The game I'm talking about is O2Jam. It needs korean locale to show CJK characters. However, if launched with LC_ALL=ko_KR.UTF-8, the font becomes extremely small. Here's an example https://a.pomf.cat/rbubcz.png. If launched without korean locale, the font is perfectly fine: https://a.pomf.cat/baoqlh.png. I'm using the latest Wine version (7), but the problem has been there since version 4 if I remember correctly.
On old 2.X Wine version the fonts are way better and readable. Here's an example: https://a.pomf.cat/nicgrr.png
I tried to install CJK fonts with winetricks. I also tried to use korean fonts from Windows in the /windows/fonts folder, but the problem persists.
