[XeTeX] Zero Width Non Joiner, or how not to make a ligature

[Gerrit Sangel]

Hello,

I just asked on the Unicode mailing list concerning encoding of Fraktur in 
Unicode. Because Fraktur sometimes does not use ligatures, it must have the 
the option to disable ligature between two characters. They told me I should 
include a Zero Width Non Joiner between the two characters.

I just tried this with XeTeX (although with the .otf Computer Modern files, 
because I don’t have a full featured Opentype Fraktur font), but this does 
not seem to work?

I just tried it this way:

fi – works fine, a fi ligature is produced

f[ZWNJ]i – does not work, Xelatex produces the following error:

“** WARNING ** No Unicode mapping available: GID=1, name=(none)”

It then just displays a 

f´i 

Is this maybe a missing feature of the font or does maybe XeTeX not support 
this?

I’ve loaded the font with 
\setromanfont{LMRoman10 Regular}
Should I add some options there?


I’ve included the source file and the pdf, I hope you can help me.

Thanks!

Gerrit Sangel
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