def relate_multisegment(goal: Multisegment, test: Multisegment,
context: Context) -> Relation:
goal_bounding_box = context.segments_box(goal.segments)
test_bounding_box = context.segments_box(test.segments)
if box.disjoint_with(goal_bounding_box, test_bounding_box):
return Relation.DISJOINT
events_queue = LinearEventsQueue(context)
events_queue.register(to_segments_endpoints(goal), from_test=False)
events_queue.register(to_segments_endpoints(test), from_test=True)
return process_open_linear_queue(
events_queue, min(goal_bounding_box.max_x, test_bounding_box.max_x))
def relate_multisegment(contour: Contour, multisegment: Multisegment,
context: Context) -> Relation:
contour_bounding_box = context.contour_box(contour)
multisegment_bounding_box = context.segments_box(multisegment.segments)
if box.disjoint_with(contour_bounding_box, multisegment_bounding_box):
return Relation.DISJOINT
events_queue = LinearEventsQueue(context)
events_queue.register(to_edges_endpoints(contour), from_test=False)
events_queue.register(to_segments_endpoints(multisegment), from_test=True)
return process_open_linear_queue(
events_queue,
min(contour_bounding_box.max_x, multisegment_bounding_box.max_x))
def relate_multisegment(polygon: Polygon, multisegment: Multisegment,
context: Context) -> Relation:
polygon_bounding_box = context.polygon_box(polygon)
multisegment_bounding_box = context.segments_box(multisegment.segments)
if box.disjoint_with(polygon_bounding_box, multisegment_bounding_box):
return Relation.DISJOINT
events_queue = CompoundEventsQueue(context)
events_queue.register(to_oriented_edges_endpoints(polygon, context),
from_test=False)
events_queue.register(to_segments_endpoints(multisegment), from_test=True)
return process_linear_compound_queue(
events_queue,
min(multisegment_bounding_box.max_x, polygon_bounding_box.max_x))
def relate_multisegment(multipolygon: Multipolygon, multisegment: Multisegment,
context: Context) -> Relation:
multisegment_bounding_box = context.segments_box(multisegment.segments)
disjoint, multipolygon_max_x, events_queue = True, None, None
for polygon in multipolygon.polygons:
polygon_bounding_box = context.polygon_box(polygon)
if not box.disjoint_with(polygon_bounding_box,
multisegment_bounding_box):
if disjoint:
disjoint = False
multipolygon_max_x = polygon_bounding_box.max_x
events_queue = CompoundEventsQueue(context)
events_queue.register(to_segments_endpoints(multisegment),
from_test=True)
else:
multipolygon_max_x = max(multipolygon_max_x,
polygon_bounding_box.max_x)
events_queue.register(polygon_to_oriented_segments(
polygon, context),
from_test=False)
return (Relation.DISJOINT if disjoint else process_linear_compound_queue(
events_queue, min(multisegment_bounding_box.max_x,
multipolygon_max_x)))
def relate_multisegment(multiregion: Multiregion, multisegment: Multisegment,
context: Context) -> Relation:
return _relate_multisegment(multiregion, multisegment,
context.segments_box(multisegment.segments),
context)
def from_multisegment(cls,
multisegment: Multisegment,
*,
shuffler: Shuffler = random.shuffle,
context: Context) -> 'Graph':
"""
Constructs trapezoidal decomposition graph of given multisegment.
Based on incremental randomized algorithm by R. Seidel.
Time complexity:
``O(segments_count * log segments_count)`` expected,
``O(segments_count ** 2)`` worst
Memory complexity:
``O(segments_count)``
where ``segments_count = len(multisegment.segments)``
Reference:
https://doi.org/10.1016%2F0925-7721%2891%2990012-4
https://www.cs.princeton.edu/courses/archive/fall05/cos528/handouts/A%20Simple%20and%20fast.pdf
:param multisegment: target multisegment.
:param shuffler:
function which mutates sequence by shuffling its elements,
required for randomization.
:param context: geometric context.
:returns: trapezoidal decomposition graph of the multisegment.
>>> from ground.base import get_context
>>> context = get_context()
>>> Multisegment, Point, Segment = (context.multisegment_cls,
... context.point_cls,
... context.segment_cls)
>>> graph = Graph.from_multisegment(
... Multisegment([Segment(Point(0, 0), Point(1, 0)),
... Segment(Point(0, 0), Point(0, 1))]),
... context=context)
>>> Point(1, 0) in graph
True
>>> Point(0, 1) in graph
True
>>> Point(1, 1) in graph
False
>>> graph.locate(Point(1, 0)) is Location.BOUNDARY
True
>>> graph.locate(Point(0, 1)) is Location.BOUNDARY
True
>>> graph.locate(Point(1, 1)) is Location.EXTERIOR
True
"""
edges = [
Edge.from_endpoints(segment.start, segment.end, False, context)
if segment.start < segment.end else Edge.from_endpoints(
segment.end, segment.start, False, context)
for segment in multisegment.segments
]
shuffler(edges)
result = cls(
box_to_node(context.segments_box(multisegment.segments), context))
for edge in edges:
add_edge(result, edge)
return result