I noticed that certain glyphs are rendered incorrectly (probably due to wrong hinting) in GTK2/3 applications on Ubuntu 18.04.
For example, there is a vertical bar charcter
│ U+2502, that is used extensively to create solid vertical lines using just text characters.
You can see it in console apps such as
While it is rendered correctly in Terminal in both 16.04 and 18.04, when rendered inside GTK apps it has unexpected vertical gap in-between characters on 18.04 (16.04 renders it correctly).
The issue can be seen in GTK apps such as gVIM, Geany, GEdit, but Qt apps seem to render it properly.
I built a small GTK2 test app that reproduces the problem. You can find sources here here.
These are the results:
- Screenshot of this app running on clean Ubuntu 16.04. You can see line is solid.
- Screenshot of this app running on clean Ubuntu 18.04. You can see that rendering is incorrect and gaps are present.
Does anyone have any idea of why this happens? Should I report is as a bug in GTK or in Ubuntu? Any possible workarounds?