CGAL users discussion list

[Stefan Salewski <>]

On Fri, 2013-10-04 at 13:42 +0200, Andreas Fabri wrote:
> Have a look at the Apollonius Graph
> http://doc.cgal.org/latest/Apollonius_graph_2/index.html#Chapter_2D_Apollonius_Graphs
> 
> andreas
> 
> 
> On 04/10/2013 13:25, Stefan Salewski wrote:
> > I have a set of circles in 2d, they differ much in size and may partly
> > or fully overlap. I need to identify the ones which touch the convex
> > hull of the set, so that I can drop the inner ones.
> >

Thanks.

The Apollonius_Graph seems to be exactly what I need.
I have just copied together some code from
/usr/share/doc/cgal-4.2/demo/CGAL_ipelets/hull.cpp
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Apollonius_graph_2/Chapter_main.html#Subsection_45.5.1
http://stackoverflow.com/questions/18274584/cgal-2d-apollonius-diagram-for-weighted-voronoi-how-to-generate-and-get-the-fa

Seems to do what I want, I still have to write some bindings to Ruby
language. I need it for my experimental PCB router
(http://www.ssalewski.de/Router.html.en)

On Fri, 2013-10-04 at 11:29 -0700, jiju peethambaran wrote:
>The following paper could be useful to you. The paper describes an
>algorithm to determine the curves (or circles) in convex hull from a
>set of planar closed convex curves.
> Link----http://ed.iitm.ac.in/~raman/
> 
Also interesting, but more than I should need...