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Subject: Re: [geda-user] Dead link in the wiki pages.
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Date: Mon, 19 Aug 2013 23:22:19 +0200
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On Mon, 2013-08-19 at 15:10 -0400, DJ Delorie wrote:
> > Indeed intersection of lines is a very simple problem, intersection of
> > line segments too, if you only need a boolean answer. If you need the
> > point of intersection it is a little bit more complicated.
> 
> You could just call intersection_of_linesegs() in pcb ;-)

Indeed I may consider that if I should need an intersection test of
multiple line segments -- I guess it is related to the sweep line
algorithm as described in

http://compgeom.cs.uiuc.edu/~jeffe/teaching/373/notes/x06-sweepline.pdf

But til now I was only interested in the much simpler intersection of
only two line segments (two tangents to a circle.)

I guess whenever I will consider intersection test of multiple arcs,
circles and line segments, I will have to look at the pcb code. But that
is only to verify the final routing result, which can be done by pcb
program itself. From my current understanding topological routing does
not need intersection tests for more than two elements each during
generation of the layout.