[Dev-luatex] Re: restrict pdfglyphtounicode to a tfm

Hi Ulrike, On Sun, 2025-04-13 at 12:15 +0200, Ulrike Fischer wrote:

And I didn't find yet examples or a documentation how to define a callback that "decorates" the tfm.

I think that this would be the "define_font" callback. You should be able to take the example from §6.3.3 and replace "v.commands = <...>" with "v.tounicode = { }" (the documentation says that this needs to be a UTF-16 string, but a table of integer codepoints works too). Luaotfload already hooks into the "define_font" callback, so you should only need to override "fonts.readers.tfm". Actually, there's already a function "fonts.mappings.addtounicode", so you could either replace that with your own function, or add a manipulator that runs before/after that. Thanks, -- Max