Allow wallpaper snaps to share images with the desktop

[Michael Hall]

Packaging wallpaper images into a snap is simple, but setting them as your desktop's background isn't as easy to do as it is with wallpaper images distributed in a deb. This is because the default background chooser lists images from /usr/share/backgrounds but not from /snap/<package>/current/.

It would be nice if a wallpaper snap package could have it's content automatically listed in the default background chooser, so that the user doesn't have to manually choose each one with a file chooser.

[Michael Hall (mhall119)]

One possible approach is to define a content-sharing plug in the 'core' snap for wallpapers, and then each wallpaper snap could provide a slot for it which, when auto-connected, will put that snap's wallpapers into /snap/core/current/usr/share/backgrounds/, and then include that directory in the default background chooser's list of default sources.

[Zygmunt Krynicki (zyga)]

I'm very interested in this topic and had extended discussions with jdstrand about how this could work in a safe way. This is not a priority for the snapd team currently but I'm personally interested in implementing this in the next few releases.