import unittest
import pytest
from shapely.geometry import LinearRing, LineString
from shapely.testing import assert_geometries_equal
@pytest.mark.parametrize("distance", [float("nan"), float("inf")])
def test_non_finite_distance(distance):
g = LineString([(0, 0), (10, 0)])
with pytest.raises(ValueError, match="distance must be finite"):
g.parallel_offset(distance)
class OperationsTestCase(unittest.TestCase):
def test_parallel_offset_linestring(self):
line1 = LineString([(0, 0), (10, 0)])
left = line1.parallel_offset(5, "left")
assert_geometries_equal(left, LineString([(0, 5), (10, 5)]))
right = line1.parallel_offset(5, "right")
assert_geometries_equal(right, LineString([(10, -5), (0, -5)]), normalize=True)
right = line1.parallel_offset(-5, "left")
assert_geometries_equal(right, LineString([(10, -5), (0, -5)]), normalize=True)
left = line1.parallel_offset(-5, "right")
assert_geometries_equal(left, LineString([(0, 5), (10, 5)]))
# by default, parallel_offset is right-handed
assert_geometries_equal(line1.parallel_offset(5), right)
line2 = LineString([(0, 0), (5, 0), (5, -5)])
assert_geometries_equal(
line2.parallel_offset(2, "left", join_style=3),
LineString([(0, 2), (5, 2), (7, 0), (7, -5)]),
)
assert_geometries_equal(
line2.parallel_offset(2, "left", join_style=2),
LineString([(0, 2), (7, 2), (7, -5)]),
)
# offset_curve alias
assert_geometries_equal(
line1.offset_curve(2, quad_segs=10),
line1.parallel_offset(2, "left", resolution=10),
)
assert_geometries_equal(
line1.offset_curve(-2, join_style="mitre"),
line1.parallel_offset(2, "right", join_style=2),
)
def test_parallel_offset_linear_ring(self):
lr1 = LinearRing([(0, 0), (5, 0), (5, 5), (0, 5), (0, 0)])
assert_geometries_equal(
lr1.parallel_offset(2, "left", resolution=1),
LineString([(2, 2), (3, 2), (3, 3), (2, 3), (2, 2)]),
)
# offset_curve alias
assert_geometries_equal(
lr1.offset_curve(2, quad_segs=1),
lr1.parallel_offset(2, "left", resolution=1),
)