Cannot use GIMP Snap as RawTherapee external editor


Hi. I have the following set-up:

Kubuntu 18.04
RawTherapee 5.6 AppImage installed from their web site.
GIMP 2.10.12 installed via snap install gimp

RawTherapee will use GIMP by default as an external editor and it seems to transfer the file by saving it into /tmp and then asking GIMP to open it. GIMP launches OK but then complains it cannot find the file in /tmp. I assume this is due to the snap’s confinement.

is this something I can solve by modifying the GIMP snap connections or should I instead raise this as a bug with the RawTherapee team?

Thanks in advance


There is not interface that would restore view of regular /tmp from a snap’s point of view. This is a design decision that was taken long ago to isolate snaps from each other.

CC @pedronis for ideas if we want to change this.


The true solution, if I understand correctly, is for GIMP and RawTherapee to both be updated upstream to use the portals system for transferring files. This is dependant on the upstreams though.


Some time ago upstream developer stated that portal support is unlikely to happen even in gimp 3.


I was chatting with @kenvandine about this particular use case this week. It looks like we might be able to patch glib to automatically share documents via xdg-document-portal when using the g_app_info_launch or g_app_info_launch_uris APIs.

There is currently code in there to special case .desktop files marked as belonging to a Flatpak app:

We could do similar to detect snap applications based on the X-SnapInstanceName key. Provided the app plugs desktop this should work with no further changes on the app side. They could even use some non-GTK/Qt toolkit.