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	Fri, 13 Jan 2017 08:30:35 -0800 (PST)
Date:	Fri, 13 Jan 2017 17:30:30 +0100
From:	"Nicklas Karlsson (nicklas DOT karlsson17 AT gmail DOT com) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] made with gEDA --> layer transparency
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> > I need to come up with a strategy for upstreaming that.. basically, what
> > I did on my branch isn't super compatible with the newer PCB versions.
> > It extended the hacky way PCB uses extra layers in an arbitrary order
> > after the defined ones as silk layers (by adding two optional mask
> > layers after the silk ones).
> 
>   It would be great to get that upstreamed, and maybe even into pcb-rnd.
>  It looks like there's a huge amount of very good development happening
> on that project.  As soon as there's transparency support, I'll be on
> that like white on rice. :)
> 
> 
> Transparency support where, pcb-rnd?
> 
> Not sure when that might happen.. one of Igor's original stated reasons for
> forking was to rip out the (optional) upstream support for opengl which I
> added.
> 
> Sure, there are other ways to achieve transparency but they are likely to
> be slower than opengl.

I guess what is needed is a polygon library which could calculate and draw between a few drawing primitives: intersections, subtraction, addition. This library could also be used for clearance.

The same thing is actually done in CAD programs but usually in threee dimensions. There are boolean operations. Complex shapes are made from a few simple objects and material is removed by other objects.

The math and algorithms behind it is the hard problem but there are libraries avaialable for free.


Nicklas Karlsson

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