One of the rough edges of the linux/ubuntu HDPI experience is that that notify-osd scales weirdly and you get really bad anti-aliasing on fonts and images.
A brief google turned up Bug #1374301 “osd notifications blurry”, in which Steffen Coenen points out that starting notify-osd with the GDK_SCALE=1 enviromental variable fixes the problem.
I attempted to adjust this in the dbus services file like so:
sadly this didn’t work :(
Instead I wrote a bash script and changed the path in the service. pretty hacky but it works:
Seems to be working well, will update if I find issues.