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from shapely.geometry import LineString, MultiPolygon, Polygon
from shapely.geometry.base import CAP_STYLE, JOIN_STYLE
from shapely.ops import triangulate
[docs]def buffered_shape(shape, width: float = 1.0) -> Polygon:
"""Generates a shape with a buffer of `width` around the original shape."""
ls = LineString(shape).buffer(
width / 2,
1,
cap_style=CAP_STYLE.flat,
join_style=JOIN_STYLE.round,
mitre_limit=5.0,
)
if isinstance(ls, MultiPolygon):
# Sometimes it oddly outputs a MultiPolygon and then we need to turn it into a convex hull
ls = ls.convex_hull
elif not isinstance(ls, Polygon):
raise RuntimeError("Shapely `object.buffer` behavior may have changed.")
return ls
[docs]def triangulate_polygon(polygon: Polygon):
"""Attempts to convert a polygon into triangles."""
# XXX: shapely.ops.triangulate current creates a convex fill of triangles.
return [
tri_face
for tri_face in triangulate(polygon)
if tri_face.centroid.within(polygon)
]