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Diffstat (limited to '')
| -rwxr-xr-x | share/extensions/param_curves.py | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/share/extensions/param_curves.py b/share/extensions/param_curves.py new file mode 100755 index 0000000..14a2da0 --- /dev/null +++ b/share/extensions/param_curves.py @@ -0,0 +1,206 @@ +#!/usr/bin/env python +# coding=utf-8 +# +# Copyright (C) 2009 Michel Chatelain. +# 2007 Tavmjong Bah, tavmjong@free.fr +# 2006 Georg Wiora, xorx@quarkbox.de +# 2006 Johan Engelen, johan@shouraizou.nl +# 2005 Aaron Spike, aaron@ekips.org +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +# +# Changes: +# * This program is derived by Michel Chatelain from funcplot.py. +# His changes are in the Public Domain. +# * Michel Chatelain, 17-18 janvier 2009, a partir de funcplot.py +# * 20 janvier 2009 : adaptation a la version 0.46 a partir de la nouvelle version de funcplot.py +# +""" +Parametric Curves has no real description, even in the inx file, which is really odd. +""" + +from math import pi, cos, sin, tan + +import inkex + +def maths_eval(user_function): + """Try and make the eval safer""" + func = 'lambda t: ' + (user_function.strip('"') or 't') + return eval( # pylint: disable=eval-used + func, + { + 'pi': pi, 'sin': sin, 'cos': cos, 'tan': tan, + }, {}) + +def drawfunction(t_start, t_end, xleft, xright, ybottom, ytop, samples, width, height, left, bottom, + fx="cos(3*t)", fy="sin(5*t)", times2pi=False, isoscale=True, drawaxis=True): + if times2pi: + t_start *= 2 * pi + t_end *= 2 * pi + + # coords and scales based on the source rect + scalex = width / (xright - xleft) + xoff = left + coordx = lambda x: (x - xleft) * scalex + xoff # convert x-value to coordinate + scaley = height / (ytop - ybottom) + yoff = bottom + coordy = lambda y: (ybottom - y) * scaley + yoff # convert y-value to coordinate + + # Check for isotropic scaling and use smaller of the two scales, correct ranges + if isoscale: + if scaley < scalex: + # compute zero location + xzero = coordx(0) + # set scale + scalex = scaley + # correct x-offset + xleft = (left - xzero) / scalex + xright = (left + width - xzero) / scalex + else: + # compute zero location + yzero = coordy(0) + # set scale + scaley = scalex + # correct x-offset + ybottom = (yzero - bottom) / scaley + ytop = (bottom + height - yzero) / scaley + + # functions specified by the user + f1 = maths_eval(fx) + f2 = maths_eval(fy) + + # step is increment of t + step = (t_end - t_start) / (samples - 1) + third = step / 3.0 + ds = step * 0.001 # Step used in calculating derivatives + + a = [] # path array + # add axis + if drawaxis: + # check for visibility of x-axis + if ybottom <= 0 <= ytop: + # xaxis + a.append(['M', [left, coordy(0)]]) + a.append(['l', [width, 0]]) + # check for visibility of y-axis + if xleft <= 0 <= xright: + # xaxis + a.append(['M', [coordx(0), bottom]]) + a.append(['l', [0, -height]]) + + # initialize functions and derivatives for 0; + # they are carried over from one iteration to the next, to avoid extra function calculations. + #print("RET: {}".format(f1(1))) + x0 = f1(t_start) + y0 = f2(t_start) + + # numerical derivatives, using 0.001*step as the small differential + t1 = t_start + ds # Second point AFTER first point (Good for first point) + x1 = f1(t1) + y1 = f2(t1) + dx0 = (x1 - x0) / ds + dy0 = (y1 - y0) / ds + + # Start curve + a.append(['M', [coordx(x0), coordy(y0)]]) # initial moveto + for i in range(int(samples - 1)): + t1 = (i + 1) * step + t_start + t2 = t1 - ds # Second point BEFORE first point (Good for last point) + x1 = f1(t1) + x2 = f1(t2) + y1 = f2(t1) + y2 = f2(t2) + + # numerical derivatives + dx1 = (x1 - x2) / ds + dy1 = (y1 - y2) / ds + + # create curve + a.append(['C', + [coordx(x0 + (dx0 * third)), coordy(y0 + (dy0 * third)), + coordx(x1 - (dx1 * third)), coordy(y1 - (dy1 * third)), + coordx(x1), coordy(y1)] + ]) + t0 = t1 # Next segment's start is this segments end + x0 = x1 + y0 = y1 + dx0 = dx1 # Assume the functions are smooth everywhere, so carry over the derivatives too + dy0 = dy1 + return a + + +class ParamCurves(inkex.EffectExtension): + def add_arguments(self, pars): + pars.add_argument("--t_start", type=float, default=0.0, help="Start t-value") + pars.add_argument("--t_end", type=float, default=1.0, help="End t-value") + pars.add_argument("--times2pi", type=inkex.Boolean, default=True, + help="Multiply t-range by 2*pi") + pars.add_argument("--xleft", type=float, default=-1.0, help="x-value of left") + pars.add_argument("--xright", type=float, default=1.0, help="x-value of right") + pars.add_argument("--ybottom", type=float, default=-1.0, help="y-value of bottom") + pars.add_argument("--ytop", type=float, default=1.0, help="y-value of top") + pars.add_argument("-s", "--samples", type=int, default=8, help="Samples") + pars.add_argument("--fofx", default="cos(3*t)", help="fx(t) for plotting") + pars.add_argument("--fofy", default="sin(5*t)", help="fy(t) for plotting") + pars.add_argument("--remove", type=inkex.Boolean, default=True, help="Remove rectangle") + pars.add_argument("--isoscale", type=inkex.Boolean, default=True, help="Isotropic scaling") + pars.add_argument("--drawaxis", type=inkex.Boolean, default=True) + pars.add_argument("--tab", default="sampling") + + def effect(self): + for node in self.svg.selected.values(): + if isinstance(node, inkex.Rectangle): + # create new path with basic dimensions of selected rectangle + newpath = inkex.PathElement() + x = float(node.get('x')) + y = float(node.get('y')) + width = float(node.get('width')) + height = float(node.get('height')) + + # copy attributes of rect + newpath.style = node.style + newpath.transform = node.transform + + # top and bottom were exchanged + newpath.path = \ + drawfunction(self.options.t_start, + self.options.t_end, + self.options.xleft, + self.options.xright, + self.options.ybottom, + self.options.ytop, + self.options.samples, + width, height, x, y + height, + self.options.fofx, + self.options.fofy, + self.options.times2pi, + self.options.isoscale, + self.options.drawaxis) + newpath.set('title', self.options.fofx + " " + self.options.fofy) + + # newpath.set('desc', '!func;' + self.options.fofx + ';' + self.options.fofy + ';' + # + `self.options.t_start` + ';' + # + `self.options.t_end` + ';' + # + `self.options.samples`) + + # add path into SVG structure + node.getparent().append(newpath) + # option whether to remove the rectangle or not. + if self.options.remove: + node.getparent().remove(node) + + +if __name__ == '__main__': + ParamCurves().run() |