Inkscape

Hello,
Thank you for providing this extension for Inkscape users!

This is just to let you know that most 3rd party Inkscape extensions, like this one, probably will not work with the upcoming new Inkscape version, the long-awaited version 1.0.

Here is the info you need to update this extension, so that it will work with 1.0 and future versions.
https://wiki.inkscape.org/wiki/index.php?title=Updating_your_Extension_for_1.0

If you have further questions, you can contact Inkscape developers via mailing lists (https://lists.inkscape.org/postorius/lists/?all-lists), forum (https://inkscape.org/forums/extensions/), or the chatroom (https://chat.inkscape.org/channel/team_devel)

If you have already updated it, please disregard this message.

All best,
brynn

And updated python code:

#!/usr/bin/env python3

# These two lines are only needed if you don't put the script directly into
# the installation directory
import math
import inkex
from simplestyle import *
import random
from lxml import etree

class blobsEffect(inkex.Effect):
"""
Creates a random blob from a convex hull over n points.
The expected degree of the polygon is sqrt(n). The corners
are blunted by the blunt parameter. 0 means sharp. 1 will
result in loopy splines.
"""
def __init__(self):
inkex.Effect.__init__(self)
self.arg_parser.add_argument("--pgsizep", type=inkex.Boolean, default=True, help="Default rectangle to page size?")
self.arg_parser.add_argument('--num', type = int, default = 25, help = 'Number of random points to start with')
self.arg_parser.add_argument('--blunt', type = float, default = 0.3, help = 'Bluntness of corners. Should be < 1')
self.arg_parser.add_argument('--cave', type = float, default = 0.0, help = 'Concavity. Less blobby and more splatty')
self.arg_parser.add_argument('--rx', type = int, default = 1000, help = 'Size of work area x')
self.arg_parser.add_argument('--ry', type = int, default = 1000, help = 'Size of work area y')
self.arg_parser.add_argument('--sz', type = float, default = 50., help = 'Size of a blob')
self.arg_parser.add_argument('--nb', type = int, default = 10, help = 'Total number of blobs')
self.arg_parser.add_argument("--Nmain", default='top', help="Active tab.")

def effect(self):
global cave
if self.options.pgsizep:
svg = self.document.getroot()
rx = self.svg.unittouu(svg.get('width'))
ry = self.svg.unittouu(svg.attrib['height'])
else:
rx = self.options.rx
ry = self.options.ry
blunt = self.options.blunt
cave = self.options.cave
sz = self.options.sz
nb = self.options.nb
num = self.options.num

# Get access to main SVG document element and get its dimensions.
svg = self.document.getroot()

# Create a new layer.
layer = etree.SubElement(svg, 'g')
layer.set(inkex.addNS('label', 'inkscape'), 'Blob Layer')
layer.set(inkex.addNS('groupmode', 'inkscape'), 'layer')

ctrs = [(random.randrange(rx) , random.randrange(ry))
for i in range(nb) ]
for ctr in ctrs :
points = [(random.gauss(ctr[0], sz) , random.gauss(ctr[1], sz))
for i in range(num) ]

px = hull(points)
pts = [points[px[i]] for i in range(len(px))]

# Create path element
path = etree.Element(inkex.addNS('path','svg'))
path.set('style', str(inkex.Style({'fill':'#000000'})))
pathstring = 'M ' + str(pts[0][0]) + ' ' + str(pts[0][1]) + ' '

for j in range(len(pts)):
k = (j+1) % len(pts)
kk = (j+2) % len(pts)
if j==0 :
(lasth, h1) = sHandles(pts[-1], pts[0], pts[1], blunt)
(h2, hnext) = sHandles(pts[j], pts[k], pts[kk], blunt)
pathstring += "C %f %f %f %f %f %f " % (h1[0], h1[1],
h2[0], h2[1],
pts[k][0], pts[k][1])
h1 = hnext

pathstring += 'Z'
path.set('d', pathstring)
layer.append(path)

def sHandles(pre, pt, post, blunt):
'''I'm proud of this cute little construction for the
spline handles. No doubt someone has thought of it before
but, if not, its name is ACHC Andrew's Cute Handle
Construction. Note: no trig function calls.'''
try :
slope = (post[1] - pt[1]) / (post[0] - pt[0])
except ZeroDivisionError :
slope = math.copysign(1E30 , post[1] - pt[1])
lenpre = distance(pre, pt)
lenpost = distance(pt, post)
lenr = lenpre**2 / lenpost
locx = math.copysign(lenr / math.sqrt(1. + slope**2) , post[0] - pt[0])
mark = (pre[0] - locx , pre[1] - locx*slope)
try :
markslope = (pt[1] - mark[1]) / (pt[0] - mark[0])
except ZeroDivisionError :
markslope = math.copysign(1E30 , pt[1] - mark[1])
prex = math.copysign(lenpre / math.sqrt(1. + markslope**2) ,
pt[0] - mark[0])
hpre = (pt[0] - prex*blunt , pt[1] - prex*markslope*blunt)
postx = prex*lenpost/lenpre
hpost = (pt[0] + postx*blunt , pt[1] + postx*markslope*blunt)
return (hpre, hpost)

"""Blunt=0.3 makes pleasingly round, mostly convex blobs. 0.4 makes them more
concave. 0.6 - 1.0 they're getting more and more pointy. 2.0 - 10. and they
grow appendages like hot-air balloons. 0.1 makes the corners pretty sharp.
0.0 and it's down to the convex hulls that are the basis of the blobs, that
is, polygons"""

def distance(a, b) :
return math.sqrt((a[0] - b[0])**2 + (a[1] - b[1])**2 )

def hull(arg):
"""Convex hull by Graham scan."""
xarr, yarr = zip(* arg)
ymin = min(yarr)
ind = findall(yarr, lambda y: y == ymin)
if len(ind) > 1 :
xshort = [xarr[j] for j in ind]
xmin = min(xshort)
j = ind[xshort.index(xmin)]
ind = j
else :
ind = ind[0]
all = list(range(len(xarr)))
del all[ind]
all.sort(key=lambda i : (xarr[i] - xarr[ind]) /
math.sqrt((xarr[i] - xarr[ind])**2 + (yarr[i] - yarr[ind])**2),
reverse=True)
if len(all) < 3 :
all.insert(0, ind)
return all
ans = [ind]
for i in all :
if len(ans) == 1 :
ans.append(i)
else :
while rightTurn(ans[-2], ans[-1], i, arg) :
ans.pop()
ans.append(i)

return ans

def rightTurn(j, k, l, arg) :
'''Cross product: Ax*By - Ay*Bx = Cz '''
ax = (arg[k][0] - arg[j][0])
by = (arg[l][1] - arg[k][1])
ay = (arg[k][1] - arg[j][1])
bx = (arg[l][0] - arg[k][0])
p = ax*by - ay*bx
dot = ax*bx + ay*by
cos = dot / math.sqrt((ax**2 + ay**2) * (bx**2 + by**2))
crt = 1 - cave*2

if p <= 0 :
return cos < crt #We forgive right turns based on /cave/
else :
return False

def findall(a, f):
r = []
for x, j in zip(a, range(len(a))) :
if f(x) :
r.append(j)
return r

# Create effect instance and apply it.
blobsEffect().run()