My experience with multiple monitors at different dpis hits nearly every case of failure he points out.
It's a lot more work to configure.
Apps fail to account for it.
Spanning two monitors results in terrible scaling problems.
Apps that do account for it at start up won't account for it during reposition, so they look fine if they open on the right monitor and terrible if moved to the other.
Getting solid workflows for flexible positioning requires hacks like mentioned at the end for xrandr.
Etc...
So sure, you can do it and it sucks.
That's not really the win I think the author seems to think it is.
I'm not even trying to defend X11, I don't have much love for it. I've done some Xlib programming in the past and I've hated it. I've never used Wayland, and I'm mostly on Windows these days.
But, I don't see how one could make a point that X11 is bad because of poor DPI support.
[1]: https://lobste.rs/s/ceylzx/forbidden_secrets_ancient_x11_sca...
Most of the comment is a rant about "X11 proponents". Can we please at least try to keep identity politics out of display servers?
Which fundamental issues does Wayland have with DPI? I'm not aware of there being any fundamental issues with the DPI handling there.
"If you think this idea is a bit stupid, shed a tear for the future of the display servers: this same mechanism is essentially how Wayland compositors —Wayland being the purported future replacement for X— cope with mixed-DPI setups."
encom•2h ago
My conclusion from running this and similar mixed DPI setups over many years is that mixed DPI is extremely poorly tested, if at all, by all vendors. KDE Plasma on Wayland finally pretty much gets it right 98% of the time. X11 wasn't a great experience, regardless of what's technically possible.
Windows has so many annoying issues. Apps are often blurry on the low DPI displays. The mouse cursor has no concept of screen DPI, and treats the entire working area as having the same DPI, so you have to hit the "exits" of the high DPI display just right to land on the low DPI ones. Positioning a window across different displays only scales it correctly on one. There's probably more, but I've been 100% Windows free for a couple of years now.
I wonder how OS X handles it. I don't like that OS, but it sounds like the kind of thing Apple would care about getting right.
looperhacks•2h ago
Low DPI screens are near unusable anyway on macOS without subpixel rendering
jojobas•2h ago
Take that, Apple haters.
the_mitsuhiko•2h ago
It absolutely is during dragging. macOS is perfectly capable of drawing a window on two screens at the same time, but it doesn't let a window cross two screens while resting which I think is a really good user experience choice.
zamadatix•2h ago
The cursor thing isn't really to do with DPI, it's a general thing with mixed reported display sizes regardless if they have the same DPI. I wish more systems had the option to cross borders at the relative position between monitors rather than the absolute but neither is necessarily more correct and I'm sure many prefer the absolute method.
doublerabbit•2h ago
I use FreeBSD as my daily driver and as well I use four screens, 2x4k and 2x1080p.
There are glitches and it's no near perfect but I would highly praise Xorg/X11. I've had no issues in a long time; maybe it's your distro.
jstimpfle•41m ago
Apart from automatic OS-level scaling applied as a post-processing step, which is almost guaranteed to look bad, this one is basically impossible to fix (from a technical standpoint). If you need to move "smoothly" between monitors, get identical monitors.