Re: [Lib2geom-devel] lib2geom basics: define pathvector, define ellipse, define intersection

[mathog <ma...@ca...>]

On 02-Sep-2012 15:03, Krzysztof Kosiński wrote:

>> 2.  generate a third PathVector "pathC" = INTERSECTION(pathA,pathB).
>> Just like the Intersection option on the Paths menu.
>
> This cannot be done with 2Geom, because the boolean operations code
> does not work correctly. You need to use the old livarot library,
> which is undocumented and frankly nobody understands it. Your best 
> bet
> is copying what the Spray tool does: create an SP object containing 
> an
> ellipse and a second SP object (SPPath) containing your path, then
> intersecting them using the relevant function from sp-livarot.h.
>

splivarot.h functions all (or almost all) have

   SPDesktop *desktop

as a parameter.  That suggests  that they only operate directly on the 
drawing surface.
This is of course just a guess, based on the parameter name.  However, 
the Spray tool you refer to is interactive,
and it produces copies of objects on the drawing surface, and that is 
consistent with that guess.

Unfortunately that is not what I need to do.  The shape intersections 
are to go to a file and must
never be seen on the desktop.

Can livarot be used that way?

Thanks,

David Mathog
ma...@ca...
Manager, Sequence Analysis Facility, Biology Division, Caltech