How to open an image with a flatpak image viewer application using terminal commands?

Question

I'm using Ubuntu 21.10 and uninstalled the GNOME's default image viewer (eog). I installed the gThumb image viewer flatpak app instead.

What i want to achieve - What terminal commands should i use to open a particular image present in my pwd with the gThumb flatpak app?

What i tried - I found out that i could run the gThumb app using flatpak run org.gnome.gThumb but how do i append the image-file name in this command? I tried to pipe it with xargs but it didn't work.

I could open an image using eog <image name> earlier, how do i achieve something similar with the gThumb flatpak app?

Answer 1

You are trying to overcome unneeded problems. It is probably possible as with LibreOffice case with command like

flatpak run org.gnome.gThumb image-photo.png

But to keep it simpler - remove flatpak 3.12.0 version and install deb 3.11.2 version instead by using commands below

flatpak remove org.gnome.gThumb
sudo apt-get install gthumb

Answer 2

Flatpaks in general are run with a command

flatpak run <Application ID> <Arguments|Options>

You can see the Application ID in the output of

flatpak list --app

(the option --app will restrict the output to apps only, and not include runtimes)

So you can open a graphic file in eog with a command like:

flatpak run org.gnome.gThumb /path/to/graphic/file.png

For installed applications, wrapper scripts are provided in /var/lib/flatpak/exports/bin. This directory is not by default included in your PATH, but you could include it by appending a line

PATH="$PATH:/var/lib/flatpak/exports/bin"

to your ~/.profile. Then, you could run the flatpak of eog with the command

org.gnome.gThumb /path/to/graphic/file.png