Deluge and Transmission are good cross platform GTK apps.
Transmission uses Qt on Windows, either GTK or Qt on Linux, and something AppKit on macOS.
Transmission has Qt and Win32-native GUI clients as an alternative to its GTK client.
I don't think Transmission is a good example.
Re:Writing Gnome Apps with Swift
by sirwhinesalot on Wednesday March 27, 2024 @06:44PM
(#39845509)
Transmission only uses GTK on linux.
There is a Qt and CLI client, too.
Re:Writing Gnome Apps with Swift
by seabrookmx on Wednesday March 27, 2024 @11:11PM
(#39847369)
And a web UI! (My preferred method as I run it on my home server)
Evidentially it is possible to make GTK apps work at least somewhat nicely on Windows and Mac since there are a few out there. But it's clearly a ton of work. If you just make a standard GTK app it will be terrible. Most toolkits (e.g. Qt or even Flutter) work much nicer without having to fix them.
That said GTK on Windows and macOS is very meh. You don't choose GTK for making a cross platform app.