[Scribus] font manager

[Craig Ringer]

Creolophus WC wrote:

>Hi,
>
>I would like to know, if there are any font managers, like Suitcase,
>in Linux (preferably free!)
>  
>
Not just the same, no. The font management capabilites are mostly on the 
level of the Windows Explorer font installation / Mac OS X font library.

>if not, is it difficult to write one?
>  
>
First, what do you really need this for?

Please consider that it's just less important to reduce the number of 
fonts loaded at any one time on Linux. For most applications fonts are 
scanned by fc-cache to generate a database of font information, which 
applications then load on start-up. This is extremely fast even with 
many thousands of fonts. In general, little or no memory is actually 
used by this until / unless a font is actually loaded and used by the 
application. Some apps that do their own font handling, like Scribus, 
may have longer startup times with many more fonts, but there's ongoing 
work to improve this. In my view, you'd be better off helping improve 
the font cache in Scribus rather than writing a font manager.

If your goal is to be able to add more fonts at runtime, I don't know if 
this is possible with most applications, as they initialize Fontconfig 
at load time (generally via the toolkit). You might be able to enhance 
toolkits to use inotify to watch .fonts.conf and re-scan, I guess, at 
least to add fonts. Removing fonts would be much harder. That goes for 
Scribus too, though in fact, Scribus can already add and remove fonts 
with no documents open. Teaching Scribus to be able to add new fonts 
with a document open probably wouldn't be too hard (if you're feeling 
handy with C++) but the innards will need a LOT of work before it'll be 
able to handle the _unloading_ of a font while a document is open. 
That's because Scribus doesn't currently know when a font is no longer 
in use.

It's worth noting that Linux systems have no significant limit on the 
number of fonts you can have available. There's little reason to use a 
Suitcase-style font manager in my view; at most I'd want a more 
convenient interface for adding new "temporary" fonts. That might be 
best done as a Scribus plugin. Don't expect most applications to be able 
to support this at all, except through toolkit modifications.

As for the difficulty of it, it depends on exactly what you want. If you 
want to maintain sets of fonts from different directories or maintain 
font groups that apps notice changes to when re-loaded, then no it's 
trivial - all you'd need to do is alter .fonts.conf .  Heck, it can 
probably be done with a tree of symlinks or hardlinks. Temporary fonts 
would be similarly trivial - a directory "Temporary" with symlinks to 
the fonts you currently want to load. If, however, you want to cause 
apps that are already running to re-scan their available font lists, 
you're in for some work, as outlined above. Get familiar with freetype, 
fontconfig, Qt, gtk+, and so on.

When it comes to Scribus, it's known that Scribus would benefit from 
better font unloading capabilities anyway, as this can be a major source 
of resource use growth, especially if someone is working with many large 
unicode fonts. I'm not aware of anyone making it a priority though, and 
I personally think there are any number of more important things.

If there's anything I haven't covered, please explain more clearly what 
problem you would be trying to solve, and what your goals are.

--
Craig Ringer