Another area with a need to look closer into is fonts.
When playing around with the Firefox snap, I see that it uses NotoSansCJK-Regular.ttc for CJK scripts. I don’t find that file in the snaps, which indicates that /etc/apparmor.d/abstractions/fonts is in use.
Nevertheless, the symlinks in /etc/fonts/conf.d seem not to work as expected. It might be due to an ordering issue. I mean, the order in which the font configuration files are read by fontconfig is crucial — hence the prefix numbers in the file names. Can it possibly be that it’s configured to read /snap/gnome-3-*-*/current/etc/fonts/conf.d first, and /etc/fonts/conf.d only afterwards? In that case that may be one explanation why the system’s font config files are ignored to a large extent.
Edit:
In /snap/gnome-3-38-2004/76/etc/fonts/fonts.conf I see this section:
<!--
Load local system customization file
-->
<include ignore_missing="yes">conf.d</include>
Should an entry representing the system’s /etc/fonts/conf.d be added to or replace that entry?
Edit 2:
In an IRC discussion I was asked to provide a specific, reproducible example. Here it is:
-
Generate a Chinese locale:
sudo locale-gen zh_CN.UTF-8 -
Start firefox with that locale applied:
LC_CTYPE=zh_CN.UTF-8 firefox -
Go to https://zh.wikipedia.org
-
Use More tools -> Web Developer Tools to examine which fonts are used.
-
If firefox is a .deb, then you see “Fonts Used: Noto Sans CJK SC” as expected.
-
If firefox is a snap, then you see “Fonts Used: Noto Sans CJK JP” which means that some characters are rendered using the equivalent Japanese glyphs, which is not optimal and a regression for users with a Chinese locale.
-
-
In other words: The
/etc/fonts/conf.d/69-language-selector-zh-cn.conffile was not loaded by the snap.
The issue can be worked around temporarily by opening the file:
~/snap/firefox/current/.config/fontconfig/fonts.conf
for editing and adding this line:
<include ignore_missing="yes">/etc/fonts/conf.d</include>
And a more proper fix is on its way: