When getting the Unicode character map from the cmap table list, TTFunk only allows a value of 1 for "encoding_id" (which seems to equate to language code although I'm not sure).

According to Apple's spec for the cmap table the language code in Format 4 can be 0 for language independent fonts. This seems to be the case for Microsoft's symbol fonts (Webdings and Wingdings*).

So I think the unicode? method of subtable should allow encoding_id of 1 or 0. Currently symbol fonts' unicode character mapping can't be used. This is preventing me from outputting symbols to PDFs generated by Prawn, even though there's a Unicode mapping to the glyphs.

require 'ttfunk'
cmap = TTFunk::File.open("Webdings.ttf").cmap

cmap.tables[1].platform_id # => 3
cmap.tables[1].encoding_id # => 0
cmap.tables[1].format $ => 4
cmap.unicode # => []