Kivy: Line(circle) misaligned

circletest.py

import kivy
kivy.require('1.8.1')

from kivy.app import App
from kivy.lang import Builder

root = Builder.load_string('''
Widget:
    canvas:
        Color:
            rgba: 0, 0, 1, 1
        Line:
            points: 300, 100, 300, 500
        Color:
            rgba: 1, 1, 1, 1
        Line:
            circle: 300, 300, 100, 2, 182
''')

class TestApp(App):
    def build(self):
        return root

if __name__ == '__main__':
    TestApp().run()