share/extensions/voronoi2svg.py

	voronoi2svg.py revision 2a1cece0da69dfd97d4d6d78c1e978cc7f969118
#!/usr/bin/env python
"""

voronoi2svg.py
Create Voronoi diagram from seeds (midpoints of selected objects)

- Voronoi Diagram algorithm and C code by Steven Fortune, 1987, http://ect.bell-labs.com/who/sjf/
- Python translation to file voronoi.py by Bill Simons, 2005, http://www.oxfish.com/

Copyright (C) 2011 Vincent Nivoliers and contributors

Contributors
  ~suv, <suv-sf@users.sf.net>

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

"""
import sys, os
import inkex, simplestyle, simplepath, simpletransform
import voronoi
import gettext
_ = gettext.gettext

class Point:
  def __init__(self,x,y):
    self.x = x
    self.y = y

class Voronoi2svg(inkex.Effect):
  def __init__(self):
    inkex.Effect.__init__(self)

    #{{{ Additional options

    self.OptionParser.add_option(
      '--diagram-type',
      action = 'store',
      type = 'choice', choices=['Voronoi','Delaunay','Both'],
      default = 'Voronoi',
      dest='diagramType',
      help = 'Defines the type of the diagram')
    self.OptionParser.add_option(
      '--clip-box',
      action = 'store',
      type = 'choice', choices=['Page','Automatic from seeds'],
      default = 'Page',
      dest='clipBox',
      help = 'Defines the area bounding the Voronoi diagram')
    self.OptionParser.add_option(
      '--show-clip-box',
      action = 'store',
      type = 'inkbool',
      default = False,
      dest='showClipBox',
      help = 'Set this to true to write the bounding box of the bounding area')

    #}}}

  #{{{ Clipping a line by a bounding box
  def dot(self,x,y):
    return x[0]*y[0] + x[1]*y[1]

  def intersectLineSegment(self,line,v1,v2):
    s1 = self.dot(line,v1) - line[2]
    s2 = self.dot(line,v2) - line[2]
    if s1*s2 > 0:
      return (0,0,False)
    else:
      tmp = self.dot(line,v1)-self.dot(line,v2)
      if tmp == 0:
        return(0,0,False)
      u = (line[2]-self.dot(line,v2))/tmp
      v = 1-u
      return (u*v1[0]+v*v2[0],u*v1[1]+v*v2[1],True)

  def clipEdge(self,vertices, lines, edge, bbox):
    #bounding box corners
    bbc = []
    bbc.append((bbox[0],bbox[2]))
    bbc.append((bbox[1],bbox[2]))
    bbc.append((bbox[1],bbox[3]))
    bbc.append((bbox[0],bbox[3]))

    #record intersections of the line with bounding box edges
    line = (lines[edge[0]])
    interpoints = []
    for i in range(4):
      p = self.intersectLineSegment(line,bbc[i],bbc[(i+1)%4])
      if (p[2]):
        interpoints.append(p)

    #if the edge has no intersection, return empty intersection
    if (len(interpoints)<2):
      return []

    if (len(interpoints)>2): #happens when the edge crosses the corner of the box
      interpoints = list(set(interpoints)) #remove doubles

    #points of the edge
    v1 = vertices[edge[1]]
    interpoints.append((v1[0],v1[1],False))
    v2 = vertices[edge[2]]
    interpoints.append((v2[0],v2[1],False))

    #sorting the points in the widest range to get them in order on the line
    minx = interpoints[0][0]
    maxx = interpoints[0][0]
    miny = interpoints[0][1]
    maxy = interpoints[0][1]
    for point in interpoints:
      minx = min(point[0],minx)
      maxx = max(point[0],maxx)
      miny = min(point[1],miny)
      maxy = max(point[1],maxy)

    if (maxx-minx) > (maxy-miny):
      interpoints.sort()
    else:
      interpoints.sort(key=lambda pt: pt[1])

    start = []
    inside = False #true when the part of the line studied is in the clip box
    startWrite = False #true when the part of the line is in the edge segment
    for point in interpoints:
      if point[2]: #The point is a bounding box intersection
        if inside:
          if startWrite:
            return [[start[0],start[1]],[point[0],point[1]]]
          else:
            return []
        else:
          if startWrite:
            start = point
        inside = not inside
      else: #The point is a segment endpoint
        if startWrite:
          if inside:
            #a vertex ends the line inside the bounding box
            return [[start[0],start[1]],[point[0],point[1]]]
          else:
            return []
        else:
          if inside:
            start = point
        startWrite = not startWrite

  #}}}

  #{{{ Transformation helpers

  def invertTransform(self,mat):
    det = mat[0][0]*mat[1][1] - mat[0][1]*mat[1][0]
    if det !=0: #det is 0 only in case of 0 scaling
      #invert the rotation/scaling part
      a11 =  mat[1][1]/det
      a12 = -mat[0][1]/det
      a21 = -mat[1][0]/det
      a22 =  mat[0][0]/det

      #invert the translational part
      a13 = -(a11*mat[0][2] + a12*mat[1][2])
      a23 = -(a21*mat[0][2] + a22*mat[1][2])

      return [[a11,a12,a13],[a21,a22,a23]]
    else:
      return[[0,0,-mat[0][2]],[0,0,-mat[1][2]]]

  def getGlobalTransform(self,node):
    parent = node.getparent()
    myTrans = simpletransform.parseTransform(node.get('transform'))
    if myTrans:
      if parent is not None:
        parentTrans = self.getGlobalTransform(parent)
        if parentTrans:
          return simpletransform.composeTransform(parentTrans,myTrans)
        else:
          return myTrans
    else:
      if parent is not None:
        return self.getGlobalTransform(parent)
      else:
        return None


  #}}}

  def effect(self):

    #{{{ Check that elements have been selected

    if len(self.options.ids) == 0:
      inkex.errormsg("Please select seed objects!")
      return

    #}}}

    #{{{ Drawing styles

    linestyle = {
        'stroke'    : '#000000',
        'linewidth' : '1',
        'fill'      : 'none'
        }

    facestyle = {
        'stroke'    : '#ff0000',
        'linewidth' : '1',
        'fill'      : 'none'
        }

    #}}}

    #{{{ Handle the transformation of the current group
    parentGroup = self.getParentNode(self.selected[self.options.ids[0]])

    trans = self.getGlobalTransform(parentGroup)
    invtrans = None
    if trans:
      invtrans = self.invertTransform(trans)

    #}}}

    #{{{ Recovery of the selected objects

    pts = []
    nodes = []
    seeds = []


    for id in self.options.ids:
      node = self.selected[id]
      nodes.append(node)
      bbox = simpletransform.computeBBox([node])
      if bbox:
        cx = 0.5*(bbox[0]+bbox[1])
        cy = 0.5*(bbox[2]+bbox[3])
        pt = [cx,cy]
        if trans:
          simpletransform.applyTransformToPoint(trans,pt)
        pts.append(Point(pt[0],pt[1]))
        seeds.append(Point(cx,cy))

    #}}}

    #{{{ Creation of groups to store the result

    if self.options.diagramType != 'Delaunay':
      # Voronoi
      groupVoronoi = inkex.etree.SubElement(parentGroup,inkex.addNS('g','svg'))
      groupVoronoi.set(inkex.addNS('label', 'inkscape'), 'Voronoi')
      if invtrans:
        simpletransform.applyTransformToNode(invtrans,groupVoronoi)
    if self.options.diagramType != 'Voronoi':
      # Delaunay
      groupDelaunay = inkex.etree.SubElement(parentGroup,inkex.addNS('g','svg'))
      groupDelaunay.set(inkex.addNS('label', 'inkscape'), 'Delaunay')

    #}}}

    #{{{ Clipping box handling

    if self.options.diagramType != 'Delaunay':
      #Clipping bounding box creation
      gBbox = simpletransform.computeBBox(nodes)

      #Clipbox is the box to which the Voronoi diagram is restricted
      clipBox = ()
      if self.options.clipBox == 'Page':
        svg = self.document.getroot()
        w = inkex.unittouu(svg.get('width'))
        h = inkex.unittouu(svg.get('height'))
        clipBox = (0,w,0,h)
      else:
        clipBox = (2*gBbox[0]-gBbox[1],
                   2*gBbox[1]-gBbox[0],
                   2*gBbox[2]-gBbox[3],
                   2*gBbox[3]-gBbox[2])

      #Safebox adds points so that no Voronoi edge in clipBox is infinite
      safeBox = (2*clipBox[0]-clipBox[1],
                 2*clipBox[1]-clipBox[0],
                 2*clipBox[2]-clipBox[3],
                 2*clipBox[3]-clipBox[2])
      pts.append(Point(safeBox[0],safeBox[2]))
      pts.append(Point(safeBox[1],safeBox[2]))
      pts.append(Point(safeBox[1],safeBox[3]))
      pts.append(Point(safeBox[0],safeBox[3]))

      if self.options.showClipBox:
        #Add the clip box to the drawing
        rect = inkex.etree.SubElement(groupVoronoi,inkex.addNS('rect','svg'))
        rect.set('x',str(clipBox[0]))
        rect.set('y',str(clipBox[2]))
        rect.set('width',str(clipBox[1]-clipBox[0]))
        rect.set('height',str(clipBox[3]-clipBox[2]))
        rect.set('style',simplestyle.formatStyle(linestyle))

    #}}}

    #{{{ Voronoi diagram generation

    if self.options.diagramType != 'Delaunay':
      vertices,lines,edges = voronoi.computeVoronoiDiagram(pts)
      for edge in edges:
        line = edge[0]
        vindex1 = edge[1]
        vindex2 = edge[2]
        if (vindex1 <0) or (vindex2 <0):
          continue # infinite lines have no need to be handled in the clipped box
        else:
          segment = self.clipEdge(vertices,lines,edge,clipBox)
          #segment = [vertices[vindex1],vertices[vindex2]] # deactivate clipping
          if len(segment)>1:
            v1 = segment[0]
            v2 = segment[1]
            cmds = [['M',[v1[0],v1[1]]],['L',[v2[0],v2[1]]]]
            path = inkex.etree.Element(inkex.addNS('path','svg'))
            path.set('d',simplepath.formatPath(cmds))
            path.set('style',simplestyle.formatStyle(linestyle))
            groupVoronoi.append(path)

    if self.options.diagramType != 'Voronoi':
      triangles = voronoi.computeDelaunayTriangulation(seeds)
      for triangle in triangles:
        p1 = seeds[triangle[0]]
        p2 = seeds[triangle[1]]
        p3 = seeds[triangle[2]]
        cmds = [['M',[p1.x,p1.y]],
                ['L',[p2.x,p2.y]],
                ['L',[p3.x,p3.y]],
                ['Z',[]]]
        path = inkex.etree.Element(inkex.addNS('path','svg'))
        path.set('d',simplepath.formatPath(cmds))
        path.set('style',simplestyle.formatStyle(facestyle))
        groupDelaunay.append(path)

    #}}}


if __name__ == "__main__":
  e = Voronoi2svg()
  e.affect()


# vim: expandtab shiftwidth=2 tabstop=2 softtabstop=2 fileencoding=utf-8 textwidth=99