mightyscape-1.2/extensions/fablabchemnitz/chain_paths/chain_paths.py

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2022-09-20 18:29:28 +02:00
#!/usr/bin/env python3
#
# Inkscape extension making long continuous paths from shorter pieces.
# (C) 2015 juewei@fabmail.org
#
# code snippets visited to learn the extension 'effect' interface:
# - convert2dashes.py
# - http://github.com/jnweiger/inkscape-silhouette
# - http://github.com/jnweiger/inkscape-gears-dev
# - http://sourceforge.net/projects/inkcut/
# - http://code.google.com/p/inkscape2tikz/
# - http://code.google.com/p/eggbotcode/
#
# 2015-11-15 jw, V0.1 -- initial draught
# 2015-11-16 jw, V0.2 -- fixed endpoints after chaining.
# 2015-11-16 jw, V0.3 -- all possible chains connected. Yeah
# 2015-11-16 jw, V0.4 -- gui fully functional.
# 2015-11-26 jw, V0.5 -- HACK to resolve some self-reversing path segments.
# https://github.com/fablabnbg/inkscape-chain-paths/issues/1
# 2020-04-10 jw, V0.6 -- Close paths correctly. Self reversing path hack was too eager.
# Workaround for cubicsuperpath.parsePath/formatPath limitation.
# Started python3 compatibility.
# 2020-05-27 vi, V0.7 -- Upgrade to Inkscape 1.0. Write debug info to inkex debug dialog.
from __future__ import print_function
__version__ = '0.7' # Keep in sync with chain_paths.inx ca line 22
__author__ = 'Juergen Weigert <juergen@fabmail.org>'
__credits__ = ['Juergen Weigert', 'Veronika Irvine']
import sys
import math
import re
import inkex
from inkex.paths import CubicSuperPath, Path
from optparse import SUPPRESS_HELP
debug = False
class ChainPaths(inkex.EffectExtension):
def __init__(self):
inkex.Effect.__init__(self)
# For handling an SVG viewbox attribute, we will need to know the
# values of the document's <svg> width and height attributes as well
# as establishing a transform from the viewbox to the display.
self.chain_epsilon = 0.01
self.snap_ends = True
self.close_loops = True
self.segments_done = {}
self.min_missed_distance_sq = None
self.chained_count = 0
self.arg_parser.add_argument('-V', '--version', type=inkex.Boolean, default=False, help = 'Just print version number ("' + __version__ + '") and exit.')
self.arg_parser.add_argument('-s', '--snap_ends', type=inkex.Boolean, default=True, help='snap end-points together when connecting')
self.arg_parser.add_argument('-c', '--close_loops', type=inkex.Boolean, default=True, help='close loops (start/end of the same path)')
self.arg_parser.add_argument('-u', '--units', default="mm", help="measurement unit for epsilon")
self.arg_parser.add_argument('-e', '--chain_epsilon', type=float, default=0.01, help="Max. distance to connect [mm]")
def version(self):
return __version__
def author(self):
return __author__
def calc_unit_factor(self, units='mm'):
""" return the scale factor for all dimension conversions.
- The document units are always irrelevant as
everything in inkscape is expected to be in 90dpi pixel units
"""
dialog_units = self.svg.unittouu(str(1.0)+units)
self.unit_factor = 1.0 / dialog_units
return self.unit_factor
def reverse_segment(self, seg):
r = []
for s in reversed(seg):
# s has 3 elements: handle1, point, handle2
# Swap handles.
s.reverse()
r.append(s)
return r
def set_segment_done(self, id, n, msg=''):
if not id in self.segments_done:
self.segments_done[id] = {}
self.segments_done[id][n] = True
if debug: inkex.utils.debug("done "+str(id)+" "+str(n)+" "+msg)
def is_segment_done(self, id, n):
if not id in self.segments_done:
return False
if n in self.segments_done[id]:
return True
return False
def link_segments(self, seg1, seg2):
if self.snap_ends:
seg = seg1[:-1]
p1 = seg1[-1]
p2 = seg2[0]
# fuse p1 and p2 to create one new point:
# first handle from p1, point coordinates averaged, second handle from p2
seg.append([ [ p1[0][0] , p1[0][1] ],
[ (p1[1][0] + p2[1][0]) * .5, (p1[1][1] + p2[1][1]) * .5 ],
[ p2[2][0] , p2[2][1] ] ])
seg.extend(seg2[1:])
else:
seg = seg1[:]
seg.extend(seg2[:])
self.chained_count += 1
return seg
def near_ends(self, end1, end2):
""" requires self.eps_sq to be the square of the near distance """
dx = end1[0] - end2[0]
dy = end1[1] - end2[1]
d_sq = dx * dx + dy * dy
if d_sq > self.eps_sq:
if self.min_missed_distance_sq is None:
self.min_missed_distance_sq = d_sq
elif self.min_missed_distance_sq > d_sq:
self.min_missed_distance_sq = d_sq
return False
else:
return True
def effect(self):
if self.options.version:
print(__version__)
sys.exit(0)
self.calc_unit_factor(self.options.units)
if self.options.snap_ends is not None: self.snap_ends = self.options.snap_ends
if self.options.close_loops is not None: self.close_loops = self.options.close_loops
if self.options.chain_epsilon is not None: self.chain_epsilon = self.options.chain_epsilon
if self.chain_epsilon < 0.001: self.chain_epsilon = 0.001 # keep a minimum.
self.eps_sq = self.chain_epsilon * self.unit_factor * self.chain_epsilon * self.unit_factor
if not len(self.svg.selected.items()):
inkex.errormsg("Please select one or more objects.")
return
segments = []
for id, node in self.svg.selected.items():
if node.tag != inkex.addNS('path', 'svg'):
inkex.errormsg("Object " + id + " is not a path. Try\n - Path->Object to Path\n - Object->Ungroup")
return
if debug: inkex.utils.debug("id=" + str(id) + ", tag=" + str(node.tag))
path_d = CubicSuperPath(Path(node.get('d')))
sub_idx = -1
for sub in path_d:
sub_idx += 1
# sub = [[[200.0, 300.0], [200.0, 300.0], [175.0, 290.0]], [[175.0, 265.0], [220.37694, 256.99876], [175.0, 240.0]], [[175.0, 215.0], [200.0, 200.0], [200.0, 200.0]]]
# this is a path of three points. All the bezier handles are included. the Structure is:
# [[handle0_OUT, point0, handle0_1], [handle1_0, point1, handle1_2], [handle2_1, point2, handle2_OUT]]
# the _OUT handles at the end of the path are ignored. The data structure has them identical to their points.
#
if debug: inkex.utils.debug(" sub=" + str(sub))
end1 = [sub[ 0][1][0], sub[ 0][1][1]]
end2 = [sub[-1][1][0], sub[-1][1][1]]
# Remove trivial self revesal when building candidate segments list.
if ((len(sub) == 3) and self.near_ends(end1, end2)):
if debug: inkex.utils.debug("dropping segment from self-reversing path, length:"+str(len(sub)))
sub.pop()
end2 = [sub[-1][1][0], sub[-1][1][1]]
segments.append({'id': id, 'n': sub_idx, 'end1': end1, 'end2':end2, 'seg': sub})
if node.get(inkex.addNS('type', 'sodipodi')):
del node.attrib[inkex.addNS('type', 'sodipodi')]
if debug: inkex.utils.debug("-------- seen: ")
for s in segments:
if debug: inkex.utils.debug(str(s['id'])+", "+str(s['n'])+", "+str(s['end1'])+", "+str(s['end2']))
# chain the segments
obsoleted = 0
remaining = 0
for id, node in self.svg.selected.items():
path_d = CubicSuperPath(Path(node.get('d')))
# ATTENTION: for parsePath() it is the same, if first and last point coincide, or if the path is really closed.
2023-12-10 16:19:34 +01:00
path_closed = True if re.search(r'z\s*$', node.get('d')) else False
2022-09-20 18:29:28 +02:00
new = []
cur_idx = -1
for chain in path_d:
cur_idx += 1
if not self.is_segment_done(id, cur_idx):
# quadratic algorithm: we check both ends of the current segment.
# If one of them is near another known end from the segments list, we
# chain this segment to the current segment and remove it from the
# list,
# end1-end1 or end2-end2: The new segment is reversed.
# end1-end2: The new segment is prepended to the current segment.
# end2-end1: The new segment is appended to the current segment.
self.set_segment_done(id, cur_idx, "output") # do not cross with ourselves.
end1 = [chain[ 0][1][0], chain[ 0][1][1]]
end2 = [chain[-1][1][0], chain[-1][1][1]]
# Remove trivial self revesal when doing the actual chain operation.
if ((len(chain) == 3) and self.near_ends(end1, end2)):
chain.pop()
end2 = [chain[-1][1][0], chain[-1][1][1]]
segments_idx = 0
while segments_idx < len(segments):
seg = segments[segments_idx]
if self.is_segment_done(seg['id'], seg['n']):
segments_idx += 1
continue
if (self.near_ends(end1, seg['end1']) or
self.near_ends(end2, seg['end2'])):
seg['seg'] = self.reverse_segment(seg['seg'])
seg['end1'], seg['end2'] = seg['end2'], seg['end1']
if debug: inkex.utils.debug("reversed seg " + str(seg['id']) + ", "+str(seg['n']))
if self.near_ends(end1, seg['end2']):
# prepend seg to chain
self.set_segment_done(seg['id'], seg['n'], 'prepended to ' + str(id) + ' ' + str(cur_idx))
chain = self.link_segments(seg['seg'], chain)
end1 = [chain[0][1][0], chain[0][1][1]]
segments_idx = 0 # this chain changed. re-visit all candidate
continue
if self.near_ends(end2, seg['end1']):
# append seg to chain
self.set_segment_done(seg['id'], seg['n'], 'appended to ' + str(id) + ' ' + str(cur_idx))
chain = self.link_segments(chain, seg['seg'])
end2 = [chain[-1][1][0], chain[-1][1][1]]
segments_idx = 0 # this chain changed. re-visit all candidate
continue
segments_idx += 1
# Now all joinable segments are joined.
# Finally, we can check, if the resulting path is a closed path:
# Closing a path here, isolates it from the rest.
# But as we prefer to make the chain as long as possible, we close late.
if self.near_ends(end1, end2) and not path_closed and self.close_loops:
if debug: inkex.utils.debug("closing closeable loop " +str(id))
if self.snap_ends:
# move first point to mid position
x1n = (chain[0][1][0] + chain[-1][1][0]) * 0.5
y1n = (chain[0][1][1] + chain[-1][1][1]) * 0.5
chain[0][1][0], chain[0][1][1] = x1n, y1n
# merge handle of the last point to the handle of the first point
dx0e = chain[-1][0][0] - chain[-1][1][0]
dy0e = chain[-1][0][1] - chain[-1][1][1]
if debug: inkex.utils.debug("handle diff: "+ str(dx0e) + str(dy0e))
# FIXME: this does not work. cubicsuperpath.formatPath() ignores this handle.
chain[0][0][0], chain[0][0][1] = x1n+dx0e, y1n+dy0e
# drop last point
chain.pop()
end2 = [chain[-1][1][0], chain[-1][1][1]]
path_closed = True
self.chained_count +=1
new.append(chain)
if not len(new):
# node.clear()
if node.getparent() is not None:
node.delete()
obsoleted += 1
if debug: inkex.utils.debug("Path node obsoleted: " +str(id))
else:
remaining += 1
# BUG: All previously closed loops, are open, after we convert them back with cubicsuperpath.formatPath()
p_fmt = str(Path(CubicSuperPath(new).to_path().to_arrays()))
if path_closed: p_fmt += " z"
if debug: inkex.utils.debug("new path: "+str(p_fmt))
node.set('d', p_fmt)
# statistics:
if debug: inkex.utils.debug("Path nodes obsoleted: "+str(obsoleted) + "\nPath nodes remaining:"+str(remaining))
if self.min_missed_distance_sq is not None:
if debug: inkex.utils.debug("min_missed_distance: "+str(math.sqrt(float(self.min_missed_distance_sq))/self.unit_factor)+'>'+str(self.chain_epsilon)+str(self.options.units))
if debug: inkex.utils.debug("Successful link operations: "+str(self.chained_count))
if __name__ == '__main__':
ChainPaths().run()