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Subject: Re: [geda-user] Apollon the technical thread
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On Tue, 22 Sep 2015, Larry Doolittle wrote:

> Roland -
>
> On Wed, Sep 23, 2015 at 12:51:28AM +0200, Roland Lutz wrote:
>> Rule of thumb, if something can go wrong, it will sooner or later go
>> wrong.  If you want to make sure the letters *never* accidentally
>> change, even not if someone in the distribution wants to be clever
>> and "fixes" something in the font without adjusting the version
>> number, then include the font in the layout file.  There's no easy
>> way around that.
>
> Sorry to beat a dead horse, but ...
> include the SHA-256 of the font in the layout file.

I am surprised noone mentioned the lib. What if the lib changes from 
system to system or from year to year? What if I had some text place 
carefully so that the edge of some letters in the middle didn't touch 
another object and then a different version of the library renders it a 
few pixels off?

Check libfreetype6: on a 32 bit x86; it's about 700k as a stripped 
binary. It's huge and it has a lot of code behing it: ~120k SLOC.
It's still under active development and has new versions from time to 
time.

It is very hard to believe that the rendering doesn't change. Bugs may get 
fixed, new features may affect old ones. I wouldn't dare depending on 
saving font info (even with extents) and then hope I can render the same 
thing ever again, not evenif I had the same font file.

Regads,

Igor2