Change ruler units to PX

I just downloaded a trial version 8 (Mac), and I want to change Ruler units to pixels. Where do I do that?
(This is just the display UNITS, I am not talking about print.) Thanks!

I’ve always been under the impression they are pixels. Are they not?

Does not look like it; there is no way this is 100px.

Looks more like 50-60px.

What’s your resolution and pixel density of your display?

If you create a rectangle with a width of 100, then preview the prototype, it create an element with “width: 100px” applied. The ruler, and all measurements, certainly seem to be pixels.

You can even verify with the screen grabber tool on Mac to measure it.

OK, it looks like it is px, I just did a screen grab. You are right!