def unpack_segments(segments: Sequence[Segment],
context: Context) -> Union[Empty, Multisegment, Segment]:
return ((context.multisegment_cls(segments)
if len(segments) > 1
else segments[0])
if segments
else context.empty)
def _symmetric_subtract_segments_overlap(minuend: Segment,
subtrahend: Segment,
context: Context) -> Multisegment:
left_start, left_end, right_start, right_end = sorted([
minuend.start, minuend.end, subtrahend.start, subtrahend.end])
return context.multisegment_cls([context.segment_cls(left_start, left_end),
context.segment_cls(right_start,
right_end)])
def _unite_segments_cross(first: Segment,
second: Segment,
context: Context) -> Multisegment:
cross_point = context.segments_intersection(first, second)
segment_cls = context.segment_cls
return context.multisegment_cls([segment_cls(first.start, cross_point),
segment_cls(second.start, cross_point),
segment_cls(cross_point, first.end),
segment_cls(cross_point, second.end)])
def unite_segments(first: Segment,
second: Segment,
context: Context) -> Union_[Multisegment, Segment]:
relation = context.segments_relation(first, second)
if relation is Relation.DISJOINT:
return context.multisegment_cls([first, second])
elif relation is Relation.EQUAL or relation is Relation.COMPOSITE:
return first
elif relation is Relation.COMPONENT:
return second
else:
return (_unite_segments_touch
if relation is Relation.TOUCH
else (_unite_segments_cross
if relation is Relation.CROSS
else _unite_segments_overlap))(first, second, context)
def _subtract_segments_composite(minuend: Segment,
subtrahend: Segment,
context: Context
) -> Union_[Multisegment, Segment]:
left_start, left_end, right_start, right_end = sorted([
minuend.start, minuend.end, subtrahend.start, subtrahend.end])
return (context.segment_cls(right_start, right_end)
if left_start == subtrahend.start or left_start == subtrahend.end
else (((context.segment_cls(left_start, left_end)
if right_start == right_end
else
context.multisegment_cls([context.segment_cls(left_start,
left_end),
context.segment_cls(right_start,
right_end)]))
if (right_start == subtrahend.start
or right_start == subtrahend.end)
else context.segment_cls(left_start, left_end))
if left_end == subtrahend.start or left_end == subtrahend.end
else context.segment_cls(left_start, right_start)))
def symmetric_subtract_segments(first: Segment,
second: Segment,
context: Context
) -> Union_[Empty, Multisegment, Segment]:
relation = context.segments_relation(first, second)
if relation is Relation.DISJOINT:
return context.multisegment_cls([first, second])
elif relation is Relation.EQUAL:
return context.empty
else:
return (_unite_segments_touch(first, second, context)
if relation is Relation.TOUCH
else
(_unite_segments_cross(first, second, context)
if relation is Relation.CROSS
else
(_symmetric_subtract_segments_overlap(first, second, context)
if relation is Relation.OVERLAP
else (_subtract_segments_composite(first, second, context)
if relation is Relation.COMPOSITE
else _subtract_segments_composite(second, first,
context)))))
def _unite_segments_touch(first: Segment,
second: Segment,
context: Context) -> Union_[Multisegment, Segment]:
return (context.multisegment_cls([first, second])
if ((first.start != second.start
or (context.angle_orientation(first.start, first.end,
second.end)
is not Orientation.COLLINEAR))
and (first.start != second.end
or (context.angle_orientation(first.start, first.end,
second.start)
is not Orientation.COLLINEAR))
and (first.end != second.start
or (context.angle_orientation(first.end, first.start,
second.end)
is not Orientation.COLLINEAR))
and (first.end != second.end
or (context.angle_orientation(first.end, first.start,
second.start)
is not Orientation.COLLINEAR)))
else context.segment_cls(min(first.start, first.end,
second.start, second.end),
max(first.start, first.end,
second.start, second.end)))
def merge_segments(segments: Sequence[Segment], *,
context: Context) -> Multisegment:
return context.multisegment_cls(_merge_segments(segments, context=context))
def relate_segment(multiregion: Multiregion, segment: Segment,
context: Context) -> Relation:
return _relate_multisegment(multiregion,
context.multisegment_cls([segment]),
context.segment_box(segment), context)
def relate_segment(multipolygon: Multipolygon, segment: Segment,
context: Context) -> Relation:
return relate_multisegment(multipolygon,
context.multisegment_cls([segment]), context)