share/extensions/funcplot.py

   1 #!/usr/bin/env python
   2 '''
   3 Copyright (C) 2007 Tavmjong Bah, tavmjong@free.fr
   4 Copyright (C) 2006 Georg Wiora, xorx@quarkbox.de
   5 Copyright (C) 2006 Johan Engelen, johan@shouraizou.nl
   6 Copyright (C) 2005 Aaron Spike, aaron@ekips.org
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21
  22 Changes:
  23  * This program is a modified version of wavy.py by Aaron Spike.
  24  * 22-Dec-2006: Wiora : Added axis and isotropic scaling
  25  * 21-Jun-2007: Tavmjong: Added polar coordinates
  26
  27 '''
  28 import inkex, simplepath, simplestyle
  29 from math import *
  30 from random import *
  31
  32 def drawfunction(xstart, xend, ybottom, ytop, samples, width, height, left, bottom,
  33     fx = "sin(x)", fpx = "cos(x)", fponum = True, times2pi = False, polar = False, isoscale = True, drawaxis = True):
  34
  35     if times2pi == True:
  36         xstart = 2 * pi * xstart
  37         xend   = 2 * pi * xend
  38
  39     # coords and scales based on the source rect
  40     scalex = width / (xend - xstart)
  41     xoff = left
  42     coordx = lambda x: (x - xstart) * scalex + xoff  #convert x-value to coordinate
  43     if polar :  # Set scale so that left side of rectangle is -1, right side is +1.
  44                 # (We can't use xscale for both range and scale.)
  45         centerx = left + width/2.0
  46         polar_scalex = width/2.0
  47         coordx = lambda x: x * polar_scalex + centerx  #convert x-value to coordinate
  48
  49     scaley = height / (ytop - ybottom)
  50     yoff = bottom
  51     coordy = lambda y: (ybottom - y) * scaley + yoff  #convert y-value to coordinate
  52
  53     # Check for isotropic scaling and use smaller of the two scales, correct ranges
  54     if isoscale and not polar:
  55       if scaley<scalex:
  56         # compute zero location
  57         xzero = coordx(0)
  58         # set scale
  59         scalex = scaley
  60         # correct x-offset
  61         xstart = (left-xzero)/scalex
  62         xend = (left+width-xzero)/scalex
  63       else :
  64         # compute zero location
  65         yzero = coordy(0)
  66         # set scale
  67         scaley = scalex
  68         # correct x-offset
  69         ybottom = (yzero-bottom)/scaley
  70         ytop = (bottom+height-yzero)/scaley
  71
  72     # functions specified by the user
  73     if fx != "":
  74         f = eval('lambda x: ' + fx.strip('"'))
  75     if fpx != "":
  76         fp = eval('lambda x: ' + fpx.strip('"'))
  77
  78     # step is the distance between nodes on x
  79     step = (xend - xstart) / (samples-1)
  80     third = step / 3.0
  81     ds = step * 0.001 # Step used in calculating derivatives
  82
  83     a = [] # path array
  84     # add axis
  85     if drawaxis :
  86       # check for visibility of x-axis
  87       if ybottom<=0 and ytop>=0:
  88         # xaxis
  89         a.append(['M ',[left, coordy(0)]])
  90         a.append([' l ',[width, 0]])
  91       # check for visibility of y-axis
  92       if xstart<=0 and xend>=0:
  93         # xaxis
  94         a.append([' M ',[coordx(0),bottom]])
  95         a.append([' l ',[0, -height]])
  96
  97     # initialize function and derivative for 0;
  98     # they are carried over from one iteration to the next, to avoid extra function calculations.
  99     x0 =   xstart
 100     y0 = f(xstart)
 101     if polar :
 102         xp0 = y0 * cos( x0 )
 103         yp0 = y0 * sin( x0 )
 104         x0 = xp0
 105         y0 = yp0
 106     if fponum or polar: # numerical derivative, using 0.001*step as the small differential
 107         x1 = xstart + ds # Second point AFTER first point (Good for first point)
 108         y1 = f(x1)
 109         if polar :
 110             xp1 = y1 * cos( x1 )
 111             yp1 = y1 * sin( x1 )
 112             x1 = xp1
 113             y1 = yp1
 114         dx0 = (x1 - x0)/ds
 115         dy0 = (y1 - y0)/ds
 116     else: # derivative given by the user
 117         dx0 = 1 # Only works for rectangular coordinates
 118         dy0 = fp(xstart)
 119
 120     # Start curve
 121     a.append([' M ',[coordx(x0), coordy(y0)]]) # initial moveto
 122
 123     for i in range(int(samples-1)):
 124         x1 = (i+1) * step + xstart
 125         x2 = x1 - ds # Second point BEFORE first point (Good for last point)
 126         y1 = f(x1)
 127         y2 = f(x2)
 128         if polar :
 129             xp1 = y1 * cos( x1 )
 130             yp1 = y1 * sin( x1 )
 131             xp2 = y2 * cos( x2 )
 132             yp2 = y2 * sin( x2 )
 133             x1 = xp1
 134             y1 = yp1
 135             x2 = xp2
 136             y2 = yp2
 137         if fponum or polar: # numerical derivative
 138             dx1 = (x1 - x2)/ds
 139             dy1 = (y1 - y2)/ds
 140         else: # derivative given by the user
 141             dx1 = 1 # Only works for rectangular coordinates
 142             dy1 = fp(x1)
 143         # create curve
 144         a.append([' C ',
 145                   [coordx(x0 + (dx0 * third)), coordy(y0 + (dy0 * third)),
 146                    coordx(x1 - (dx1 * third)), coordy(y1 - (dy1 * third)),
 147                    coordx(x1),                 coordy(y1)]
 148                   ])
 149         x0  = x1  # Next segment's start is this segments end
 150         y0  = y1
 151         dx0 = dx1 # Assume the function is smooth everywhere, so carry over the derivative too
 152         dy0 = dy1
 153     return a
 154
 155 class FuncPlot(inkex.Effect):
 156     def __init__(self):
 157         inkex.Effect.__init__(self)
 158         self.OptionParser.add_option("--xstart",
 159                         action="store", type="float",
 160                         dest="xstart", default=0.0,
 161                         help="Start x-value")
 162         self.OptionParser.add_option("--xend",
 163                         action="store", type="float",
 164                         dest="xend", default=1.0,
 165                         help="End x-value")
 166         self.OptionParser.add_option("--times2pi",
 167                         action="store", type="inkbool",
 168                         dest="times2pi", default=True,
 169                         help="Multiply x-range by 2*pi")
 170         self.OptionParser.add_option("--polar",
 171                         action="store", type="inkbool",
 172                         dest="polar", default=False,
 173                         help="Plot using polar coordinates")
 174         self.OptionParser.add_option("--ybottom",
 175                         action="store", type="float",
 176                         dest="ybottom", default=-1.0,
 177                         help="y-value of rectangle's bottom")
 178         self.OptionParser.add_option("--ytop",
 179                         action="store", type="float",
 180                         dest="ytop", default=1.0,
 181                         help="y-value of rectangle's top")
 182         self.OptionParser.add_option("-s", "--samples",
 183                         action="store", type="int",
 184                         dest="samples", default=8,
 185                         help="Samples")
 186         self.OptionParser.add_option("--fofx",
 187                         action="store", type="string",
 188                         dest="fofx", default="sin(x)",
 189                         help="f(x) for plotting")
 190         self.OptionParser.add_option("--fponum",
 191                         action="store", type="inkbool",
 192                         dest="fponum", default=True,
 193                         help="Calculate the first derivative numerically")
 194         self.OptionParser.add_option("--fpofx",
 195                         action="store", type="string",
 196                         dest="fpofx", default="cos(x)",
 197                         help="f'(x) for plotting")
 198         self.OptionParser.add_option("--remove",
 199                         action="store", type="inkbool",
 200                         dest="remove", default=True,
 201                         help="If True, source rectangle is removed")
 202         self.OptionParser.add_option("--isoscale",
 203                         action="store", type="inkbool",
 204                         dest="isoscale", default=True,
 205                         help="If True, isotropic scaling is used")
 206         self.OptionParser.add_option("--drawaxis",
 207                         action="store", type="inkbool",
 208                         dest="drawaxis", default=True,
 209                         help="If True, axis are drawn")
 210         self.OptionParser.add_option("--tab",
 211                         action="store", type="string",
 212                         dest="tab", default="sampling",
 213                         help="The selected UI-tab when OK was pressed")
 214         self.OptionParser.add_option("--funcplotuse",
 215                         action="store", type="string",
 216                         dest="funcplotuse", default="",
 217                         help="dummy")
 218         self.OptionParser.add_option("--pythonfunctions",
 219                         action="store", type="string",
 220                         dest="pythonfunctions", default="",
 221                         help="dummy")
 222
 223     def effect(self):
 224         for id, node in self.selected.iteritems():
 225             if node.tag == inkex.addNS('rect','svg'):
 226                 # create new path with basic dimensions of selected rectangle
 227                 newpath = inkex.etree.Element(inkex.addNS('path','svg'))
 228                 x = float(node.get('x'))
 229                 y = float(node.get('y'))
 230                 w = float(node.get('width'))
 231                 h = float(node.get('height'))
 232
 233                 #copy attributes of rect
 234                 s = node.get('style')
 235                 if s:
 236                     newpath.set('style', s)
 237
 238                 t = node.get('transform')
 239                 if t:
 240                     newpath.set('transform', t)
 241
 242                 # top and bottom were exchanged
 243                 newpath.set('d', simplepath.formatPath(
 244                             drawfunction(self.options.xstart,
 245                                 self.options.xend,
 246                                 self.options.ybottom,
 247                                 self.options.ytop,
 248                                 self.options.samples,
 249                                 w,h,x,y+h,
 250                                 self.options.fofx,
 251                                 self.options.fpofx,
 252                                 self.options.fponum,
 253                                 self.options.times2pi,
 254                                 self.options.polar,
 255                                 self.options.isoscale,
 256                                 self.options.drawaxis)))
 257                 newpath.set('title', self.options.fofx)
 258
 259                 #newpath.setAttribute('desc', '!func;' + self.options.fofx + ';'
 260                 #                                      + self.options.fpofx + ';'
 261                 #                                      + `self.options.fponum` + ';'
 262                 #                                      + `self.options.xstart` + ';'
 263                 #                                      + `self.options.xend` + ';'
 264                 #                                      + `self.options.samples`)
 265
 266                 # add path into SVG structure
 267                 node.getparent().append(newpath)
 268                 # option wether to remove the rectangle or not.
 269                 if self.options.remove:
 270                     node.getparent().remove(node)
 271
 272 e = FuncPlot()
 273 e.affect()