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Text File  |  2011-07-08  |  3KB  |  82 lines
  1. #!/usr/bin/env python
  2. '''
  3. Copyright (C) 2006 Jean-Francois Barraud, barraud@math.univ-lille1.fr
  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. barraud@math.univ-lille1.fr
  19.  
  20. '''
  21.  
  22. import inkex, cubicsuperpath, bezmisc, pathmodifier
  23. import copy, math, re
  24.  
  25. class RubberStretch(pathmodifier.Diffeo):
  26.     def __init__(self):
  27.         pathmodifier.Diffeo.__init__(self)
  28.         self.OptionParser.add_option("-r", "--ratio",
  29.                         action="store", type="float", 
  30.                         dest="ratio", default=0.5)
  31.         self.OptionParser.add_option("-c", "--curve",
  32.                         action="store", type="float", 
  33.                         dest="curve", default=0.5)
  34.  
  35.     def applyDiffeo(self,bpt,vects=()):
  36.         for v in vects:
  37.             v[0]-=bpt[0]
  38.             v[1]-=bpt[1]
  39.             v[1]*=-1
  40.         bpt[1]*=-1
  41.         a=self.options.ratio/100
  42.         b=min(self.options.curve/100,0.99)
  43.         x0= (self.bbox[0]+self.bbox[1])/2
  44.         y0=-(self.bbox[2]+self.bbox[3])/2
  45.         w,h=(self.bbox[1]-self.bbox[0])/2,(self.bbox[3]-self.bbox[2])/2
  46.         
  47.         x,y=(bpt[0]-x0),(bpt[1]-y0)
  48.         sx=(1+b*(x/w+1)*(x/w-1))*2**(-a)
  49.         sy=(1+b*(y/h+1)*(y/h-1))*2**(-a)
  50.         bpt[0]=x0+x*sy
  51.         bpt[1]=y0+y/sx
  52.         for v in vects:
  53.             dx,dy=v
  54.             dXdx=sy
  55.             dXdy= x*2*b*y/h/h*2**(-a)
  56.             dYdx=-y*2*b*x/w/w*2**(-a)/sx/sx
  57.             dYdy=1/sx
  58.             v[0]=dXdx*dx+dXdy*dy
  59.             v[1]=dYdx*dx+dYdy*dy
  60.     
  61.         #--spherify
  62.         #s=((x*x+y*y)/(w*w+h*h))**(-a/2)
  63.         #bpt[0]=x0+s*x
  64.         #bpt[1]=y0+s*y
  65.         #for v in vects:
  66.         #    dx,dy=v
  67.         #    v[0]=(1-a/2/(x*x+y*y)*2*x*x)*s*dx+( -a/2/(x*x+y*y)*2*y*x)*s*dy
  68.         #    v[1]=( -a/2/(x*x+y*y)*2*x*y)*s*dx+(1-a/2/(x*x+y*y)*2*y*y)*s*dy
  69.     
  70.         for v in vects:
  71.             v[0]+=bpt[0]
  72.             v[1]+=bpt[1]
  73.             v[1]*=-1
  74.         bpt[1]*=-1
  75.  
  76. if __name__ == '__main__':
  77.     e = RubberStretch()
  78.     e.affect()
  79.  
  80.     
  81. # vim: expandtab shiftwidth=4 tabstop=8 softtabstop=4 encoding=utf-8 textwidth=99
  82.