'Backend derived classes should call this function on any
motion-notify-event.
This method will call all functions connected to the
\'motion_notify_event\' with a :class:`MouseEvent` instance.
Parameters
x : scalar
the canvas coordinates where 0=left
y : scalar
the canvas coordinates where 0=bottom
guiEvent
the native UI event that generated the mpl event'

def motion_notify_event(self, x, y, guiEvent=None):

    (self._lastx, self._lasty) = (x, y)
    s = u'motion_notify_event'
    event = MouseEvent(s, self, x, y, self._button, self._key, guiEvent=guiEvent)
    self.callbacks.process(s, event)
