Unfortunately, there isn't a GUI configuration editor for you to use to deal with this problem under Ubuntu. The GUI font selectors under Gnome or Unity only allows you to select one font per option, while the Font Manager allows you to enable/disable fonts only.
But, as is the typical case of a Linux system, you actually can configure this, only you'll need to dig up the configuration option from lots of documentations.
Now, straight to the point: you'll need to edit/create the file ~/.fonts.conf.
- The file does not exist by default. However, if you've used things like Font Manager, then there might be a placeholder file at
~/.fonts.conf telling you to use ~/.config/font-manager/local.conf instead, in which case you should create the latter.
- You should first open
~/.fonts.conf to check.
- To check if the file exists, a simple way would be to open the file manager, go to "Home", check "View->Show Hidden Files" and see if you can find
.fonts.conf.
Once you've created the file, put the following code in it:
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<alias>
<family>sans-serif</family>
<prefer>
<family>Droid Sans</family>
<family>UKai</family>
</prefer>
</alias>
</fontconfig>
What it does is create a font resolution fallback list. When a program is requesting a sans-serif font (most GUI fonts are sans-serif by default), the system would try to use the first font (Droid Sans) for a character. If the font does not support that character, the second (UKai) will be used. I'm not sure if specifying Droid Sans as the first preference has any significance, but you might as well keep it, just to be safe.
Note also that you'll need to logout of your account and login again to see the effect.
For me, the effect is immediate after logging out and logging in again, and the font choice works system-wide.
The above answer is based on a related blog post: Fedora 中文字体设置
Edit
There is also a more comprehensive configuration sample under /etc/fonts/conf.avail or /etc/fonts/conf.d (I don't remember exactly which) whose name contains zh-CN. Inside is a set of configuration used for adjusting the exact fallback font order, which is far more suitable than the above method. Just copy the content in the file into ~/.fonts.conf or ~/.config/font-manager/local.conf and change the ordering of fonts to suit your needs.
In those two samples it looks like the font rendering algorithm is the same, one is just much darker than the other (and the darker one looks, to me, better).
This would be font smoothing "gamma" - gamma controlling how light/dark the partially lit pixels are adjusted.
Both the two following articles recommending setting font smoothing in Wine using regedit (yes, Wine maintains a Windows-style registry and has its own regedit.exe).
Run regedit.exe and adjust the following keys in [HKEY_CURRENT_USER\Control Panel\Desktop] to these values:
"FontSmoothing"="2"
"FontSmoothingType"=dword:00000002
"FontSmoothingGamma"=dword:00000578
"FontSmoothingOrientation"=dword:00000001
Articles:
Best Answer
There was a bug in the fontconfig package (I reported the bug, which has since been fixed in fonts-noto-cjk - 1:1.004+repack2-1~ubuntu1) which somehow let Chrome believe that "thin" is the correct weight to use. I removed the package and downloaded NotoSansCJK directly from Google, which contains fonts of different weights in separate files. After installing the fonts manually this issue seems to be fixed, and Chrome is able to render CJK correctly even though my default font is still unchanged (Liberation Sans).