import unittest
import pytest
from shapely.geometry.polygon import LinearRing, Polygon, orient, signed_area
class SignedAreaTestCase(unittest.TestCase):
def test_triangle(self):
tri = LinearRing([(0, 0), (2, 5), (7, 0)])
assert signed_area(tri) == pytest.approx(-7 * 5 / 2)
def test_square(self):
xmin, xmax = (-1, 1)
ymin, ymax = (-2, 3)
rect = LinearRing(
[(xmin, ymin), (xmax, ymin), (xmax, ymax), (xmin, ymax), (xmin, ymin)]
)
assert signed_area(rect) == pytest.approx(10.0)
class RingOrientationTestCase(unittest.TestCase):
def test_ccw(self):
ring = LinearRing([(1, 0), (0, 1), (0, 0)])
assert ring.is_ccw
def test_cw(self):
ring = LinearRing([(0, 0), (0, 1), (1, 0)])
assert not ring.is_ccw
class PolygonOrienterTestCase(unittest.TestCase):
def test_no_holes(self):
ring = LinearRing([(0, 0), (0, 1), (1, 0)])
polygon = Polygon(ring)
assert not polygon.exterior.is_ccw
polygon = orient(polygon, 1)
assert polygon.exterior.is_ccw
def test_holes(self):
# fmt: off
polygon = Polygon(
[(0, 0), (0, 1), (1, 0)],
[[(0.5, 0.25), (0.25, 0.5), (0.25, 0.25)]]
)
# fmt: on
assert not polygon.exterior.is_ccw
assert polygon.interiors[0].is_ccw
polygon = orient(polygon, 1)
assert polygon.exterior.is_ccw
assert not polygon.interiors[0].is_ccw