Death to px, long live ch | Hacker News Reader

Death to px, long live ch

shkspr.mobi

92 pointsBrajeshwar79 comments

I’ve found that ch and ex units are heavily influenced by latin characters. They just give weird results with non-latin characters leading to magic numbers. But the concept is really solid: use them if you want the spacing relative to text.

Nobody uses ch, let's be honest.

This is a problem whenever someone outside a culture tries to design for that culture. I have just enough knowledge of say, CJK+Arabic to read them, but not enough to know if the font/kerning/justification I'm using is attractive or ugly to natives.

It's often easy to spot Chinese goods because English writing on the stickers or manuals is in that horribly ugly latin serif font with bad kerning, which almost certainly looks fine if you don't read English all day.

The article links to

https://shkspr.mobi/blog/2018/11/the-myth-of-the-pixel-perfe...

which confuses me, because I definitely remember pixels being visible when I was growing up. I remember the first time I got a 1080p monitor. I felt a visceral terror at the fact that I could no longer see the pixels.

Yeah, you can see square-looking pixels on most screens if you display something with sharp aliasing. "There is no universal grid" is good to understand, but there are device-specific grids all over the place.

And all the examples that are ultra zoomed and/or showing antialiased font rendering obscure the pixels that are more visible in other situations.

That 0.01 to 0.04 degree range later in the article is big enough to drive a truck though. And you can see stairstepping at even finer distances.

Just to check: when were you growing up? In the CRT, it was often possible to see the physical pixels (i.e. the phosphors and the rows defined by the shadow mask), but there was not necessarily any guarantee that a logical pixel lined up with a physical pixel.

What I want to know is who decided to break px, the last thing we need is yet another screwball physical measurement, css was already full of them. But what "tut tut, everybody is using px and these new hi-dpi displays are rendering things really tiny, we can't have that" and now px as a useful unit is ruined.

Is there a way to use real pixels? My, admittedly quick, search says no. at least nothing jumps out at me from the spec.

px is still a useful unit. the user's operating system applying a scaling fator doesn't make it not useful.

if the user's operating system is configured to draw pixels at a 1:1 ratio, your pixels will be drawn at a 1:1 ratio. if the user's operating system is configured to draw pixels at a 2:1 or 3:1 ratio, you as a web developer don't get to override that, but you're still addressing pixels directly. if you want to write software that manages the user's hardware directly without giving them options to override it, the web is probably not the right platform for you.

No one decided to break it, it was 1/96th of an inch from the beginning.

The problem with different screens having different pixel densities was already present and obvious in 1996.

"Real" pixels are useless if you don't know anything about the screen you're going to render on.

I also did some experiment with ch many years ago. I found that 60ch is ideal width for block text for easy reading. too bad it is pretty hard to make websites with only 60ch wide.

I'm still waiting for operating systems to adopt true physical units. You know, that trick PostScript printers have doing since the 80s (running at 300dpi no less). I realize there are large screen projectors in the wild, that's solvable problem. Bitmaps icons are also an issue, but again, solvable.

Real physical units make sense when you're printing on paper.

I don't see how they make sense on screens. A one square inch image is fairly large on my phone, not too big on my desktop monitor, and pretty darn small on my tv. That's not to say that pixels make sense to use for layout at those scales either, but before everybody got into high dpi with scaling, it kind of worked... If you were comfortable with tiny text, you ran a higher resolution and if you needed things big, you ran a lower resolution.

> That's not to say that pixels make sense to use for layout at those scales either, but before everybody got into high dpi with scaling, it kind of worked... If you were comfortable with tiny text, you ran a higher resolution and if you needed things big, you ran a lower resolution.

And even with so-called "dpi" scaling, CSS pixels remain that except users have more options to also have their large TV display finer details.

Monitors these days provide metadata on their physical size. This laptop screen defines itself as 280x190 mm. Sure, that's not 1:1 with end user distance from screen, but it's a hell of a lot better than switching to mobile layout on my desktop based on how much I zoom my fonts and narrow the window.

What happened to em?

Just leave the viewport size up to the user rather than making assumptions about which widths work best for people you don't know.

Also despite the aggressive title, this article gives basically no reason for why you shouldn't use px.

Layout shift when the font loads

Not necessarily. See https://screenspan.net/fallback

There is no way I will abandon px.

In fact, I think CSS made the wrong decision by proliferating so many things, em, %, px, ch, whatever-else. The human brain is not well-equipped to have so many things for basically the same thing. That's a design flaw in CSS, plain and simple. And the author is thus also wrong. There won't be a mass movement of people using "ch". It would be a good first april article though.

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