Re: Lilypond taking forever to typeset

[Mojca Miklavec]

On 13 July 2016 at 09:25, Werner LEMBERG wrote:
>> I wonder if fc-cache became more "nosy", trying to extract more data
>> from fonts than it did in the past or if it's just my perception (or
>> perhaps my computer became slower :).
>
> Probably the former.  Perhaps it helps if you try the latest
> fontconfig release, 2.12.0 – I think I saw something about speed
> improvements...

This is what I seem to have installed (and the one that took 2.5 - 3.5
minutes). I don't know which version is shipped with lilypond though.

(I would suspect that fc actually tries to iterate through all the
glyphs present in a font because it takes so long to process those CJK
font, and in particular the LastResort.ttf.)

>> - it really should print the warning before starting font database
>> generation (I was sure that my lilypond was broken and deleted it
>> earlier)
>
> Yes, this should be done.
>
>> - it could potentially only trigger font database generation when at
>> least one font change is requested
>
> Hmm.  Does lilypond really recreates the whole database instead of
> doing an incremental update?  I don't think so.  At least I don't
> experience such a behaviour on my GNU/Linux box.

The main problem is that lilypond needs those "2-10" minutes the first
time when it is being run. Which is exactly the critical moment when
the first-time users might give up.

On Linux you probably have a common fc database shared among all
software and you most likely generated the database already during the
initial linux installation (and probably many times after that). In
those cases the incremental database helps. For a Mac (and
perhaps/probably Windows?) Lilypond creates its own copy of the font
database. At the time of the first lilypond execution that database
doesn't exist and so the first lilypond run take minutes to complete
(it might be faster on those new super-fast computers with SSD etc.).

Mojca