[luatex] How to query fonts.handlers

[Ulrike Fischer]

Am Mon, 4 Feb 2019 15:00:12 +1300 schrieb Henri Menke:

> Dear list,
> 
> I am trying to access extra kerning that I have defined using
> fonts.handlers.otf.addfeature.  Even though I query the kerning from
> within a paragraph where the kerning is evidently applied I can't seem
> to get the value stored earlier, see the comment in the MWE.  What am I
> doing wrong?

Your value is in the ktest lookup, so you need to read this:

\input luaotfload.sty


\directlua{
     fonts.handlers.otf.addfeature {
         name = "ktest",
         type = "kern",
         data = {
             ["t"] = { ["e"] = 500 },
         }
     }
}

\font\1="file:lmroman10-regular.otf:mode=node;+ktest;" at 10pt
\1

test%
\directlua{
     local fnt = font.current()
     local tfmdata = font.getfont(fnt)
     local t = string.byte("t")
     local e = string.byte("e")
     local kern = fonts.handlers.otf.getkern(tfmdata,t,e,"ktest")
     local kern = kern / tfmdata.parameters.factor
     tex.sprint(kern) % 500 
   }
\bye


-- 
Ulrike Fischer 
https://www.troubleshooting-tex.de/