DemoLineclip.py

#!/usr/bin/env python
from pylineclip import cohensutherland
from pytest import approx
"""
make box with corners LL/UR (1,3) (4,5)
and line segment with ends (0,0) (4,6)
"""


def main():
    # %% LOWER to UPPER test
    x1, y1, x2, y2 = cohensutherland(1, 5, 4, 3, 0, 0, 4, 6)

    assert [x1, y1, x2, y2] == approx([2, 3, 3.3333333333333, 5])
    # %% no intersection test
    x1, y1, x2, y2 = cohensutherland(1, 5, 4, 3, 0, 0.1, 0, 0.1)

    assert x1 is None and y1 is None and x2 is None and y2 is None
    # %% left to right test
    x1, y1, x2, y2 = cohensutherland(1, 5, 4, 3, 0, 4, 5, 4)
    assert [x1, y1, x2, y2] == [1, 4, 4, 4]


if __name__ == '__main__':
    main()