Added convex hull plugin

This commit is contained in:
Mario Voigt 2020-08-22 12:13:37 +02:00
parent cdb68f7fd9
commit 2b180a26f6
2 changed files with 132 additions and 0 deletions

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<?xml version="1.0" encoding="UTF-8"?>
<inkscape-extension xmlns="http://www.inkscape.org/namespace/inkscape/extension">
<name>Convex Hull</name>
<id>fablabchemnitz.de.convexhull</id>
<effect needs-live-preview="false">
<object-type>all</object-type>
<effects-menu>
<submenu name="Convex Hull"/>
</effects-menu>
</effect>
<script>
<command location="inx" interpreter="python">fablabchemnitz_convexhull.py</command>
</script>
</inkscape-extension>

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#!/usr/bin/env python3
import inkex
import sys
import numpy as n
from inkex.paths import CubicSuperPath
from inkex.transforms import Transform
from lxml import etree
link = lambda a,b: n.concatenate((a,b[1:]))
edge = lambda a,b: n.concatenate(([a],[b]))
'''
Convex Hull routine by Markus Kohler, found at https://gist.github.com/kohlerm/0337f7c64df42f21f96405b3f8e895f2, which itself is an implementation of:
https://github.com/flengyel/REST/blob/master/quickhull.py
Compute the convex hull of a set of points in the plane
Adapted from en.literateprograms.org/Quickhull_(Python,arrays)
Content available under MIT/X11 License at
http://en.literateprograms.org/LiteratePrograms:Copyrights
Copyright (c) 2008 the authors listed in the page history
(see http://en.literateprograms.org/index.php?title=Quickhull_(Python,_arrays)&action=history)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
IN THE SOFTWARE.
'''
def qhull(sample):
def dome(sample,base):
h, t = base
dists = n.dot(sample-h, n.dot(((0,-1),(1,0)),(t-h)))
outer = n.repeat(sample, dists>0, 0)
if len(outer):
pivot = sample[n.argmax(dists)]
return link(dome(outer, edge(h, pivot)),
dome(outer, edge(pivot, t)))
else:
return base
if len(sample) > 2:
axis = sample[:,0]
base = n.take(sample, [n.argmin(axis), n.argmax(axis)], 0)
return link(dome(sample, base),
dome(sample, base[::-1]))
else:
return sample
class ConvexHull(inkex.Effect):
def __init__(self):
inkex.Effect.__init__(self)
self.paths = {}
self.paths_clone_transform = {}
def joinWithNode (self, node, path, makeGroup=False, cloneTransform=None):
if (not path) or (len(path) == 0 ):
return
g = self.document.getroot()
# Now make a <path> element which contains the twist & is a child
# of the new <g> element
style = { 'stroke': '#000000', 'fill': 'none', 'stroke-width': '1' }
line_attribs = { 'style':str(inkex.Style(style)), 'd': path }
if (cloneTransform != None ) and (cloneTransform != '' ):
line_attribs['transform'] = cloneTransform
etree.SubElement(g, inkex.addNS('path', 'svg' ), line_attribs)
def effect(self):
global output_nodes, points
#Loop through all the selected items in Inkscape
for node in self.svg.selected.values():
#create numpy array of nodes
n_array = []
#Iterate through all the selected objects in Inkscape
for node in self.svg.selected.values():
#Check if the node is a path ("svg:path" node in XML )
#id = node.id
if node.tag == inkex.addNS('path','svg'):
# bake (or fuse) transform
node.apply_transform()
#turn into cubicsuperpath
d = node.get('d')
p = CubicSuperPath(d)
for subpath in p: # there may be several paths joined together (e.g. holes)
for csp in subpath: # groups of three to handle control points.
# just the points no control points (handles)
n_array.append(csp[1][0])
n_array.append(csp[1][1])
k = n.asarray(n_array)
length = int(len(k)/2)
c = k.reshape(length,2)
hull_pts = qhull(c)
pdata = ''
for vertex in hull_pts:
if pdata == '':
pdata = 'M%f,%f' % (vertex[0], vertex[1] )
else:
pdata += 'L %f,%f' % (vertex[0], vertex[1] )
pdata += ' Z'
path = 'polygon'
makeGroup = False
paths_clone_transform = None
self.joinWithNode(path, pdata, makeGroup, paths_clone_transform )
ConvexHull().run()