svgpathtools/examples/determine-if-svg-path-is-contained-in-other-path-example.py

"""
An example of how to determine if an svg path is contained in another 
svg path in Python.

Note: for discontinuous paths you can use the svgpathtools 
Path.continuous_subpaths() method to split a paths into a list of its 
continuous subpaths.
"""

from svgpathtools import Path, Line


def path1_is_contained_in_path2(path1, path2):
    assert path2.isclosed()  # This question isn't well-defined otherwise
    if path2.intersect(path1):
        return False

    # find a point that's definitely outside path2
    xmin, xmax, ymin, ymax = path2.bbox()
    b = (xmin + 1) + 1j*(ymax + 1)

    a = path1.start  # pick an arbitrary point in path1
    ab_line = Path(Line(a, b))
    number_of_intersections = len(ab_line.intersect(path2))
    if number_of_intersections % 2:  # if number of intersections is odd
        return True
    else:
        return False


# Test examples
closed_path = Path(Line(0,5), Line(5,5+5j), Line(5+5j, 0))
path_that_is_contained = Path(Line(1+1j, 2+2j))
print(path1_is_contained_in_path2(path_that_is_contained, closed_path))

path_thats_not_contained = Path(Line(10+10j, 20+20j))
print(path1_is_contained_in_path2(path_thats_not_contained, closed_path))

path_that_intersects = Path(Line(2+1j, 10+10j))
print(path1_is_contained_in_path2(path_that_intersects, closed_path))