'on mouse motion draw the cursor if visible'

def onmove(self, event):

    if self.ignore(event):
        return
    if (not self.canvas.widgetlock.available(self)):
        return
    if (event.inaxes != self.ax):
        self.linev.set_visible(False)
        self.lineh.set_visible(False)
        if self.needclear:
            self.canvas.draw()
            self.needclear = False
        return
    self.needclear = True
    if (not self.visible):
        return
    self.linev.set_xdata((event.xdata, event.xdata))
    self.lineh.set_ydata((event.ydata, event.ydata))
    self.linev.set_visible((self.visible and self.vertOn))
    self.lineh.set_visible((self.visible and self.horizOn))
    self._update()
