def test_gives_correct_area_scaling(self):
polygon = np.array([
(-3, -2),
(-1, 4),
(6, 1),
(3, 10),
(-4, 9),
])
cx, cy = poly.center_of_polygon(polygon)
res = poly.scale_polygon(polygon, 2.0)
exp = np.array([
(-6.36666667, -9.5333333),
(-2.36666667, 2.4666667),
(11.63333333, -3.5333333),
(5.63333333, 14.4666667),
(-8.36666667, 12.4666667),
])
np.testing.assert_almost_equal(res, exp)
rx, ry = poly.center_of_polygon(res)
self.assertAlmostEqual(rx, cx)
self.assertAlmostEqual(ry, cy)
area = poly.area_of_polygon(res)
self.assertEqual(area, 240)
def test_gives_correct_center_circle(self):
theta = np.linspace(0, 2*np.pi, 50)
polygon = np.stack([
np.cos(theta) + 5,
np.sin(theta) - 1,
], axis=1)
cx, cy = poly.center_of_polygon(polygon)
np.testing.assert_almost_equal(cx, 5, decimal=3)
np.testing.assert_almost_equal(cy, -1, decimal=3)
def test_gives_correct_center_evenly_sampled(self):
# It's a square... so center is -1, +1
polygon = np.array([
(-4, -2),
(-4, 4),
(2, 4),
(2, -2),
])
cx, cy = poly.center_of_polygon(polygon)
self.assertEqual(cx, -1)
self.assertEqual(cy, 1)
def test_gives_correct_center_counter_clockwise(self):
polygon = np.array([
(2, -2),
(2, 4),
(1, 4),
(-1, 4),
(-2, 4),
(-3, 4),
(-4, 4),
(-4, -2),
])
cx, cy = poly.center_of_polygon(polygon)
self.assertEqual(cx, -1)
self.assertEqual(cy, 1)
def test_gives_correct_center_clockwise(self):
# It's a square... so center is -1, +1
# BUUUT, we have extra samples along the line from x=(-4 to +2)
polygon = np.array([
(-4, -2),
(-4, 4),
(-3, 4),
(-2, 4),
(-1, 4),
(1, 4),
(2, 4),
(2, -2),
])
cx, cy = poly.center_of_polygon(polygon)
self.assertEqual(cx, -1)
self.assertEqual(cy, 1)