[destructionator]

> So it seems like it actually modifies the drawing at the application level rather than rescaling it like an image.

X also supports exactly this. Qt uses this information. gtk doesn't for whatever reason, forcing the workarounds.

Most the so-called "X limitations" are actually just toolkit bugs if you get into the weeds.

[md8z]

GTK doesn't support it because nobody implemented it. IIRC the Qt support is also pretty buggy and doesn't work on some compositors.