I don't think you can do that with a RIF, for the reason already
mentioned: Emacs is dumped in batch mode, where we have a frame type
that doesn't support fringes, and doesn't implement the RIF interfaces
you will need.

Ok, I'm not eager to rework this, so if you think that avoiding repeating that bit shuffling at the beginning is worth the additional coupling and complexity I trust in your criterion and close this issue. Thanks.