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Diffstat (limited to 'share/extensions/funcplot.py')
| -rwxr-xr-x | share/extensions/funcplot.py | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/share/extensions/funcplot.py b/share/extensions/funcplot.py new file mode 100755 index 0000000..4b24191 --- /dev/null +++ b/share/extensions/funcplot.py @@ -0,0 +1,247 @@ +#!/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() |