Gtk4 glass implementation will probably be a new glass implementation based on the current one because there are too many "breaking" changes.
Changes are listed here: https://docs.gtk.org/gtk4/migrating-3to4.html Specially note: https://docs.gtk.org/gtk4/migrating-3to4.html#adapt-to-gtkwindow-api-changes (*) https://docs.gtk.org/gtk4/migrating-3to4.html#stop-using-gtk_widget_set_app_paintable (*) https://docs.gtk.org/gtk4/migrating-3to4.html#stop-using-grabs https://docs.gtk.org/gtk4/migrating-3to4.html#stop-using-non-rgba-visuals https://docs.gtk.org/gtk4/migrating-3to4.html#switch-to-the-new-drag-and-drop-api * Gdk Surface would be used instead of Gtk Window. Backend (Wayland/X11) specific functions will be needed: https://docs.gtk.org/gtk4/migrating-3to4.html#adapt-to-monitor-api-changes https://docs.gtk.org/gdk4/wayland.html Looking at the Gdk4 implementation, using libwayland* directly would be nice, but simply too hard. So we could use Gtk4 to support wayland and #ifdef GDK_WINDOWING_X11 / GDK_WINDOWING_WAYLAND where necessary. On another note, XTest equivalent (for Robot) is not available on generic wayland compositors. -- Thiago.
