[pjerem]

MacOS have always had the best font rendering on HiDPI screens and also the worst on Low-DPI.

Windows is historically very good on Low-DPI but they also managed to be great on HiDPI.

Linux, well, it depends on so much things … you can achieve good on both but you’d better be ok with integer scaling and not have multiple displays with different DPI.

[cehrlich]

Macs used to have good font rendering on Low-DPI displays (I would say the best, but I suppose that’s a matter of opinion)

Then Mojave switched to Metal and removed subpixel AA, and now it’s the worst.

Thread from when it happened: https://news.ycombinator.com/item?id=17476873

[kelnos]

It's funny to read that thread (from 6 years ago, wow time flies) and see complaints that a lot of people have low-dpi external displays. But I think some of the rebuttal comments in that article rang true even then, and certainly do now: if you are spending money on an Apple laptop or workstation, Apple is going to expect you to spend money on hi-dpi external monitors.

[necovek]

I'll reiterate a comment I made elsewhere in this thread. With my vision corrected, 4k at 24" (~190ppi) needs subpixel rendering for crisp fonts. I would expect 5k at 27" or 6k at 32" (both around ~215ppi) would be the same, so my only option for comfortable external use with a Mac is really 8k at 32". I know that I am an outlier as I get my vision corrected with glasses/contacts to better than 20/20 (outside that 5%-95% group I guess), but I was perfectly well served by subpixel rendering (and continue to be).

Luckily, Mac is only for work, and it is passable with 32" at 4k, but I can use Linux everywhere else for much nicer fonts. Unluckily, work is 8+h :)

[shiroiushi]

Sounds like you need to get a new job where you can use Linux. (For reference, I'm typing this at work, on a Linux laptop.)

[necovek]

Maybe :)

[nasretdinov]

Yeah, the issue is that 6 years ago your only option for a highdpi monitor with the correct scale (e.g. for 27'' it needs to be 5k, not 4k) would be the iMac or the XDR display that costs over $5k...

Now that Apple sells their own (very decent) monitor at somewhat more affordable price it makes sense to use it as an external display, I agree.

[lproven]

> MacOS have always had the best font rendering on HiDPI screens and also the worst on Low-DPI.

No it hasn't.

Maybe to you "always" means "since 2014" but if so that means you are very young and you should not generalise from that.

I've been using Macs since 1988 and Mac OS X since 2001 and it used to be great on SD screens. I used to use Safari on Windows XP because its font rendering was so much better than the built-in Windows Truetype renderer.

This change is new and recent.

It is absolutely not "always".

[orangeboats]

You can have displays with different DPI on Linux and achieve good font rendering. But it requires the latest versions of your favourite DE (like GNOME 45+ and KDE 6.x) and you'd need to give up X11 (which does not support mixed DPI very well).

[michaelmrose]

X11 handles mixed DPI fine. Monitor configuration GUI for DE don't support the required option however both X and nvidia-settings do

[orangeboats]

X11 quite literally doesn't have the notion of DPI, there is only a single coordinate space. Xrandr is per-output and not per-window.

[michaelmrose]

I'm literally sitting at a station with 3 monitors 2 high DPI and 1 low DPI wherein UI elements of a window moved from one monitor to the other are identically sized and this was the case when all 3 monitors were different sizes and DPI as well.

In this case the UI is scaled up by an integer factor on all screens so as to look nice on the highest DPI screen. It is scaled down from the higher resolution by a decimal factor that could be but needn't be an integer. If the factor is proportional to the difference in DPI the result is UI elements being sized precisely the same size across different size and dpi monitors.

All monitors share a singular scaling factor and DPI. Apps thus need to support high DPI but needn't do anything smart to support scaling because it happens outside of the apps remit.

This can be achieved again with xrandr --scale OR in the nvidia-settings GUI by setting viewport in to a higher resolution than viewport out. No the result isn't blurry.

[orangeboats]

First thing first, the X11 protocol is not aware of DPI. Period. And that has implications. You can apply all sorts of hackish solutions on top of it but (1) the solutions will most likely be out-of-band (not pure X11) and involve DBus/envvars/Xft.dpi, and (2) per-output.

Out-of-band solutions are effectively bandaids and they unnecessarily increase development difficulty of GUI programs on Linux, since developers now have to be aware of the various side channels (fragmentation!) that communicate the DPI scale.

This is why SDL2 for the longest period did not support HiDPI on X11, but does on Wayland, MacOS, and Windows. A COSMIC dev just recently made a complaint about XSettings too! [0] You can't just ignore those problems, "Linux is hard to develop for, blah blah fragmentation blah blah" I am sure you have heard of.

Another thing. Per-output HiDPI is fine when all your programs support high DPI, but it's unworkable if you want to mix LoDPI and HiDPI applications in a single screen, i.e. if an application has better user experience if it is upscaled and blurry (!), you are SOL unless you want to apply scaling to your entire desktop.

You also lose the opportunity to implement some neat features like temporarily scaling up a window if it is being magnified or screenshot. (The idea's been floating about in the KDE community)

Finally, we can argue for days, but the HiDPI page on Arch wiki already says a lot when a good 90% of the article is about acheiving good DPI scaling on X11 [1]. Even the Wayland sections have an XWayland subsection in them...

[0]: https://tech.lgbt/@drakulix/113029499719670970

[1]: https://wiki.archlinux.org/title/HiDPI#Xorg

[michaelmrose]

Scaling is a built in feature of X for over 20 years intended for this use case no bandaids of any sort or awareness by the applications of differing DPI.

From the perspective of apps there is only one DPI with all scaling down handled by X at a layer below the apps level. There really aren't any lodpi apps on a modern X system only Wayland has issues scaling X apps correctly. Gtk Apps not updated this decade can handle scaling up by integer factors and because X scales the lower dpi monitor down to the appropriate size the app doesn't need to handle anything else.

Its very odd for folks to argue that my mixed DPI system using only basic boring old xorg.conf somehow doesn't exist. I mean would you like to come to my apartment and open a few different apps?

Its in a way ironic that between pure X, pure Wayland, and Wayland + xwayland only the last can't handle mixed DPI.

[lostmsu]

Does it have anything to do with DPI? I thought basically the state is Windows rules, MacOS and Linux suck on non-integer scaling ratios. For integer nobody has problems AFAIK.

[michaelmrose]

X has supported scaling forever. Integer scale up everything scale down the lower DPI monitor or monitors.

xrandr --scale, xorg.conf, or nvidia-settings GUI and save to xorg config