Re: [community-group] Remove REM/EM from specification? (#218)

Apologies for reviving this thread, and if there is a better place to move my comments, please let me know. 

I want to correct a few assumptions/declarations from this thread for the record:

1. A pixel is not an "absolute" unit of measure. As a point in fact, it's effectively a mathematical sample at the core, that has no space and dimensionality to it. When it is rendered onto a device, it then becomes absolute in the context of that device. So the size of a pixel on a phone screen is different than the size of a pixel in a VR headset. This is also true for color definitions, where "red" is different on different devices.
2. That a `pixel` became to be correlated to a typographic `point` was a happy accident of nature. I've spoken to the engineers on the original Mac and Mac OS about this. When they made the first Macintosh screens, it just so happened that the physical size of the screen lined up with a single pixel being 1/72 of an inch. Largely, this sort of mathematical happy accident occurs a lot in nature when dealing with a base/12 or base/8 type of math, especially in industrial design. If you look around today, a `pixel` no longer correlates at all with 1/72 of an inch, which is also why `dp` and `sp` exist.

When dealing with a spec of this nature, units should never be used with core definitions, otherwise you will run right into a wall of what a `pixel` or `point` is versus a `dp` or `sp` on mobile devices. Adding `rem` or `em` to that just doubles your headache, since those are systems built on top of whatever the lower level definition is.

Just treat the underlying math as pure math. Let the device, browser, or OS deal with the units. 

This is also true for color. I'd would strongly urge this group to remove gamut remapping, gamut definitions, color space translations, etc. from this endeavor. It will only serve to break the purpose of what tokens actually are.



-- 
GitHub Notification of comment by AndreiSeldon
Please view or discuss this issue at https://github.com/design-tokens/community-group/issues/218#issuecomment-2823884935 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config

Received on Wednesday, 23 April 2025 10:50:36 UTC