CGAL users discussion list

["Sebastien Loriot (GeometryFactory)" <>]

On 11/08/2012 09:10 AM, Shriramana Sharma wrote:
> On Thu, Nov 8, 2012 at 1:19 PM, Efi 
> Fogel<>
>   wrote:
> > In all ways whatsoever.
>
> I'm sorry but I am not able to understand much from the above
> statement. Could you please show me an example of a predicate or an
> operation which would work correctly with "correctly" oriented
> polygons and not work with "incorrectly" oriented ones?
>
> Thank you for your patience,
You got the validity conditions here [1].

From [1], you can see that Polygon_2 as a method is_simple() and a 
orientation() method.

Polygon_with_holes_2 does not have a is_simple member function but
the global function is_simple can be used for outer boundary and holes [2].

Sebastien.

[0] 
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Boolean_set_operations_2/Chapter_main.html#Section_19.2
[1]http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Polygon_ref/Class_Polygon_2.html
[2] 
http://www.cgal.org/Manual/latest/doc_html/cgal_manual/Polygon_ref/Function_is_simple_2.html