In reply to @jthulhu:matrix.org
Hello, I'd like to install the avif pixbuf loader, but I'm very unsure on how to proceed. For starters, I'm not even sure if it's packaged; it could be in the libavif package, as its source code is hosted in the libavif repo, but some other distros package the two separatly, and I'm not sure how to check that by myself. Furthermore, setting this up seems to require more than just "installing the package", apparently Gdk needs some special handling for loaders to be taken into account.

In reply to @jtojnar:matrix.org
libavif package contains it. You can install it globally through the gdk-pixbuf NixOS module but that is an ugly globalism frail with many issues and will not affect apps that already have gdk-pixbuf loaders provided locally by a wrapper. The only reliable method is passing the loader to each app that requires it – see eog package for an example.

In reply to @jthulhu:matrix.org
If I understand correctly that code, all I need to do is to set services.xserver.gdk-pixbuf.modulePackages = [ libavif ];?

In reply to @jtojnar:matrix.org
That should be correct. But as mentioned, it won't work for some apps. Which ones did you try?

In reply to @jthulhu:matrix.org
I tried to see if nautilus was capable of rendering thumbnails of avif images. I've also written a very stupid Gtk application that only tries to load a file as a Gtk texture in Rust, just for the purpose of testing this (https://github.com/jthulhu/rki/tree/mwe). Yet, eog seems to work correctly, despite the fact that in the nix code that packages it, libavif doesn't seem to appear anywhere.