GTK front-end

Hello!

I'm working on a GTK front-end for mat2 (for now the code is in the wip branch).

My two main goals are:

• Making it easy to use;
• Making it work in a flatpak sandbox.

Here's some screenshots of what I have so far:

There's a few caveats in my implementation:

• Due to the sandboxing, I can only write files that the user has explicitly given me access to. So if I want to remove metadata in bulk, I can only replace the original files. I've added a warning dialog to make it clear to the user that its files will be overwritten. I have yet to decide if I add the ability to restore the original file, or if I move away from the bulk removal altogether and add for each file the ability to save in place or save in a new file (with a file chooser dialog).
• I haven't implemented the lightweight option (yet).
• I haven't checked the accessibility (yet).
• I haven't added a text somewhere explaining that some metadata may not be found (yet).

If you want to try it, you can clone the wip branch and install it with flatpak-builder:

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
flatpak-builder --install-deps-from=flathub --force-clean --user --install build-dir data/fr.romainvigier.MetadataCleaner.yaml
flatpak run fr.romainvigier.MetadataCleaner

It should also run fine as a regular program, but I haven't tested that yet.

Please let me know if you have any thoughts or comments!