[luatex] ligatures in OT truetype-fonts

[Florian Grammel]

Until now a XeLaTeX-user, I'm trying to get the hang of LuaLaTeX's font handling. Most things work perfectly fine, but LuaTeX's behaviour for some of my OpenType (TrueType) fonts is really puzzling me:

When I compile a simple example like

\documentclass{article}
\usepackage{fontspec}

\setmainfont%
[Ligatures=Common]% this should be superfluous, shouldn't it?
{somefont}

\begin{document}
fish fly 
\end{document}


I usually get the same result with LuaLaTeX as with XeLaTeX, i.e. when the font has a liga-feature, fi and fl are rendered as ligatures.

But using Didot.ttc or Baskerville.ttc (both vers 9.0d1e1 as installed my MacOS 10.9)
*only* XeTeX (3.1415926-2.5-0.9999.3) shows the ligatures, 
but LuaTeX (beta-0.76.0-2013061817 (rev 4627)) doesn't. 
Even stranger, Didot 6.1d4e1 from an older MacOS, probably 10.7, doesn't show ligatures on neither up-to-date engine, but *does* so, when compiled with LuaTeX beta-0.70.2-2012062819 as installed by TeXLive 2012 on the older machine.
Unfortunately I haven't been able to reproduce the error with a freely available font.

Does anybody know what is going on here?

Thanks in advance and best regards,
Florian.






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Florian Grammel

Gentofte, Denmark