#!/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 # import math import random from math import pi from inkex.utils import math_eval import inkex 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 = math_eval(fx, "t") f2 = math_eval(fy, "t") # 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=30, 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=False, help="Isotropic scaling" ) pars.add_argument("--drawaxis", type=inkex.Boolean, default=False) pars.add_argument("--tab", default="sampling") def effect(self): for node in self.svg.selection: 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()