[lltx] Kerning OTF fonts: 2 other problems

[Heilmann, Till A.]

Thanks to your help, I am making progress adjusting the kerning of  
OpenType fonts. There are still some problems, though ...

1. Curiously, adjusting the kerning does not work for some letter  
pairs and I cannot see a pattern here. Adjusting "ei", for example,  
works just fine but "ev" does not. I got the same results with two  
different fonts (TeX Gyre Bonum and Linux Libertine), so I think it  
is not a font issue but a Lua(La)TeX one.

2. Adjusting the kerning does not work in pairs where an unwanted  
German ligature (e.g. f l instead of fl) is prevented by the  
insertion of "| using babel. I suspect this is babel's fault but I  
wanted to let you know anyway.

Thanks,
- Till

\begin{filecontents*}{mykern.fea}
languagesystem DFLT dflt;
languagesystem latn dflt;
feature kern {
pos f l 500;
pos e [i g n m r s v w] 200;
} kern;
\end{filecontents*}
\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage{fontspec}
\setmainfont[Renderer=Basic,FeatureFile=mykern.fea]{TeX Gyre Bonum}
\begin{document}
fließt Auf"|lage ei eg en em er es ev ew
\end{document}