Geometry Boost List: Re: [geometry] Strange behavior at difference algorithm

Subject: Re: [geometry] Strange behavior at difference algorithm
From: Adam Wulkiewicz (adam.wulkiewicz_at_[hidden])
Date: 2015-03-18 11:08:05

Hi Franz,

Franz Alt wrote:
> Hi Adam,
>
> I think I've found a little bug in my test program. My polygon type 
> using double types. With double polygon all results are fine. The 
> problems I've had was with polygons of integer types.
>
>   typedef 
> boost::geometry::model::polygon<boost::geometry::model::d2::point_xy<int> 
> > polygon;
>
> I've tested again on linux with gcc 4.8.1, gcc 4.9.2 and clang 3.5.0 
> with and without optimization (-O2) in c++11 and c++14 mode. With 
> polygons of integer type the outputs looking strange like in my 
> original mail.
>
> BTW: Thanks for your information about bg::wkt(..) and bg::svg_mapper(..).

I can reproduce the problem using int coordinate type.
This is not a bug in your program, the library should work with integral 
coordinate types. Though indeed switching e.g. to double could be a 
workaround.
I created a ticket: https://svn.boost.org/trac/boost/ticket/11121
Thanks for testing and the info about the problem!

Regards,
Adam