share/extensions/lindenmayer.py

   1 #!/usr/bin/env python
   2 '''
   3 Copyright (C) 2005 Aaron Spike, aaron@ekips.org
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 '''
  19 import inkex, simplestyle, pturtle
  20
  21 def stripme(s):
  22     return s.strip()
  23
  24 class LSystem(inkex.Effect):
  25     def __init__(self):
  26         inkex.Effect.__init__(self)
  27         self.OptionParser.add_option("-o", "--order",
  28                         action="store", type="int",
  29                         dest="order", default=3,
  30                         help="number of iteration")
  31         self.OptionParser.add_option("-a", "--angle",
  32                         action="store", type="float",
  33                         dest="angle", default=16.0,
  34                         help="angle for turn commands")
  35         self.OptionParser.add_option("-s", "--step",
  36                         action="store", type="float",
  37                         dest="step", default=25.0,
  38                         help="step size")
  39         self.OptionParser.add_option("-x", "--axiom",
  40                         action="store", type="string",
  41                         dest="axiom", default="++F",
  42                         help="initial state of system")
  43         self.OptionParser.add_option("-r", "--rules",
  44                         action="store", type="string",
  45                         dest="rules", default="F=FF-[-F+F+F]+[+F-F-F]",
  46                         help="replacement rules")
  47         self.stack = []
  48         self.turtle = pturtle.pTurtle()
  49     def iterate(self):
  50         self.rules = dict([map(stripme, i.split("=")) for i in self.options.rules.upper().split(";") if i.count("=")==1])
  51         string = self.__recurse(self.options.axiom.upper(),0)
  52         self.__compose_path(string)
  53         return self.turtle.getPath()
  54     def __compose_path(self, string):
  55         for c in string:
  56             if c in 'ABCDEF':
  57                 self.turtle.pd()
  58                 self.turtle.fd(self.options.step)
  59             elif c in 'GHIJKL':
  60                 self.turtle.pu()
  61                 self.turtle.fd(self.options.step)
  62             elif c == '+':
  63                 self.turtle.lt(self.options.angle)
  64             elif c == '-':
  65                 self.turtle.rt(self.options.angle)
  66             elif c == '|':
  67                 self.turtle.lt(180)
  68             elif c == '[':
  69                 self.stack.append([self.turtle.getpos(), self.turtle.getheading()])
  70             elif c == ']':
  71                 self.turtle.pu()
  72                 pos,heading = self.stack.pop()
  73                 self.turtle.setpos(pos)
  74                 self.turtle.setheading(heading)
  75
  76     def __recurse(self,rule,level):
  77         level_string = ''
  78         for c in rule:
  79             if level < self.options.order:
  80                 try:
  81                     level_string = level_string + self.__recurse(self.rules[c],level+1)
  82                 except KeyError:
  83                     level_string = level_string + c
  84             else:
  85                 level_string = level_string + c
  86         return level_string
  87
  88     def effect(self):
  89         new = self.document.createElement('svg:path')
  90         s = {'stroke-linejoin': 'miter', 'stroke-width': '1.0px',
  91             'stroke-opacity': '1.0', 'fill-opacity': '1.0',
  92             'stroke': '#000000', 'stroke-linecap': 'butt',
  93             'fill': 'none'}
  94         new.setAttribute('style', simplestyle.formatStyle(s))
  95         new.setAttribute('d', self.iterate())
  96         self.document.documentElement.appendChild(new)
  97
  98 e = LSystem()
  99 e.affect()
 100