A couple of minor points

[fosero]

Apologies for not providing a patch, but a few points.

1. For rects I have to do it differently to make it work. For some reason your method just does not work for me, although it is seemingly the same thing.

Graphene.Rect().init(x1, y1, x2, y2)

2. In the RoundedRect section you mention that a radius of 360 makes a circle, as this is per one corner a radius of 90 makes for a circle.
3. See https://gitlab.gnome.org/GNOME/pygobject/-/merge_requests/196 for the Gdk.RGBA override being restored for GDK4. This allows for Gdk.RGBA(r, g, b, a) to work again. Also, for some more of these newer types overrides need to be added to make it cleaner to access them.

[Taiko2k]

Okay, I've applies changes for points 1 and 2.