236 lines
8.1 KiB
Python
Executable file
236 lines
8.1 KiB
Python
Executable file
#!/usr/bin/env python3
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# coding=utf-8
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#
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# Copyright (C) 2009 Michel Chatelain.
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# 2007 Tavmjong Bah, tavmjong@free.fr
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# 2006 Georg Wiora, xorx@quarkbox.de
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# 2006 Johan Engelen, johan@shouraizou.nl
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# 2005 Aaron Spike, aaron@ekips.org
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#
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# Changes:
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# * This program is derived by Michel Chatelain from funcplot.py.
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# His changes are in the Public Domain.
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# * Michel Chatelain, 17-18 janvier 2009, a partir de funcplot.py
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# * 20 janvier 2009 : adaptation a la version 0.46 a partir de la nouvelle version de funcplot.py
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#
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import math
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import random
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from math import pi
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from inkex.utils import math_eval
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import inkex
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def drawfunction(
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t_start,
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t_end,
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xleft,
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xright,
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ybottom,
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ytop,
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samples,
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width,
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height,
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left,
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bottom,
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fx="cos(3*t)",
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fy="sin(5*t)",
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times2pi=False,
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isoscale=True,
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drawaxis=True,
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):
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if times2pi:
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t_start *= 2 * pi
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t_end *= 2 * pi
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# coords and scales based on the source rect
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scalex = width / (xright - xleft)
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xoff = left
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coordx = lambda x: (x - xleft) * scalex + xoff # convert x-value to coordinate
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scaley = height / (ytop - ybottom)
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yoff = bottom
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coordy = lambda y: (ybottom - y) * scaley + yoff # convert y-value to coordinate
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# Check for isotropic scaling and use smaller of the two scales, correct ranges
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if isoscale:
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if scaley < scalex:
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# compute zero location
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xzero = coordx(0)
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# set scale
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scalex = scaley
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# correct x-offset
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xleft = (left - xzero) / scalex
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xright = (left + width - xzero) / scalex
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else:
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# compute zero location
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yzero = coordy(0)
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# set scale
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scaley = scalex
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# correct x-offset
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ybottom = (yzero - bottom) / scaley
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ytop = (bottom + height - yzero) / scaley
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# functions specified by the user
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f1 = math_eval(fx, "t")
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f2 = math_eval(fy, "t")
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# step is increment of t
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step = (t_end - t_start) / (samples - 1)
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third = step / 3.0
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ds = step * 0.001 # Step used in calculating derivatives
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a = [] # path array
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# add axis
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if drawaxis:
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# check for visibility of x-axis
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if ybottom <= 0 <= ytop:
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# xaxis
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a.append(["M", [left, coordy(0)]])
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a.append(["l", [width, 0]])
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# check for visibility of y-axis
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if xleft <= 0 <= xright:
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# xaxis
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a.append(["M", [coordx(0), bottom]])
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a.append(["l", [0, -height]])
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# initialize functions and derivatives for 0;
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# they are carried over from one iteration to the next, to avoid extra function calculations.
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# print("RET: {}".format(f1(1)))
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x0 = f1(t_start)
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y0 = f2(t_start)
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# numerical derivatives, using 0.001*step as the small differential
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t1 = t_start + ds # Second point AFTER first point (Good for first point)
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x1 = f1(t1)
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y1 = f2(t1)
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dx0 = (x1 - x0) / ds
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dy0 = (y1 - y0) / ds
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# Start curve
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a.append(["M", [coordx(x0), coordy(y0)]]) # initial moveto
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for i in range(int(samples - 1)):
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t1 = (i + 1) * step + t_start
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t2 = t1 - ds # Second point BEFORE first point (Good for last point)
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x1 = f1(t1)
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x2 = f1(t2)
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y1 = f2(t1)
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y2 = f2(t2)
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# numerical derivatives
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dx1 = (x1 - x2) / ds
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dy1 = (y1 - y2) / ds
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# create curve
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a.append(
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[
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"C",
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[
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coordx(x0 + (dx0 * third)),
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coordy(y0 + (dy0 * third)),
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coordx(x1 - (dx1 * third)),
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coordy(y1 - (dy1 * third)),
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coordx(x1),
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coordy(y1),
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],
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]
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)
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t0 = t1 # Next segment's start is this segments end
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x0 = x1
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y0 = y1
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dx0 = dx1 # Assume the functions are smooth everywhere, so carry over the derivatives too
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dy0 = dy1
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return a
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class ParamCurves(inkex.EffectExtension):
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def add_arguments(self, pars):
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pars.add_argument("--t_start", type=float, default=0.0, help="Start t-value")
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pars.add_argument("--t_end", type=float, default=1.0, help="End t-value")
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pars.add_argument(
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"--times2pi",
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type=inkex.Boolean,
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default=True,
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help="Multiply t-range by 2*pi",
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)
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pars.add_argument("--xleft", type=float, default=-1.0, help="x-value of left")
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pars.add_argument("--xright", type=float, default=1.0, help="x-value of right")
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pars.add_argument(
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"--ybottom", type=float, default=-1.0, help="y-value of bottom"
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)
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pars.add_argument("--ytop", type=float, default=1.0, help="y-value of top")
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pars.add_argument("-s", "--samples", type=int, default=30, help="Samples")
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pars.add_argument("--fofx", default="cos(3*t)", help="fx(t) for plotting")
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pars.add_argument("--fofy", default="sin(5*t)", help="fy(t) for plotting")
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pars.add_argument(
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"--remove", type=inkex.Boolean, default=True, help="Remove rectangle"
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)
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pars.add_argument(
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"--isoscale", type=inkex.Boolean, default=False, help="Isotropic scaling"
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)
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pars.add_argument("--drawaxis", type=inkex.Boolean, default=False)
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pars.add_argument("--tab", default="sampling")
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def effect(self):
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for node in self.svg.selection:
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if isinstance(node, inkex.Rectangle):
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# create new path with basic dimensions of selected rectangle
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newpath = inkex.PathElement()
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x = float(node.get("x"))
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y = float(node.get("y"))
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width = float(node.get("width"))
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height = float(node.get("height"))
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# copy attributes of rect
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newpath.style = node.style
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newpath.transform = node.transform
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# top and bottom were exchanged
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newpath.path = drawfunction(
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self.options.t_start,
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self.options.t_end,
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self.options.xleft,
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self.options.xright,
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self.options.ybottom,
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self.options.ytop,
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self.options.samples,
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width,
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height,
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x,
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y + height,
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self.options.fofx,
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self.options.fofy,
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self.options.times2pi,
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self.options.isoscale,
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self.options.drawaxis,
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)
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newpath.set("title", self.options.fofx + " " + self.options.fofy)
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# newpath.set('desc', '!func;' + self.options.fofx + ';' + self.options.fofy + ';'
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# + `self.options.t_start` + ';'
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# + `self.options.t_end` + ';'
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# + `self.options.samples`)
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# add path into SVG structure
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node.getparent().append(newpath)
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# option whether to remove the rectangle or not.
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if self.options.remove:
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node.getparent().remove(node)
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if __name__ == "__main__":
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ParamCurves().run()
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