It may be useful for a compositor to crop and/or scale surface nodes, e.g. Sway needs to crop tiled toplevels.
@kennylevinsen has suggested adding some kind of "transformation node": the cropping would be configured on that node and would apply to all child nodes. Maybe other kinds of transformations would be useful too, e.g. wl_output_transform for rotation.
wlroots has migrated to gitlab.freedesktop.org. This issue has been moved to:
https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3276