Actually Linux has my favorite display scaling --- if you just have one screen.

I spend all day with Firefox, terminals, and emacs in XMonad and they all scale perfectly with no raster UI elements. (XMonad's pixel boarder I didn't bother to scale.)

On Windows and MacOS last I checked, there was a lot more resized raster bullshit.

Even with multiple displays it's not that difficult - just pass the scale you want for a given display when calling `xrandr` and things generally just work as long as you're downscaling from the "native" dpi you have X using.

It's 2020, we can make rockets land on self-driven barges, and somehow we're still forced to use xrandr manually...? This is the sort of thing that keeps me from going back to the Linux desktop.

You don't have to. Ubuntu 20.04 and Gnome desktop provide a fine hidpi experience. There are a few warts, but it all generally works. If you start dabbling with other desktop environments like xmonad or i3, it gets tricky.

I can never get it to work properly with multiple displays. I have a 4k monitor and two 1080p monitors. Using 192dpi with 2x scale (param passing to xrandr), all kind of display errors popup (wrong color, weird fonts etc).

Yeah, I wanted to configure hidpi on linux recently, when I had to work on FHD 14" screen without external monitor for a while. I found no config options in UI, and guides involving xrandr and fifteen different steps on the internet. I thought hell no and abandoned that idea altogether, cranked font size in the terminal and worked like that. And I actually "can" work in Linux and configure easier stuff. As far as I'm concerned at least some distros/DEs have non-existent hidpi support right now.

My configuration panel only has 2 options for scaling: 100% or 200%. Needless to say neither option is very helpful.

If in Gnome, fractional scaling is possible but not enabled by default. I use 125% and it has been fine. I did it via Gnome-tweak, or you can manually enable it [1].

[1] https://www.linuxuprising.com/2019/04/how-to-enable-hidpi-fr...

There should be a slightly hidden custom option if you're using windows. (Not in the drop-down)

You'll have to relog for the scaling to take effect with custom numbers for some reason

You can only do integer scales though this way, can’t you?

As for me: I haven't figured it out yet, sometimes a fractional scale works, sometimes you get vague errors. In any case what I have noticed is that quality drops significantly if you use fractionals.

For my set-up at home (1080 - 4k - 1080) I have a simple script, that really was more of a `write once - use always`-experience. E.g.

    xrandr --output HDMI1 --auto --scale 2x2 --pos 0x0+0+0
    xrandr --output eDP1 --auto --scale 2x2 --pos 7680x0+0+0
    xrandr --output DP1 --auto --mode 3840x2160 --scale 1x1 --pos 3840x0+0+0 --primary

So basically what I do is, I virtually up-scale my other screens up to 4k, such that system-wide zoom settings are (more or less) consistent and enjoyable.

No, with `xrandr` you can scale to any fractional amount. For example, I had 2 24" external monitors (full-hd, not 4k), and a 13" thinkpad (chromebook, booted into linux). Obviously, the respective DPI's were way off.

Just a quick calculation in a repl, then called xrandr with the right scaling number, and presto, I had them exactly the same.

Then, with precise lining up of the displays, it was basically one seamless "sheet of paper". If I had a long web page or pdf spanning the displays (the laptop was directly under the monitors), then scrolling through it was quite "trippy".

I think because this was now a unified display where the bottom 1/3 was tilted differently to the top 2/3'rds (think of a curved ultrawide, but in portrait mode)

Honestly, it really was that simple.

If you want fractional scaling I’d suggest you look into wayland.

How do you use xrandr in Wayland?

You don't want to. Wayland-based GTK and Qt should to do per device DPI. XRandR cannot.

Pop!_OS (their own Linux distro) has DPI scaling built in. I can actually turn on x2 scaling, and while it's huge on the poor 1080 display, it works perfectly.

Also a lot of the big linux distro's now have support for this. I know Manjaro and Ubuntu can do it with minimal effort.

Is there any end in sight for the pixel doubling hacks? Why do we even use them any more? Apps should have had plenty time to adapt to higher DPI displays by now, and X11 has supported per display DPI since the 90s and a scale factor on top of this seems obviously wrong.

And for the niche case where you have a big disparity in DPIs of multiple displays + apps that can't adapt to DPI on the fly, scaling up is surely the wrong solution, you should be scaling down no the smaller screen.

I've tried looking a bit into this at one point and my understanding is that it's more a toolkit issue than an app issue.

QT has an option to adapt the size of the widgets according to the reported screen resolution, which seems to kind of work. I don't use that many QT apps, so not sure how this turns out in practice.

However, GTK just doesn't care.

All this is on X11, I hear the situation is somewhat better on Wayland.

I'd guess in Wayland the compositor would be responsible for handling such issues.

I could readily see different filter profiles for different applications. Some of which render, and take input ques, at scaled resolutions.

What I hate a LOT more are games and applications that make any sort of connection between Pixel Aspect Ratio and a display resolution.

I recently got a 2020 Mac mini and I can tell you without hesitation: Linux+Wayland has far superior scaling support than macOS.

macOS only allowed me to run my 3440x1440 display at lower resolutions, but no _actual_ scaling support. The font is around 3mm tall.

Meanwhile, wayland scaling work wonders. The big issue being that xorg-only apps are blurry (it’s recently been fixed in master though).

I use Fedora on a 4K 15" display with an Intel GPU, and the scaling works fine. However, the Intel GPU is a tad underpowered for the task.

I use a Skylake on a 4K laptop with a 4K external monitor above it. It is plenty fast, with no tearing. Under Qubes, where app VMs don't get to use the GPU, mpv plays full-screen 1080p video using 3 cores.

(Oddly, the external monitor will do 4K only at 30 Hz. I don't know if that is a limitation of the laptop or of the monitor.)

The 30hz thing might be because of an older hdmi version, like 1.4. I have had the same issues and it was a hardware limitation

I have a 13" HP Spectre from mid-2017 with a 4k display. It's noticeably sharper (and brighter) than the 1080p alternatives. Prior to that, I had a QHD laptop from circa 2013. No font size issues on Linux that affected my work.

Ubuntu Unity, which I still use today, has working fractional scaling (in 12.5% steps) for ages now. In fact, I'm pretty sure it had that before even Windows did. Gnome seems to have finally caught up as well, even with Nvidia drivers. Like it or not, 4K is the current standard and going backwards makes no sense.