How to Change Fonts in Xastir
First: Consider using the "Text on Black" option in Xastir. It makes reading the fonts much easier. To change: Map -> Configure -> Station Text Style -> Text on Black. Feel free to try the other options there as well. It's possible that just making this change will alleviate the need to go through the below process, which is a bit tedious.
If you feel you still need to change the fonts, this is the procedure:
Install the "xfontsel" program. That's short for X Font Selector.
Ubuntu: "x11-utils" package SuSE: "xfontsel" package CentOS6: "xorg-x11-apps" package
Go to File -> Configure -> Fonts. You'll get a popup showing the different fonts. Make note of what's there just in case you want to get back. Maybe take a picture or a screenshot.
You can also find them in the ~/.xastir/config/xastir.cnf file. Here are mine:
MAPS_LABEL_FONT_TINY:-adobe-helvetica-medium-r-normal--14-*-*-*-*-*-iso8859-1 MAPS_LABEL_FONT_SMALL:-adobe-helvetica-medium-r-normal--14-*-*-*-*-*-iso8859-1 MAPS_LABEL_FONT_MEDIUM:-adobe-helvetica-bold-r-normal--12-*-*-*-*-*-iso8859-1 MAPS_LABEL_FONT_LARGE:-adobe-helvetica-medium-r-normal--24-*-*-*-*-*-iso8859-1 MAPS_LABEL_FONT_HUGE:-adobe-helvetica-medium-r-normal--24-*-*-*-*-*-iso8859-1 MAPS_LABEL_FONT_BORDER:-adobe-helvetica-medium-r-normal--14-*-*-*-*-*-iso8859-1 SYSTEM_FIXED_FONT:fixed STATION_FONT:fixed ATV_ID_FONT:-*-helvetica-*-*-*-*-*-240-*-*-*-*-*-*
Click on the "Xfontsel" button on the right of one you want to change. An xfontsel window should appear.
Change the font to something you like. A recommended method is to change to the original font first and then start messing with it one parameter at a time. You can certainly start from scratch with any font you like, but be prepared for some Xastir screens/dialogs to not look good/draw well with some selections, for instance overly large fonts.
Once you're happy, hit "select" and then "quit" in xfontsel2: The chosen font should get written back to the Xastir Fonts dialog.
Hit "OK" at the bottom of Xastir's Fonts dialog to save your new font changes.
Please change fonts one at a time using the above method and restart the whole process so you don't lose work somewhere in the middle. Note that you can directly edit the xastir.cnf file as well, but if you try that method, make a backup of it first and stop Xastir while you're editing the file.