CGAL users discussion list

["Antonino Mistretta" <>]

Hi Andreas,

in attachment is a jpeg with original polygon and skeleton nodes(in red).
This is the code that make this result:

        //! create cgal polygon by my polygon.
        Base::PolygonPtr _poly;
        _poly = Base::PolygonPtr( new Base::Polygon2D() );
        int startVertex = currPolygon->nVertices-2;
        int end = 0;
        for(int i=startVertex; i>=end; i--)
                (*_poly).push_back( Base::Point( currPolygon->padfX[i],
currPolygon->padfY[i]) );
        cgalPoly.push_back(_poly);

        //! make skeleton
        //! Insert vertex in skeleton_builder
        for( RegIt bit = cgalPoly.begin(), ebit = cgalPoly.end() ; bit !=
ebit ; ++ bit )
        {
                builder.enter_contour((*bit)->begin(),(*bit)->end());
        }
        //! build skeleton
        if ( !( skeleton = builder.construct_skeleton() ) )//!// Proceed only
if the skeleton was correctly constructed.
                throw string("Impossibile creare lo skeleton per questo 
poligono.");
        

        //!get skeleton points
        for (Base::Halfedge_iterator i = (*skeleton).halfedges_begin(); i !=
(*skeleton).halfedges_end(); ++ i )
        {
                //il punto fa parte dello skeleton??
                if (i->is_bisector())
                {
                        outX.push_back(i->vertex()->point().x());
                        outY.push_back(i->vertex()->point().y());
                }
        }

Why is_bisector() method returns not skeleton node?
I don't understant how I must do to use StraightSkeletonVertex class.

Thanks and excuse me to my english...

2008/4/4, Andreas Fabri 
<>:
> Hi Antonino,
>
>  Did you read the manual already. I think this is covered.
>
>  andreas
>
>
>
>  Antonino Mistretta wrote:
>
> > Can you show me a little example?
> > How I obtain StraightSkeletonVertex_2 object by Skeleton_Builder?
> > Thanks
> >
> > 2008/4/4, Fernando Cacciola
> <>:
> >
> > > 
> > >  wrote:
> > >
> > >
> > > > Hi All,
> > > >
> > > > I am using Straight Skeleton concept to find the skeleton polygon
> points.
> > > >
> > > > I call a construct_skeleton() method on istance of skeleton builder to
> > > > compute this(It's correct?).
> > > >
> > > >
> > > >
> > > Yes.
> > >
> > >
> > >
> > > > My question is - how can I get the coordinates of the skeleton vertex?
> > > >
> > > >
> > > >
> > > Using the 'point()' function as stated in the manual:
> > >
> > >
> http://www.cgal.org/Manual/3.3/doc_html/cgal_manual/Straight_skeleton_2_ref/Concept_StraightSkeletonVertex_2.html#Cross_link_anchor_783
> > >
> > > HTH
> > >
> > > Fernando Cacciola
> > > GeometryFactory
> > >
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> > >
> > >
> >
> >
> >
> >
>
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-- 
AM

Attachment: skeletonResult.jpg
Description: JPEG image