Ancient X11 scaling technology

Drawing a circle is kind of cheating. The hard part of scaling is drawing UI elements like raster icons or 1px hairlines to look non-blurry.

And also doing it for multiple monitors with differing scales. Nobody claims X11 doesn't support different DPIs. The problems occur when you have monitors with differing pixel densities.

At the moment only Windows handles that use case perfectly, not even macOS. Wayland comes second if the optional fractional scaling is implemented by the toolkit and the compositor. I am skeptical of the Linux desktop ecosystem to do correct thing there though. Both server-side decorations and fractional scaling being optional (i.e. requires runtime opt-in from compositor and the toolkit) are missteps for a desktop protocol. Both missing features are directly attributable to GNOME and their chokehold of GTK and other core libraries.

I've found the opposite, that only macOS handles that perfectly.

Windows still breaks in several situations like different size and density monitors, but it's generally good enough.

Recent Gnome on Wayland does about as well as Windows.

Windows is the only platform that tries to do it "correctly" as per the internet peanut gallery.

And, of course, doing it "wrongly" as per what OS X and Gnome does works a lot better in practice.