def delta(self):
		"""The delta between the last event and the current event.

		For gesture events that are not of type
		:attr:`~libinput.constant.EventType.GESTURE_SWIPE_UPDATE` or
		:attr:`~libinput.constant.EventType.GESTURE_PINCH_UPDATE`, this
		property raises :exc:`AttributeError`.

		If a device employs pointer acceleration, the delta returned by this
		property is the accelerated delta.

		Relative motion deltas are normalized to represent those of a device
		with 1000dpi resolution. See `Normalization of relative motion`_
		for more details.

		Returns:
			(float, float): The relative (x, y) movement since the last event.
		"""

		if self.type not in {EventType.GESTURE_SWIPE_UPDATE,
				EventType.GESTURE_PINCH_UPDATE}:
			raise AttributeError(_wrong_prop.format(self.type))
		delta_x = self._libinput.libinput_event_gesture_get_dx(self._handle)
		delta_y = self._libinput.libinput_event_gesture_get_dy(self._handle)
		return delta_x, delta_y