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mightyscape-1.1-deprecated/extensions/fablabchemnitz/affine_spirals/affine_spirals.py

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2021-07-23 02:36:56 +02:00
#!/usr/bin/env python3
import inkex
from lxml import etree
from math import cos, sin, pi, exp
__version__ = '0.1'
def line(npts=40, x0=0, y0=0, delta=.5, sgn=1):
#returns a list of points on a line (y = +/- x + c) starting at x0,y0
return [ (x0 + delta*t, y0 + sgn*delta*t) for t in range(npts)]
def ff(v, ww=.25, ds=.4):
#covering map from R^2 ro punctured plane
x,y = v
r,u = exp(-ds*x), cos(pi*ww*y) + 1J*sin(pi*ww*y)
return r*u
def mk_plugs(pts):
#returns a list of complex representing a plug type segment
segs = [fit_plug(end_pts) for end_pts in zip(pts,pts[1:]) ]
tmp = []
for seg in segs:
tmp.extend(seg)
return tmp
def fit_plug(ss):
a,b = ss
rot = complex(b-a)
pts = [0,.45,.4 + .15*1J, .6 + .15*1J, .55, 1]
return [rot*z + a for z in pts]
def pts2curve(cplxs):
'''makes a polyline path element from a list of complex
'''
def cplx2pt(z):
return (z.real,z.imag)
scale = 200
data = [cplx2pt( scale*z ) for z in cplxs ]
pth = [ '%.2f, %.2f '%z for z in data]
return 'M '+ ''.join(pth)
class AffineSpirals(inkex.EffectExtension):
def add_arguments(self, pars):
pars.add_argument("--num_lines", type=int, default=3)
pars.add_argument("--num_petals", type=int, default=3)
pars.add_argument("--shrink_ratio", type=float, default=3)
pars.add_argument("--active-tab", default='title')
def calc_unit_factor(self):
unit_factor = self.svg.unittouu(str(1.0) + self.options.units)
return unit_factor
def effect(self):
path_stroke = '#DD0000' # take color from tab3
path_fill = 'none' # no fill - just a line
path_stroke_width = 1. # can also be in form '0.6mm'
page_id = self.options.active_tab # sometimes wrong the very first time
styles = [ {'stroke': path_stroke , 'fill': 'none', 'stroke-width': path_stroke_width},
{'stroke': 'none', 'fill': '#FFFF00', 'stroke-width': 0}]
styles = [str(inkex.Style(x)) for x in styles]
# This finds center of current view in inkscape
t = 'translate(%s,%s)' % (self.svg.namedview.center[0], self.svg.namedview.center[1])
# Make a nice useful name
g_attribs = {inkex.addNS('label','inkscape'): 'koch',
inkex.addNS('transform-center-x','inkscape'): str(0),
inkex.addNS('transform-center-y','inkscape'): str(0),
'transform': t,
'style' : styles[1],
'info':'N: '+str(self.options.num_lines) }
topgroup = etree.SubElement(self.svg.get_current_layer(), 'g', g_attribs)
NN = 2*self.options.num_lines
NP = self.options.num_petals
SF = 2*self.options.shrink_ratio
payload = []
for y in range(-NP,NP):
mpts = [ff(z,ww=1./NP, ds=SF) for z in line(npts=NN, y0=y)]
payload.append(mk_plugs(mpts))
mpts = [ff(z,ww=1./NP, ds=SF) for z in line(npts=NN, y0=y,sgn=-1 )]
payload.append(mk_plugs(mpts))
payload = [pts2curve(cc) for cc in payload]
payload = ' '.join(payload)
curve_attribs = { 'style': styles[0], 'd': payload}
etree.SubElement(topgroup, inkex.addNS('path','svg'), curve_attribs)
if __name__ == '__main__':
AffineSpirals().run()