Commit c847089 + this patch compiles and works mostly fine for me on Linux, GCC-10.3, GTK-3.24.

But I found 2 bugs: The credits view seems to miss the “interpret this as pango”-bit.

Image → Crop… does not work, I get this error message. Edit: With “does not work” I mean the crop-window does not show up.

** (viewnior:24376): WARNING **: 23:11:48.957: /usr/share/viewnior/vnr-crop-dialog.ui:12:37 Invalid property: GtkDialog.has_separator

Fixed those bugs along with broken dark background mode and some minor style issues.

Fixed bugs I had introduced with fullscreen and the crop rectangle.

I tested whatever else that I could think of, and it looks like everything works.

does not retain gtk2 compatibility

Why not? Would be good for backwards compatibility.

@orbea Backwards compatibility with what? Gtk2 is end of life and gtk3 has been available for over 10 years. Even xfce4's gtk3 port was finished over 3 years ago.

It's doable, and I've done that with older gtk3 ports like SpaceFM when gtk3 was still controversial, but unless there is a good example of where using gtk2 is preferable, or if Viewnior's maintainer requests gtk2 support, I don't see how keeping gtk2 compatibility would be more than a maintenance burden.

Seems to be an issue with the 'open image..' dialog, if selecting multiple images (ctrl+click) ...first image opens okay, but navigating to the second(and more) there's just : Fail to open file:<looks like recent clipboard history and/or random junk>:no such file or directory .
Then navigating back to the first image also fails.
Opening single image(ie the entire folder) is ok.
Open multiple images from a filemanager is ok.

Using arch, gtk3-3.24.30+62+g8d04980f38 and building from your fork..

@ncmprhnsbl This doesn't seem to be a gtk3 issue as I can reproduce the same with gtk2. It is probably a use-after-free issue. I'll see if I can resolve it regardless, but it would be best to open up a separate bug report to track that issue.

That's what it was. I'll make a pull request to fix it in the next few days, but for now here's a patch:

fix-use-after-free-multi-file.patch.txt

ah, yes, didn't think to check that.. issue #111 done..

I believe GTK+3 migration should be removed from TODO in this PR.

Glade files data/vnr-*-dialog.ui still use gtk+ 2.12. I suggest to update them to at least gtk+ 3.16 (labels on vnr-preferences-dialog.ui have xalign property which was introduced in 3.16) and fix deprecation warnings.

There is difference in fullscreen mode. Gtk2 has gray background, Gtk3 has black background. In window mode both versions have same gray background.
@BwackNinja Could you fix this difference?
Upd. Ristretto has same behavior: gray background in window mode changes to black background in fullscreen. Probably it's Gtk3 feature. Background color could depend on chosen Gtk theme.

Sure. I'll take a look. It should be simple.

Any news on this? Can I help in some way?