Re: [boost] [GGL][Polygon][Union] Union returns hole (inner ring) of the expected result as the output polygon (outer ring)

Subject: Re: [boost] [GGL][Polygon][Union] Union returns hole (inner ring) of the expected result as the output polygon (outer ring)
From: Barend Gehrels (barend_at_[hidden])
Date: 2010-01-29 14:12:57

Hi,

> Union of two polygon_2d returns a hole (inner ring) as result. Where -
>
> Input polygons -
> Polygon 1: A big rectangle with a hexagonal hole inside
> Polygon 2: A triangle that intersects the hole from inside leaving 
> portion of it in the hole
>
> Output polygon -
> The hexagonal hole without the triangle-portion.
>
> Expected output polygon -
> The big rectangle with current output polygon as hole (inner)as 
> described in this picture.
>
The exterior ring was omitted from the output. This happened earlier 
with Luke's test in November, it was solved provisionally then, but 
apparently this is the same problem. In the meantime the problem has 
been solved and I hope to deploy it this weekend to Boost sandbox, 
together with the multi-polygon union (w.r.t. Kef's message).

Regards, Barend