AVIF (AV1 Image File Format) support

[dllud]

AVIF seems to be gaining traction. It is now implemented on web-browsers (Chrome and Firefox) and image editors (GIMP, ImageMagick, Darktable).

Any chance sxiv can support it?

There are a couple of libraries implementing AVIF:

• libavif - The official one.
• libheif - The one used by ImageMagick

Using libheif would bring the added benefit of also supporting HEIF #430

[dllud]

I opened an issue at imlib2 bug tracker asking for AVIF support: https://phab.enlightenment.org/T8876
Meanwhile there's a basic loader that can be used: https://github.com/vi/imlib2-avif

[Strahinja]

I'd also like to see support for AVIF in sxiv, it's my main image viewer and AVIF seems to have much better compression, as well as support for transparency and animated images like GIF.