def test_constructor_errors():
with pytest.raises(AssertionError):
Line('not a point', Point(1, 0))
with pytest.raises(AssertionError):
Line(Point(0, 0), 'not a point')
with pytest.raises(AssertionError):
Line(Point(1, 0), Point(1, 0))
def test_intersection_errors():
with pytest.raises(AssertionError):
line.intersection(
'not a line',
Line(Point(0, 0), Point(1, 0)),
)
with pytest.raises(AssertionError):
line.intersection(
Line(Point(0, 0), Point(1, 0)),
'not a line',
)
def circumcenter(triangle):
assert isinstance(triangle, Triangle)
# translate to origin
t_a = triangle.a - triangle.c
t_b = triangle.b - triangle.c
# compute points on perpendicular bisectors
pb_a_1 = Point.scale(t_a, 0.5)
pb_a_2 = pb_a_1 + Point(t_a.y, -t_a.x)
pb_b_1 = Point.scale(t_b, 0.5)
pb_b_2 = pb_b_1 + Point(t_b.y, -t_b.x)
# find intersection of bisectors
trans_circumcenter = line.intersection(
Line(pb_a_1, pb_a_2),
Line(pb_b_1, pb_b_2),
)
# if intersection not found, that indicates the triangle was degenerate
assert trans_circumcenter is not None
# un-translate result
return trans_circumcenter + triangle.c
def intersection(line_1, line_2):
# based on the solution provided on this wikipedia article:
# https://en.wikipedia.org/wiki/Line%E2%80%93line_intersection#Given_two_points_on_each_line
assert isinstance(line_1, Line)
assert isinstance(line_2, Line)
interm_a = (line_1.a.x * line_1.b.y) - (line_1.a.y * line_1.b.x)
interm_b = (line_2.a.x * line_2.b.y) - (line_2.a.y * line_2.b.x)
interm_c = line_1.a.x - line_1.b.x
interm_d = line_2.a.x - line_2.b.x
interm_e = line_1.a.y - line_1.b.y
interm_f = line_2.a.y - line_2.b.y
denom = (interm_c * interm_f) - (interm_d * interm_e)
if denom == 0:
return None
return Point(
((interm_a * interm_d) - (interm_b * interm_c)) / denom,
((interm_a * interm_f) - (interm_b * interm_e)) / denom,
)
line.intersection(
'not a line',
Line(Point(0, 0), Point(1, 0)),
)
with pytest.raises(AssertionError):
line.intersection(
Line(Point(0, 0), Point(1, 0)),
'not a line',
)
@pytest.mark.parametrize(
('line_1', 'line_2', 'expected'),
[
(Line(Point(2, 0), Point(1, 0)), Line(Point(-1, -1), Point(
-2, -2)), Point(0, 0)), # intersect; horizontal x diagonal
(Line(Point(0, 2), Point(0, 1)), Line(Point(-1, -1), Point(
-2, -2)), Point(0, 0)), # intersect; vertical x diagonal
(Line(Point(1, 1), Point(2, 2)), Line(Point(1, -1), Point(
2, -2)), Point(0, 0)), # intersect; diagonal x diagonal 1
(Line(Point(0, 0), Point(6, 10)), Line(Point(0, 2), Point(
-3, -1)), Point(3, 5)), # intersect; diagonal x diagonal 2
(Line(Point(1, 1), Point(2, 2)), Line(Point(3, 1), Point(
4, 2)), None), # parallel; diagonal
(Line(Point(0, 1), Point(1, 1)), Line(Point(0, 3), Point(
1, 3)), None), # parallel; horizontal
(Line(Point(1, 1), Point(1, 2)), Line(Point(3, 1), Point(
3, 2)), None), # parallel; vertical
(Line(Point(0, 1), Point(0, 2)), Line(Point(0, 3), Point(
0, 4)), None), # coinciding lines
def test_point_scale(p, c, expected):
assert Point.scale(p, c) == expected
def test_sub_type_match():
with pytest.raises(AssertionError):
Point(0, 0) - 'not a point'
import pytest
from src.geo.point import Point
@pytest.mark.parametrize(('p1', 'p2', 'expected'), [
(Point(0, 0), Point(0, 0), True),
(Point(1, 0), Point(1, 0), True),
(Point(0, 1), Point(0, 1), True),
(Point(1, 1), Point(1, 1), True),
(Point(5, 3), Point(5, 3), True),
(Point(-5, -3), Point(-5, -3), True),
(Point(1, 0), Point(0, 0), False),
(Point(0, 1), Point(0, 0), False),
(Point(0, 0), Point(1, 0), False),
(Point(0, 0), Point(0, 1), False),
(Point(5, 0), Point(3, 0), False),
(Point(0, 5), Point(0, 3), False),
(Point(1, 0), Point(-1, 0), False),
(Point(0, 1), Point(0, -1), False),
(Point(0, 0), 'Not a point', False),
])
def test_point_eq(p1, p2, expected):
assert (p1 == p2) == expected
assert (p2 == p1) == expected
assert (p1 != p2) == (not expected)
assert (p2 != p1) == (not expected)
@pytest.mark.parametrize(('p1', 'p2', 'expected'), [
(Point(0, 0), Point(0, 0), Point(0, 0)),
def test_circumcenter_errors():
with pytest.raises(AssertionError):
triangle.circumcenter('not a triangle')
with pytest.raises(AssertionError):
triangle.circumcenter(Triangle(Point(0, 0), Point(1, 0), Point(2, 0)))
Point( 0, 0),
'not a point',
Point( 1, 0),
)
with pytest.raises(AssertionError):
Triangle(
Point( 0, 0),
Point( 1, 0),
'not a point',
)
@pytest.mark.parametrize(
('t', 'expected'), [
( Triangle(Point( 2, 0), Point( 0, 2), Point( 0, 0)),
Point( 1, 1) ), # right triangle at origin
( Triangle(Point(-1, 2), Point( 1, 2), Point( 0, 0)),
Point( 0, 1.25) ), # acute triangle at origin
( Triangle(Point(-2, 1), Point( 2, 1), Point( 0, 0)),
Point( 0, 2.5) ), # obtuse triangle at origin
( Triangle(Point( 1, -3), Point(-1, -1), Point(-1, -3)),
Point( 0, -2) ), # right triangle translated
( Triangle(Point( 3, 7), Point( 5, 7), Point( 4, 5)),
Point( 4, 6.25) ), # acute triangle translated
( Triangle(Point( 5, 1), Point( 9, 1), Point( 7, 0)),