When I use polish characters (ĄąĆćŁłÓóŃńŹźŻż) some are not shown in preview and in output pdf (substituted as # char).
With the update to FOP 2.1, I have finally figured out how to embed a custom font in the PDFs we generate. I've found some open fonts that have a license that's compatible with PCGen (cleared with ) that contain a lot of foreign characters. The first one I found was Google Open Sans (https://fonts.google.com/specimen/Open+Sans) but then I also found Google Noto Sans (https://fonts.google.com/specimen/Noto+Sans) which is a font family explicitly designed to reduce the so-called "tofu" (i.e. the boxes produced by missing glyphs), and I also thinks Noto Sans looks a bit better than Open Sans.
I'm attaching a version of the ĄąĆćŁłÓóŃńŹźŻż character PDF that I created with an updated OS using Noto Sans for your assessment.
Unfortunately Chinese or Japanese characters still are not available this way. While there are separate Noto Sans fonts that support those languages, I see no easy ways to be able to use multiple of these fonts to display the same text basically.
Submitted PR #1396.
I replaced the demo PDF for this change, the version I uploaded earlier was made with a previous commit and the grey temp boxes were broken. This is already fixed in the PR.
Most UTF-8 characters should now be supported by PCGen. Exceptions are far eastern languages for now.