Sigh, yes another one of those "application X" has this feature posts.

Would it be possible to add units to the rules in Krita? That is say I am working on an A4 page doing a drawing that has real world measurements on it, and I want to use the ruler tool, to not only draw a straight line, but a line of say 5cm long. In CSP they have a ruler that looks a lot like a standard ruler you'd get at stationary store with mm and cm (or other as appropriate I am sure) and I can draw a "measured" line. Would be nice to have same in Krita as I do a fair bit of technical drawings (landscape plans etc) where it would help me to work "to scale"

Yes yes this is technical drawing and not painting, but I dare say it is not an un-useful feature for other users.