Recording gestures – line, circle, and cross

What about drawing with one finger? Can we recognize gestures? It is possible to do this with Kivy. First, we need to record the gestures that we want to use. A gesture is represented as a long string that contains the points of a stroke over the screen. The following code uses the Kivy Gesture and GestureDatabase classes to record gesture strokes. It can be run with Python gesturerecorder.py:

180. # File Name: gesturerecorder.py
181. from kivy.app import App
182. from kivy.uix.floatlayout import FloatLayout
183. from kivy.graphics import Line, Ellipse
184. from kivy.gesture import Gesture, GestureDatabase
185. 
186. class GestureRecorder(FloatLayout):
187. 
188.     def on_touch_down(self, touch):
189.         self.points = [touch.pos]
190.         with self.canvas:
191.             Ellipse(pos=(touch.x-5,touch.y-5),size=(10,10))
192.             self.Line = Line(points=(touch.x, touch.y))
193. 
194.     def on_touch_move(self, touch):
195.  ...