def pred_poly_by_line(self,
polygon: Polygon,
splitter: Segment) -> PolygonsSet:
pred_poly_by_edges = self._pred_poly_by_edges(polygon)
vertices_in_interval = cut(polygon.border,
splitter.start,
splitter.end)
edges_in_interval = Multisegment(*map(Segment,
vertices_in_interval[:-1],
vertices_in_interval[1:]))
return PolygonsSet({part
for edge, pred_poly in pred_poly_by_edges.items()
for part in pred_poly
if isinstance(edge & edges_in_interval, Segment)})
def plr(self,
polygon: Polygon,
splitter: Segment) -> RootedPolygons:
"""
Portion of the current polygon to the right of the splitter
plus all immediate ancestors accessible through the polygon
edges that lie on the right of the splitter
"""
vertices_in_interval = cut(polygon.border,
splitter.start,
splitter.end)
if len(vertices_in_interval) < 3:
current_polygon_part = EMPTY
else:
contour = Contour(shrink_collinear_vertices(
Contour(vertices_in_interval)))
current_polygon_part = Polygon(contour)
pred_poly_by_line = self.pred_poly_by_line(polygon, splitter=splitter)
return RootedPolygons(root=current_polygon_part,
predecessors=pred_poly_by_line)
def test_both_directions(
contour_and_points: Tuple[Contour, Point, Point]) -> None:
contour, start, end = contour_and_points
right_vertices = cut(contour, start, end)
left_vertices = cut(contour, end, start)
assert {*right_vertices, *left_vertices} == {*contour.vertices, start, end}
def test_duplicates(contour_and_points: Tuple[Contour, Point, Point]) -> None:
contour, start, end = contour_and_points
vertices = cut(contour, start, end)
assert len(set(vertices)) == len(vertices)
def test_segments(contour_and_points: Tuple[Contour, Point, Point]) -> None:
contour, start, end = contour_and_points
vertices = cut(contour, start, end)
segments = map(Segment, vertices[:-1], vertices[1:])
assert all(segment < contour for segment in segments)
def test_vertices(contour_and_points: Tuple[Contour, Point, Point]) -> None:
contour, start, end = contour_and_points
assert all(point in contour for point in cut(contour, start, end))