineprops):

    AxesWidget.__init__(self, ax)
    self.connect_event(u'motion_notify_event', self.onmove)
    self.connect_event(u'draw_event', self.clear)
    self.visible = True
    self.horizOn = horizOn
    self.vertOn = vertOn
    self.useblit = (useblit and self.canvas.supports_blit)
    if self.useblit:
        lineprops[u'animated'] = True
    self.lineh = ax.axhline(ax.get_ybound()[0], visible=False, **lineprops)
    self.linev = ax.axvline(ax.get_xbound()[0], visible=False, **lineprops)
    self.background = None
    self.needclear = False
