#!/usr/bin/env python # coding=utf-8 # # Copyright (C) 2007 Tavmjong Bah, tavmjong@free.fr # Copyright (C) 2006 Georg Wiora, xorx@quarkbox.de # Copyright (C) 2006 Johan Engelen, johan@shouraizou.nl # Copyright (C) 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 a modified version of wavy.py by Aaron Spike. # * 22-Dec-2006: Wiora : Added axis and isotropic scaling # * 21-Jun-2007: Tavmjong: Added polar coordinates # import random import math from math import cos, pi, sin import inkex from inkex import ClipPath, Rectangle EVAL_GLOBALS = {} EVAL_GLOBALS.update(random.__dict__) EVAL_GLOBALS.update(math.__dict__) def drawfunction(xstart, xend, ybottom, ytop, samples, width, height, left, bottom, fx="sin(x)", fpx="cos(x)", fponum=True, times2pi=False, polar=False, isoscale=True, drawaxis=True, endpts=False): if times2pi: xstart = 2 * pi * xstart xend = 2 * pi * xend # coords and scales based on the source rect if xstart == xend: inkex.errormsg("x-interval cannot be zero. Please modify 'Start X value' or 'End X value'") return [] scalex = width / (xend - xstart) xoff = left coordx = lambda x: (x - xstart) * scalex + xoff # convert x-value to coordinate if polar: # Set scale so that left side of rectangle is -1, right side is +1. # (We can't use xscale for both range and scale.) centerx = left + width / 2.0 polar_scalex = width / 2.0 coordx = lambda x: x * polar_scalex + centerx # convert x-value to coordinate if ytop == ybottom: inkex.errormsg("y-interval cannot be zero. Please modify 'Y value of rectangle's top' or 'Y value of rectangle's bottom'") return [] 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 and not polar: if scaley < scalex: # compute zero location xzero = coordx(0) # set scale scalex = scaley # correct x-offset xstart = (left - xzero) / scalex xend = (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 try: if fx != "": f = eval('lambda x: ' + fx, EVAL_GLOBALS, {}) if fpx != "": fp = eval('lambda x: ' + fpx, EVAL_GLOBALS, {}) # handle incomplete/invalid function gracefully except SyntaxError: return [] # step is the distance between nodes on x step = (xend - xstart) / (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 xstart <= 0 <= xend: # xaxis a.append(['M', [coordx(0), bottom]]) a.append(['l', [0, -height]]) # initialize function and derivative for 0; # they are carried over from one iteration to the next, to avoid extra function calculations. x0 = xstart y0 = f(xstart) if polar: xp0 = y0 * cos(x0) yp0 = y0 * sin(x0) x0 = xp0 y0 = yp0 if fponum or polar: # numerical derivative, using 0.001*step as the small differential x1 = xstart + ds # Second point AFTER first point (Good for first point) y1 = f(x1) if polar: xp1 = y1 * cos(x1) yp1 = y1 * sin(x1) x1 = xp1 y1 = yp1 dx0 = (x1 - x0) / ds dy0 = (y1 - y0) / ds else: # derivative given by the user dx0 = 1 # Only works for rectangular coordinates dy0 = fp(xstart) # Start curve if endpts: a.append(['M', [left, coordy(0)]]) a.append(['L', [coordx(x0), coordy(y0)]]) else: a.append(['M', [coordx(x0), coordy(y0)]]) # initial moveto for i in range(int(samples - 1)): x1 = (i + 1) * step + xstart x2 = x1 - ds # Second point BEFORE first point (Good for last point) y1 = f(x1) y2 = f(x2) if polar: xp1 = y1 * cos(x1) yp1 = y1 * sin(x1) xp2 = y2 * cos(x2) yp2 = y2 * sin(x2) x1 = xp1 y1 = yp1 x2 = xp2 y2 = yp2 if fponum or polar: # numerical derivative dx1 = (x1 - x2) / ds dy1 = (y1 - y2) / ds else: # derivative given by the user dx1 = 1 # Only works for rectangular coordinates dy1 = fp(x1) # 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)] ]) x0 = x1 # Next segment's start is this segments end y0 = y1 dx0 = dx1 # Assume the function is smooth everywhere, so carry over the derivative too dy0 = dy1 if endpts: a.append(['L', [left + width, coordy(0)]]) return a class FuncPlot(inkex.EffectExtension): def add_arguments(self, pars): pars.add_argument("--tab") pars.add_argument("--xstart", type=float, default=0.0, help="Start x-value") pars.add_argument("--xend", type=float, default=1.0, help="End x-value") pars.add_argument("--times2pi", type=inkex.Boolean, default=True, help="* x-range by 2*pi") pars.add_argument("--polar", type=inkex.Boolean, default=False, help="Use polar coords") pars.add_argument("--ybottom", type=float, default=-1.0, help="y-value of rect's bottom") pars.add_argument("--ytop", type=float, default=1.0, help="y-value of rectangle's top") pars.add_argument("--samples", type=int, default=8, help="Samples") pars.add_argument("--fofx", default="sin(x)", help="f(x) for plotting") pars.add_argument("--fponum", type=inkex.Boolean, default=True, help="Numerical 1st deriv") pars.add_argument("--fpofx", default="cos(x)", help="f'(x) for plotting") pars.add_argument("--clip", type=inkex.Boolean, default=False, help="Clip with source rect") pars.add_argument("--remove", type=inkex.Boolean, default=True, help="Remove source rect") pars.add_argument("--isoscale", type=inkex.Boolean, default=True, help="Isotropic scaling") pars.add_argument("--drawaxis", type=inkex.Boolean, default=True, help="Draw axis") pars.add_argument("--endpts", type=inkex.Boolean, default=False, help="Add end points") def effect(self): newpath = None for node in self.svg.selected.values(): if isinstance(node, Rectangle): # create new path with basic dimensions of selected rectangle newpath = inkex.PathElement() x = float(node.get('x')) y = float(node.get('y')) w = float(node.get('width')) h = 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.xstart, self.options.xend, self.options.ybottom, self.options.ytop, self.options.samples, w, h, x, y + h, self.options.fofx, self.options.fpofx, self.options.fponum, self.options.times2pi, self.options.polar, self.options.isoscale, self.options.drawaxis, self.options.endpts) newpath.set('title', self.options.fofx) # add path into SVG structure node.getparent().append(newpath) # option whether to clip the path with rect or not. if self.options.clip: clip = self.svg.defs.add(ClipPath()) clip.set_random_id() clip.append(node.copy()) newpath.set('clip-path', 'url(#' + clip.get_id() + ')') # option whether to remove the rectangle or not. if self.options.remove: node.getparent().remove(node) if newpath is None: inkex.errormsg("Please select a rectangle") if __name__ == '__main__': FuncPlot().run()