[Fontconfig] Pregenerate fontconfig cache

[Guillermo Rodriguez Garcia]

Hi all,

I have an embedded system where the list of fonts is known in advance
and cannot change. I want to pregenerate the fontconfig cache files
for an embedded system in order to avoid long startup times on first
boot.

I already learned that the cache files are architecture specific so
they need to be generated either on the target hardware or using qemu
or similar. What I am doing right now is:

- Install fonts on target system
- Generate cache files (fc-cache -f)
- Get generated cache files and add them to the build system
- Generate a rootfs image containing the original font files and the
cache files. This is the rootfs image that will be installed on the
target devices.

However when I install this rootfs image to the target system, on
first boot the pregenerated cache files are ignored, and the cache
files are regenerated again from scratch.

Setting FC_DEBUG=16 I see this:

$ fc-list
FC_DEBUG=16
FcCacheTimeValid dir "/usr/share/fonts/X11" cache checksum 1167623491
dir checksum 1167628683

Why are the checksums different? Is there a way to avoid this?

Thank you,

Guillermo Rodriguez Garcia
guille.rodriguez at gmail.com