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replacing shapely parallel_offset by buffer

pull/1548/head
Andreas 2022-03-21 20:39:06 +01:00 zatwierdzone przez Kaalleen
rodzic 6916a33716
commit f75c812aba
1 zmienionych plików z 90 dodań i 75 usunięć
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165
lib/stitches/tangential_fill_stitch_line_creator.py
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@ -2,7 +2,7 @@ from shapely.geometry.polygon import LinearRing, LineString
from shapely.geometry import Polygon, MultiLineString
from shapely.ops import polygonize
from shapely.geometry import MultiPolygon
from anytree import AnyNode, PreOrderIter, LevelOrderGroupIter
from anytree import AnyNode, PreOrderIter, LevelOrderGroupIter, RenderTree
from shapely.geometry.polygon import orient
from depq import DEPQ
from enum import IntEnum
@ -10,79 +10,94 @@ from ..stitches import tangential_fill_stitch_pattern_creator
from ..stitches import constants
def offset_linear_ring(ring, offset, side, resolution, join_style, mitre_limit):
"""
Solves following problem: When shapely offsets a LinearRing the
start/end point might be handled wrongly since they
are only treated as LineString.
(See e.g. https://i.stack.imgur.com/vVh56.png as a problematic example)
This method checks first whether the start/end point form a problematic
edge with respect to the offset side. If it is not a problematic
edge we can use the normal offset_routine. Otherwise we need to
perform two offsets:
-offset the ring
-offset the start/end point + its two neighbors left and right
Finally both offsets are merged together to get the correct
offset of a LinearRing
"""
def offset_linear_ring(ring, offset, resolution, join_style, mitre_limit):
result = Polygon(ring).buffer(offset, resolution, cap_style=2, join_style=join_style, mitre_limit=mitre_limit, single_sided=True)
coords = ring.coords[:]
# check whether edge at index 0 is concave or convex. Only for
# concave edges we need to spend additional effort
dx_seg1 = dy_seg1 = 0
if coords[0] != coords[-1]:
dx_seg1 = coords[0][0] - coords[-1][0]
dy_seg1 = coords[0][1] - coords[-1][1]
if result.geom_type == 'Polygon':
return result.exterior
else:
dx_seg1 = coords[0][0] - coords[-2][0]
dy_seg1 = coords[0][1] - coords[-2][1]
dx_seg2 = coords[1][0] - coords[0][0]
dy_seg2 = coords[1][1] - coords[0][1]
# use cross product:
crossvalue = dx_seg1 * dy_seg2 - dy_seg1 * dx_seg2
sidesign = 1
if side == "left":
sidesign = -1
# We do not need to take care of the joint n-0 since we
# offset along a concave edge:
if sidesign * offset * crossvalue <= 0:
return ring.parallel_offset(offset, side, resolution, join_style, mitre_limit)
# We offset along a convex edge so we offset the joint n-0 separately:
if coords[0] != coords[-1]:
coords.append(coords[0])
offset_ring1 = ring.parallel_offset(
offset, side, resolution, join_style, mitre_limit
)
offset_ring2 = LineString((coords[-2], coords[0], coords[1])).parallel_offset(
offset, side, resolution, join_style, mitre_limit
)
# Next we need to merge the results:
if offset_ring1.geom_type == "LineString":
return LinearRing(offset_ring2.coords[:] + offset_ring1.coords[1:-1])
else:
# We have more than one resulting LineString for offset of
# the geometry (ring) = offset_ring1.
# Hence we need to find the LineString which belongs to the
# offset of element 0 in coords =offset_ring2
# in order to add offset_ring2 geometry to it:
result_list = []
thresh = constants.offset_factor_for_adjacent_geometry * abs(offset)
for offsets in offset_ring1:
if (
abs(offsets.coords[0][0] - coords[0][0]) < thresh
and abs(offsets.coords[0][1] - coords[0][1]) < thresh
):
result_list.append(
LinearRing(offset_ring2.coords[:] + offsets.coords[1:-1])
)
else:
result_list.append(LinearRing(offsets))
for poly in result:
result_list.append(poly.exterior)
return MultiLineString(result_list)
# """
# Solves following problem: When shapely offsets a LinearRing the
# start/end point might be handled wrongly since they
# are only treated as LineString.
# (See e.g. https://i.stack.imgur.com/vVh56.png as a problematic example)
# This method checks first whether the start/end point form a problematic
# edge with respect to the offset side. If it is not a problematic
# edge we can use the normal offset_routine. Otherwise we need to
# perform two offsets:
# -offset the ring
# -offset the start/end point + its two neighbors left and right
# Finally both offsets are merged together to get the correct
# offset of a LinearRing
# """
#PROBLEM: Did not work in rare cases since it expects the point order be maintained after offsetting the curve
#(e.g. the first point in the offsetted curve shall belong to the first point in the original curve). However, this
#assumption seems to be not always true that is why this code was replaced by the buffer routine.
# coords = ring.coords[:]
# # check whether edge at index 0 is concave or convex. Only for
# # concave edges we need to spend additional effort
# dx_seg1 = dy_seg1 = 0
# if coords[0] != coords[-1]:
# dx_seg1 = coords[0][0] - coords[-1][0]
# dy_seg1 = coords[0][1] - coords[-1][1]
# else:
# dx_seg1 = coords[0][0] - coords[-2][0]
# dy_seg1 = coords[0][1] - coords[-2][1]
# dx_seg2 = coords[1][0] - coords[0][0]
# dy_seg2 = coords[1][1] - coords[0][1]
# # use cross product:
# crossvalue = dx_seg1 * dy_seg2 - dy_seg1 * dx_seg2
# sidesign = 1
# if side == "left":
# sidesign = -1
# # We do not need to take care of the joint n-0 since we
# # offset along a concave edge:
# if sidesign * offset * crossvalue <= 0:
# return ring.parallel_offset(offset, side, resolution, join_style, mitre_limit)
# # We offset along a convex edge so we offset the joint n-0 separately:
# if coords[0] != coords[-1]:
# coords.append(coords[0])
# offset_ring1 = ring.parallel_offset(
# offset, side, resolution, join_style, mitre_limit
# )
# offset_ring2 = LineString((coords[-2], coords[0], coords[1])).parallel_offset(
# offset, side, resolution, join_style, mitre_limit
# )
# # Next we need to merge the results:
# if offset_ring1.geom_type == "LineString":
# return LinearRing(offset_ring2.coords[:] + offset_ring1.coords[1:-1])
# else:
# # We have more than one resulting LineString for offset of
# # the geometry (ring) = offset_ring1.
# # Hence we need to find the LineString which belongs to the
# # offset of element 0 in coords =offset_ring2
# # in order to add offset_ring2 geometry to it:
# result_list = []
# thresh = constants.offset_factor_for_adjacent_geometry * abs(offset)
# for offsets in offset_ring1:
# if (
# abs(offsets.coords[0][0] - coords[0][0]) < thresh
# and abs(offsets.coords[0][1] - coords[0][1]) < thresh
# ):
# result_list.append(
# LinearRing(offset_ring2.coords[:] + offsets.coords[1:-1])
# )
# else:
# result_list.append(LinearRing(offsets))
# return MultiLineString(result_list)
def take_only_valid_linear_rings(rings):
"""
Removes all geometries which do not form a "valid" LinearRing
@ -99,13 +114,15 @@ def take_only_valid_linear_rings(rings):
return LinearRing(new_list[0])
else:
return MultiLineString(new_list)
else:
elif rings.geom_type == "LineString" or rings.geom_type == "LinearRing":
if len(rings.coords) <= 2:
return LinearRing()
elif len(rings.coords) == 3 and rings.coords[0] == rings.coords[-1]:
return LinearRing()
else:
return rings
else:
return LinearRing()
def make_tree_uniform_ccw(root):
@ -223,7 +240,6 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
outer = offset_linear_ring(
current_poly.val,
offset,
"left",
resolution=5,
join_style=join_style,
mitre_limit=10,
@ -234,8 +250,7 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
for j in range(len(current_holes)):
inner = offset_linear_ring(
current_holes[j].val,
offset,
"left",
-offset, #take negative offset for holes
resolution=5,
join_style=join_style,
mitre_limit=10,
@ -246,12 +261,12 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
poly_inners.append(Polygon(inner))
if not outer.is_empty:
if len(poly_inners) == 0:
if outer.geom_type == "LineString":
if outer.geom_type == "LineString" or outer.geom_type == "LinearRing":
result = Polygon(outer)
else:
result = MultiPolygon(polygonize(outer))
else:
if outer.geom_type == "LineString":
if outer.geom_type == "LineString" or outer.geom_type == "LinearRing":
result = Polygon(outer).difference(
MultiPolygon(poly_inners))
else:
@ -312,7 +327,7 @@ def offset_poly(poly, offset, join_style, stitch_distance, min_stitch_distance,
if previous_hole.parent is None:
previous_hole.parent = current_poly
#print(RenderTree(root))
make_tree_uniform_ccw(root)
if strategy == StitchingStrategy.CLOSEST_POINT: