share/extensions/fractalize.py

   1 #!/usr/bin/env python \r
   2 '''\r
   3 Copyright (C) 2005 Carsten Goetze c.goetze@tu-bs.de\r
   4 \r
   5 This program is free software; you can redistribute it and/or modify\r
   6 it under the terms of the GNU General Public License as published by\r
   7 the Free Software Foundation; either version 2 of the License, or\r
   8 (at your option) any later version.\r
   9 \r
  10 This program is distributed in the hope that it will be useful,\r
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  13 GNU General Public License for more details.\r
  14 \r
  15 You should have received a copy of the GNU General Public License\r
  16 along with this program; if not, write to the Free Software\r
  17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
  18 '''\r
  19 import random, math, inkex, simplestyle, simplepath\r
  20 \r
  21 def calculateSubdivision(x1,y1,x2,y2,smoothness):\r
  22         """ Calculate the vector from (x1,y1) to (x2,y2) """\r
  23         x3 = x2 - x1\r
  24         y3 = y2 - y1\r
  25         """ Calculate the point half-way between the two points """\r
  26         hx = x1 + x3/2\r
  27         hy = y1 + y3/2\r
  28         """ Calculate normalized vector perpendicular to the vector (x3,y3) """\r
  29         length = math.sqrt(x3*x3 + y3*y3)\r
  30         nx = -y3/length\r
  31         ny = x3/length\r
  32         """ Scale perpendicular vector by random factor """\r
  33         r = random.uniform(-length/(1+smoothness),length/(1+smoothness))\r
  34         nx = nx * r\r
  35         ny = ny * r\r
  36         """ add scaled perpendicular vector to the half-way point to get the final\r
  37             displaced subdivision point """\r
  38         x = hx + nx\r
  39         y = hy + ny\r
  40         return [x, y]\r
  41 \r
  42 class PathFractalize(inkex.Effect):\r
  43         def __init__(self):\r
  44                 inkex.Effect.__init__(self)\r
  45                 self.OptionParser.add_option("-s", "--subdivs",\r
  46                                                 action="store", type="int", \r
  47                                                 dest="subdivs", default="6",\r
  48                                                 help="Number of subdivisons")\r
  49                 self.OptionParser.add_option("-f", "--smooth",\r
  50                                                 action="store", type="float", \r
  51                                                 dest="smooth", default="4.0",\r
  52                                                 help="Smoothness of the subdivision")\r
  53         def effect(self):\r
  54                 for id, node in self.selected.iteritems():\r
  55                         if node.tagName == 'path':\r
  56                                 d = node.attributes.getNamedItem('d')\r
  57                                 p = simplepath.parsePath(d.value)\r
  58                                 new = self.document.createElement('svg:path')\r
  59                                 try:\r
  60                                         t = node.attributes.getNamedItem('transform').value\r
  61                                         new.setAttribute('transform', t)\r
  62                                 except AttributeError:\r
  63                                         pass\r
  64 \r
  65                                 s = simplestyle.parseStyle(node.attributes.getNamedItem('style').value)\r
  66                                 new.setAttribute('style', simplestyle.formatStyle(s))\r
  67                                 \r
  68                                 a = []\r
  69                                 p = simplepath.parsePath(node.attributes.getNamedItem('d').value)\r
  70                                 first = 1\r
  71                                 for cmd,params in p:\r
  72                                         if cmd != 'Z':\r
  73                                           if first == 1:\r
  74                                             x1 = params[-2]\r
  75                                             y1 = params[-1]\r
  76                                             a.append(['M',params[-2:]])\r
  77                                             first = 2\r
  78                                           else :\r
  79                                             x2 = params[-2]\r
  80                                             y2 = params[-1]\r
  81                                             self.fractalize(a,x1,y1,x2,y2,self.options.subdivs,self.options.smooth)\r
  82                                             x1 = x2\r
  83                                             y1 = y2\r
  84                                             a.append(['L',params[-2:]])\r
  85 \r
  86                                 new.setAttribute('d', simplepath.formatPath(a))\r
  87                                 node.parentNode.appendChild(new)\r
  88                                 node.parentNode.removeChild(node)\r
  89 \r
  90         def fractalize(self,a,x1,y1,x2,y2,s,f):\r
  91                 subdivPoint = calculateSubdivision(x1,y1,x2,y2,f)\r
  92                 \r
  93                 if s > 0 :\r
  94                   """ recursively subdivide the segment left of the subdivision point """\r
  95                   self.fractalize(a,x1,y1,subdivPoint[-2],subdivPoint[-1],s-1,f)\r
  96                   a.append(['L',subdivPoint])\r
  97                   """ recursively subdivide the segment right of the subdivision point """\r
  98                   self.fractalize(a,subdivPoint[-2],subdivPoint[-1],x2,y2,s-1,f)\r
  99              \r
 100 e = PathFractalize()\r
 101 e.affect()\r
 102 \r