Before I go down the route of creating my own, I’m curious if anyone knows of a Ruler canvas. Something that works vertical and horizontal, and can go from inches, mm, pica’s, points, etc. Also want to show current cursor location.
I have one that I wrote as part of an MSPaint clone many years ago…
but it probably would need more work to bring it up to “standard” {retina etc) than it would to create one from scratch
It would be super easy to subclass a canvas… but I’m sure you are aware of that 
Hi bob, look at this post, don’t have picas, points and cursor (I can add it easily) but have scroll and scale, PM if you give a try and send you the source ;),