Logo Search packages:      
Sourcecode: inkscape version File versions

rubberstretch.py

#!/usr/bin/env python
'''
Copyright (C) 2006 Jean-Francois Barraud, barraud@math.univ-lille1.fr

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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
barraud@math.univ-lille1.fr

'''

import inkex, cubicsuperpath, bezmisc, pathmodifier
import copy, math, re, random, xml.xpath

class RubberStretch(pathmodifier.Diffeo):
    def __init__(self):
        pathmodifier.Diffeo.__init__(self)
        self.OptionParser.add_option("-r", "--ratio",
                        action="store", type="float", 
                        dest="ratio", default=0.5)
        self.OptionParser.add_option("-c", "--curve",
                        action="store", type="float", 
                        dest="curve", default=0.5)

    def applyDiffeo(self,bpt,vects=()):
      for v in vects:
          v[0]-=bpt[0]
          v[1]-=bpt[1]
          v[1]*=-1
      bpt[1]*=-1
      a=self.options.ratio/100
      b=min(self.options.curve/100,0.99)
      x0= (self.bbox[0]+self.bbox[1])/2
      y0=-(self.bbox[2]+self.bbox[3])/2
      w,h=(self.bbox[1]-self.bbox[0])/2,(self.bbox[3]-self.bbox[2])/2
      
      x,y=(bpt[0]-x0),(bpt[1]-y0)
            sx=(1+b*(x/w+1)*(x/w-1))*2**(-a)
      sy=(1+b*(y/h+1)*(y/h-1))*2**(-a)
      bpt[0]=x0+x*sy
      bpt[1]=y0+y/sx
      for v in vects:
          dx,dy=v
          dXdx=sy
          dXdy= x*2*b*y/h/h*2**(-a)
          dYdx=-y*2*b*x/w/w*2**(-a)/sx/sx
          dYdy=1/sx
          v[0]=dXdx*dx+dXdy*dy
          v[1]=dYdx*dx+dYdy*dy

      #--spherify
#     s=((x*x+y*y)/(w*w+h*h))**(-a/2)
#     bpt[0]=x0+s*x
#     bpt[1]=y0+s*y
#     for v in vects:
#         dx,dy=v
#         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
#         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

      for v in vects:
          v[0]+=bpt[0]
          v[1]+=bpt[1]
          v[1]*=-1
      bpt[1]*=-1

e = RubberStretch()
e.affect()

             

Generated by  Doxygen 1.6.0   Back to index