Re: gEDA-user: PCB+GL -> Stable (eventually...)

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Tue, 2010-11-23 at 23:37 +0000, Peter Clifton wrote:
> Hi geda-users, Kai-Martin,
> 
> Since I know some people have expressed an interest in why PCB+GL hasn't
> hit stable yet, I realised earlier that there was another step which is
> necessary... (besides cleaning up the hacks I made on top of the code I
> took from cairo).
> 
> The "polygon_speedup" branch on which the GL code sits might seem
> unrelated, but in fact there are changes in that branch which are relied
> upon when rendering polygons.
> 
> The "polygon_speedup" branch should mostly be a success, but I'm fairly
> sure it does increase CPU cycles for some operations. I've not had a
> chance to test it very scientifically, and I'm hesitant to push it to
> git HEAD without having at least made a few checks to see that it isn't
> penalising too many general cases.

Ok, so I've not done any significant benchmarking, but I've read through
the commits, attempted to convince myself I've not left any stupid debug
code, and written a few more detailed commit messages for the series.

There are a couple of commits I'm not as happy with left in my own
branch, but I've pushed the ones which are most solid.

I did have to almost completely re-write one commit, as I had lazily
used some rather convenient glib APIs in the core. I was very tempted
just to make configure.ac check for glib unconditionally and push!

So.. please fetch git HEAD PCB and play with things. It ought to be a
lot faster for boards with really complex polygons. For really simple
things it may have a slight impact due to extra processing overhead.

Please let me know if you find any cases with noticeable speed (OR ANY
BEHAVIOURAL) regressions. Obviously no speed regressions are desirable,
but as usual there are trade-offs involved. Gerber export "might" be
slower in some complex cases, for example.

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)
Tel: +44 (0)1223 748328 - (Shared lab phone, ask for me)



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