Re: [NTG-context] Hyphenation patterns and adjusted kerning: ConTeXt vs. LuaTeX

25 Feb 2011


      On 25-2-2011 1:18, Heilmann, Till A. wrote:
...
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}
I cannot test that (I only have the context minimals installed) but I 
don't know anything about latex internals so it would be a wild guess. 
Maybe babel is interfering?  In base mode kerning and and hyphenation 
happen in the traditional tex way, so there is not much extra trickery 
taking place.
...
2. ConTeXt
\mainlanguage	[de]
\definefontfeature[test][featurefile=bonum,kern=yes]
\definefont[test][name:texgyrebonum*test]
\starttext
\test fh aufhalten
\stoptext
Indeed I see a kern.

Hans

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