test_601_bulge.py

# Copyright (c) 2018 Manfred Moitzi
# License: MIT License
import pytest
import math
from ezdxf.math import (
    bulge_radius,
    bulge_center,
    arc_to_bulge,
    bulge_3_points,
    bulge_to_arc,
    bulge_from_radius_and_chord,
    bulge_from_arc_angle,
)


def test_bulge_radius():
    assert bulge_radius((0, 0), (1, 0), 1) == 0.5
    assert bulge_radius((0, 0), (1, 0), -1) == 0.5


def test_bulge_center():
    assert bulge_center((0, 0), (1, 0), 1).isclose((0.5, 0))
    assert bulge_center((0, 0), (1, 0), -1).isclose((0.5, 0))


def test_arc_to_bulge():
    start, end, bulge = arc_to_bulge(
        center=(0.5, 0), start_angle=math.pi, end_angle=0, radius=0.5
    )
    assert start.isclose((0.0, 0.0, 0.0))
    assert end.isclose((1.0, 0.0, 0.0))
    assert math.isclose(bulge, 1.0)


def test_bulge_3_points():
    assert math.isclose(
        bulge_3_points(start_point=(0, 0), end_point=(1, 0), point=(0.5, -0.5)),
        1.0,
    )


def test_bulge_to_arc():
    center, start_angle, end_angle, radius = bulge_to_arc(
        start_point=(0, 0), end_point=(1, 0), bulge=-1
    )
    assert center.isclose((0.5, 0.0, 0.0))
    assert math.isclose(start_angle, 0, abs_tol=1e-15)
    assert math.isclose(end_angle, math.pi)
    assert radius == 0.5


class TestBulgeFromRadiusAndChord:
    def test_semi_circle_bulge(self):
        assert math.isclose(bulge_from_radius_and_chord(5.0, 10), 1.0)

    def test_half_bulge(self):
        assert math.isclose(bulge_from_radius_and_chord(6.25, 10), 0.50)

    def test_radius_of_zero(self):
        assert bulge_from_radius_and_chord(0, 10) == 0.0

    def test_too_small_radius_for_chord(self):
        assert bulge_from_radius_and_chord(1, 10) == 0.0


@pytest.mark.parametrize("angle,bulge", [
    (180, 1.0),
    (-180, -1.0),
    (106.26020471, 0.5),
    (-106.26020471, -0.5),
    (56.14497387, 0.25),
    (-56.14497387, -0.25),
])
def test_bulge_from_arc_angle(angle, bulge):
    assert math.isclose(bulge_from_arc_angle(math.radians(angle)), bulge)