[derefr]

Question: running GTK apps in a Linux VM under Parallels in “coherence mode” provides a better user-experience (in several ways: smoother, better accessibility, etc.) than running a native-macOS-compiled GTK apps under XQuartz does. Why is this?

• Is it a difference of display model? Where/when compositing is done? Is X11 really that high-overhead of a protocol, that putting a “compositor in your compositor” like Parallels’ video driver does, can do better?

• Is it that macOS GTK apps are relying on macOS as the window manager / window decorator (which those apps were never heavily tested for), while “coherence mode” GTK apps are bringing their own DE (GNOME or what-have-you) along with them onto the macOS desktop, which “knows” what to do with those apps much better?

• Something else I’m not thinking of?

[asveikau]

I wouldn't discount the extent to which a Linux distro might tweak some config files and optional dependencies.

An example: when I started using freebsd on a laptop the fonts were pretty crappy relative to Linux. The code for Xorg, freetype etc. were identical in both places. I spent some time editing config files and it looked decent again. I assume my debian setup just had better defaults.