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

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#!/usr/bin/env python3
"""
Copyright (C) 2017 Panagiotis Loukas
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 WAphiANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WAphiANTIES 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.
Version 0.2
This script was written by Panagiotis Loukas to make spiral easy.
It simply,
Have fun :)
PS.
Written on Arch.
"""
import inkex
from lxml import etree
from math import cos, sin, pi, log, sqrt
class Archimedes(inkex.EffectExtension):
def add_arguments(self, pars):
pars.add_argument('--tab')
pars.add_argument('--r', type = int, default = '50')
pars.add_argument('--a', type = float, default = '3')
pars.add_argument('--step', type = int, default = '50')
pars.add_argument('--trl', default = '1')
pars.add_argument('--turns', type = float, default = '5')
pars.add_argument('--length', type = float, default = '500')
def effect(self):
th = pi / 3
a = self.options.a
r = self.options.r
length = self.options.length
if length > 0:
turns = self.angle(a, r, length, th) / (2 * pi)
else:
turns = self.options.turns
if self.options.trl == '1':
step = -self.options.step
else:
step = self.options.step
layer = etree.SubElement(self.document.getroot(),'g')
path = etree.Element(inkex.addNS('path','svg'))
path.set('d', self.built(r, step, a, turns))
path.set('style',"fill:none;stroke:#000000;stroke-width:1px;stroke-opacity:1")
layer.append(path)
def built(self, r0, st = 4, a = 4, k = 1, th = 0):
step = 2 * pi / st
r = r0
s = "M " + str(r * cos(th)) + ", " + str(-r * sin(th))
for i in range(0, int(k * (abs(st)))):
prin = th + i * step
meta = th + (i + 1) * step
rp = r0 + abs(a * prin)# instead we put the absolute value the spiral will drift inwards
rm = r0 + abs(a * meta)# at the absolute price closes outwards
s += "a " + str(rm) + "," + str(rm) + " 0 0," + self.options.trl + " " + str(-rp * cos(prin) + rm * cos(meta)) + "," + str(rp * sin(prin) -rm * sin(meta))
return s
# see https://mathepedia.de/Archimedische_Spirale.html for formula of total arc length
def spirallength(self, a, r0, th):
phi = (r0 / a) + th
phi_sqrt = sqrt(phi ** 2 + 1)
return (a / 2) * (phi * phi_sqrt + log(phi + phi_sqrt))
def ds(self, a, r0, th):
return self.spirallength(a, r0, th) - self.spirallength(a, r0, 0)
def angle(self, a, r0, length, th):
i = 0.0
while (True):
ls=self.ds(a, r0, i)
if length - ls > 100:
i += 0.01
elif length - ls > 10: i += 0.001
elif length - ls > 1: i += 0.0001
elif length - ls > 0.1: i += 0.00001
elif length - ls > 0.01: i += 0.000001
else: break
return i
if __name__ == '__main__':
Archimedes().run()