GTK 4

[Neil Hodgson]

   Fedora 34 was released recently and it includes GNOME 40 and GTK 4 4.2.0.

   A quick try to build with GTK 4 showed that there are many differences so porting to GTK 4 may take quite a bit of effort.

   To start, after installing the development package

sudo dnf install gtk4-devel

   replace the definition of GTK_VERSION in the makefile with

GTK_VERSION=gtk4

   then remove the inclusion of gdk/gdkwayland.h (which isn’t very important) in ScintillaGTK.cxx. That allows PlatGTK.cxx and ScintillaGTK.cxx to compile but it produces over 2000 lines of diagnostics.

   ScintillaGTKAccessible.cxx errors out on including gtk/gtk-a11y.h but removing that doesn’t help much as its the core header needed by this file. It appears that GTK has completely changed accessibility APIs for 4 with ATK listed on gtk.org as only for GTK 3.

https://docs.gtk.org/gtk4/section-accessibility.html

   Many of the classes used by Scintilla like GtkContainer have disappeared. Some areas like cursors appear easy to fix (there’s a different cursor creating function which takes a string instead of an ID) but missing classes would be more work. I don’t think that a gradual piecemeal approach to conversion will show success quickly and it looks like it would be more difficult to support GTK 4 within the same files as GTK 2 & 3 so it should be treated as a separate platform layer.

   Its unlikely I’ll have time this year to work on GTK 4 so it’d be great if someone took on this project.

https://docs.gtk.org/gtk4/migrating-3to4.html

   Neil