CGAL users discussion list

[jiatao83 <>]

Dear All:

   Hi, I am a new learner in CGAL. I have written a program with CGAL to caculate the Straight Skeleton of Polygons with holes. The input Polygon with holes have 27 boundaries(both outer boundary and inner boundaries), plz see the following table for details about the 27 boundaries:

     Boundary Type         Number of Points

     outer boundary            167

     inner boundary1            23

     inner boundary2            29

     inner boundary3            38

     inner boundary4            52

     inner boundary5            89

     inner boundary6            93

     inner boundary7            69

     inner boundary8            38

     inner boundary9            39

     inner boundary10           32

     inner boundary11           37

      ......                    ..

   The others(12-26) have about the number of 45 Points. And most of these boundaries have reflex vertex.

   The code followed:

--------------------------------------------------------------------------------------------------------

   typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;

   typedef Kernel::Point_2 Point_2;

   typedef CGAL::Straight_skeleton_2<Kernel> Ss;

   typedef Ss::Halfedge_iterator Halfedge_iterator;
   typedef Ss::Halfedge_handle   Halfedge_handle;
   typedef Ss::Vertex_handle     Vertex_handle;

   typedef CGAL::Straight_skeleton_builder_traits_2<Kernel>      SsBuilderTraits;
   typedef CGAL::Straight_skeleton_builder_2<SsBuilderTraits,Ss> SsBuilder;

   SsBuilder ssb;

 

   for(int i=0;i++;i<27)
   {

       /* According to the boundary to generate the pts  */

       Point_2* pts=new Point_2[numPointsInPart];
       ssb.enter_contour(pts,pts+numPointsInPart-1);
   }

   ss=ssb.construct_skeleton();

 

  

--------------------------------------------------------------------------------------------------------

  The program so time-consuming that it needs about 27 hours to calculate the straight skeleton of this Polygon with holes.

  Could anyone help me ,why this algorithm is so time-consuming? Any suggestion is appreciated! Thanks in advance!

  

 

 

  Regards

                                                                                               TaoJia

 

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