One of the main reasons we abandoned Pinta (https://github.com/PintaProject/Pinta) is we had to rewrite a significant portion of the app if we wanted to move to GTK3, as we had many custom UI needs.
See also:
GIMP, still on GTK2.
Inkscape released on GTK3 just within the past year or 2
One of the main reasons we abandoned Pinta (https://github.com/PintaProject/Pinta) is we had to rewrite a significant portion of the app if we wanted to move to GTK3, as we had many custom UI needs.
See also: GIMP, still on GTK2. Inkscape released on GTK3 just within the past year or 2