Q:

How to find the used characters in a subsetted font?

I have PDF files which are dynamically generated, with text, vectors, and subsetted fonts. I can see which fonts are used in various viewers - is there a way of displaying the actual subsetted characters of those fonts?
For example, I see the document contains the subsetted subsetted fonts "AAAAAC+FreeMono" and "AAAAAD+DejaVuSans". How do I find how many characters were subsetted from these fonts, and what characters they were?
(I tried loading the fonts in FontForge, but it just crashes while opening the file)

A:

The solution is to save the font data to a file and load it into a font editor. A subset font file is still a valid font file but it is possible that FontForge expects some data in the font that is not there. I have seen also many fonts that are not properly subset and this could also cause loading problems in a font editor.

