Geometry Boost List: [ggl] Polygon difference

Subject: [ggl] Polygon difference
From: Barend Gehrels (barend.gehrels)
Date: 2011-01-10 12:37:47

hi Luke,

>> This is solved last December, but you have to use the "difference"
>> algorithm now. So reversing beforehand is not necessary anymore. So
>> difference and sym_difference now work for all combinations. There is
>> still an issue with self-tangencies, but in "normal" cases it should
>> always work.
> What is a self-tangency?  There are three types of self-touch configurations, edge touching edge, vertex touching edge and vertex touching vertex.  I'm guessing self-tangency is vertex touching edge.  Do you have a plan for how to solve it?
>
Good point. The issue occurs with multiple vertices touching one vertex. 
I did solve it for intersections and unions so for differences it will 
be similar, so that is the plan. Just need to have one or two days spare 
time for it.

Regards, Barend