code: def on_mouse_motion(self, x, y, dx, dy):
          
          # Screen coordinates relative to the lower-left corner
          # so we have to flip the y axis to make this consistent with
          # other window libraries
          self.example.mouse_position_event(x, self.buffer_height - y)
docs: Pyglet specific mouse motion callback.
          Forwards and traslates the event to the example