Hey there! Since you're new to Linux, this weird font glitch can feel super frustrating—let's walk through the most likely fixes step by step.

1. Verify Your Locale Settings #

You mentioned running the locale command—let’s make sure the output checks out. If any LC_* variables (especially LC_ALL and LC_CTYPE) are set to a Greek locale like el_GR.UTF-8 when you don’t intend them to be, that can completely mess up font mapping across apps.

To fix this:

• Open a terminal and run:

  sudo dpkg-reconfigure locales
  

• In the pop-up menu, select your preferred UTF-8 locale (like en_US.UTF-8) using the spacebar, then set it as the default system locale when prompted.
• Reboot your system, then run locale again to confirm the settings are correct.

2. Check Xfce System Font Configuration #

Xfce’s default font settings might have accidentally picked a Greek font as the system default:

• Open Settings > Appearance and go to the Fonts tab.
• Make sure your default fonts (like "Default Font" and "Monospace Font") are set to a familiar, non-Greek font—DejaVu Sans or Ubuntu are safe, reliable choices.
• Double-check that font anti-aliasing is enabled (it should be on by default, but sometimes it gets toggled off accidentally).

3. Fix LibreOffice's Font Settings #

LibreOffice sometimes has its own font replacement rules that override system settings:

• Open LibreOffice Writer, go to Tools > Options > LibreOffice > Fonts.
• Look for the "Replace missing fonts" section. If you see a Greek font listed as a replacement for common fonts (like Arial or Times New Roman), remove that rule or swap it out for DejaVu Sans.
• If the issue sticks, you can try resetting LibreOffice’s user profile to default (just back up your custom settings first!).

4. Troubleshoot the PyQt5 App #

For your school project app, the problem could be in the code or Qt’s system integration:

• Check your PyQt5 code to see if you’ve hardcoded a specific font somewhere (like QFont("SomeGreekFont")). If so, replace it with a generic font name like "Sans" to let it inherit the system default.
• Alternatively, force the app to use system fonts by adding this line early in your code:

  from PyQt5.QtGui import QFont, QApplication
  QApplication.setFont(QFont("Sans"))
  

• You can also check Xfce’s Settings Editor (search for it in the app menu), navigate to qt4 or qt5 settings, and make sure the default font isn’t set to a Greek variant.

5. Clear Font Cache #

Corrupted font cache can cause odd rendering issues out of nowhere:

• Run these commands in terminal to clear and rebuild the cache:

  rm -rf ~/.cache/fontconfig/
  fc-cache -fv
  

• Restart your apps (or reboot) and see if the fonts look normal again.

Start with the locale check first—it’s the most common cause of this kind of font misbehavior. If that doesn’t work, work your way through the other steps. Good luck!

内容的提问来源于stack exchange，提问作者Joose Lindroos