Add avif support to KDE

[est31]

The kimageformats library has support for AVIF since the release of KDE frameworks 5.78.0. Link to the commit that added AVIF support. The support is optional however, and requires the libavif library to be present. I imagine one needs to package libavif for nixos, then add it to the buildInputs/CXXFLAGS similarly to how it's done for openexr already.

[prusnak]

libavif is already packaged in pkgs/development/libraries/libavif. So maybe just adding libavif to buildInputs in pkgs/development/libraries/kde-frameworks/kimageformats.nix is enough?

@est31 Can you try if that works for you and if it did send a pull request?

[est31]

@prusnak interesting. I'll give it a try.

[est31]

So I've done some experimenting locally, and apparently if I only add libavif it still doesn't recognize avif files. It does create a kimg_avif.so file meaning that it successfully created a plugin, but when I try to open avif files using gwenview, it gives an error that it can't open application/octet-stream files. If I try to open an heif file however, it shows a different error: it complains that it can't open image/heif files. So maybe it has the module, but no clue it can use the module because it doesn't know the mime type.

Also, running xdg-mime query filetype returns the correct mime type for jpg and heif files, but does not return the correct mime type for avif files. I've checked and apparently the shared-mime-info package points to the 1.13.1 release from September 2019, but the patch to add avif was only merged in April 2020. The most recent release is 2.1 from Dec 31 2020. I suspect that an update of the shared-mime-info package should fix this, but need to test it. cc @mimame maintainer of shared-mime-info.

[est31]

I've looked a bit into the question of updating shared-mime-info. An update to 2.1 needed some adjustments to accommodate for the meson migration and a backport of a patch to not hit the internet during build. After that the package built but there was a test failure in one of the dependents... When I backported the AVIF patch for 1.13.1, I realized that basically everything depends on shared-mime-info. I eventually ran out of disk space during the build. I think that waiting for a regular update of shared-mime-info would be best.

[est31]

Also, it seems that the CXXFLAGS thing isn't needed.

[est31]

@prusnak I've tested the patch locally and it works (needed to wait until there were sufficient hydra cache results for #126050). I've made a PR: #127862

[datMaffin]

KImageFormat does currently not seem build:

See comments in PR of libavif upgrade: #128064

The following fix, which looks to be included in v5.83.0-rc1 seems relevant:
https://invent.kde.org/frameworks/kimageformats/-/commit/bf3f94da766d66a0470ab744dbe1ced4697b572d