Hyphenation patterns and adjusted kerning: ConTeXt vs. LuaTeX

["Heilmann, Till A." <till.heilmann@unibas.ch>]

Maybe the ConTeXt community can be of assistance to the LuaTeX bunch ...

As a new LuaTeX user, I came across the following problem: Using Lua(La)TeX, customized kerning of letter pairs (via the FeatureFile capability of fontspec) is ignored when it coincides with a possible hyphenation of a word (e.g. between 'f' and 'h' in German words like 'aufhalten'; see first minimal example below).

Ulrike Fischer was so kind to point out two things (http://tug.org/pipermail/luatex/2011-February/002569.html): First, the problem seems to be the break points between the adjusted kerning pairs. Second, ConTeXt seems to handle this case correctly (see second minimal example below; feature file bonum.fea from first example required).

I am no expert in neither LuaTeX nor context, but Ulrike suggested I post here and ask if the (typographically correct) ConTeXt behavior or solution can be reproduced with Lua(La)TeX.

Thanks,
- Till

1. Lua(La)TeX

\begin{filecontents*}{bonum.fea}
languagesystem DFLT dflt;
languagesystem latn dflt;
feature kern {
pos f h 100;
} kern;
\end{filecontents*}
\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage{fontspec}
\setmainfont[FeatureFile=bonum.fea]{TeX Gyre Bonum}
\begin{document}
fh aufhalten
\end{document}

2. ConTeXt

\mainlanguage	[de]
\definefontfeature[test][featurefile=bonum,kern=yes]
\definefont[test][name:texgyrebonum*test]
\starttext
\test fh aufhalten
\stoptext


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