[XeTeX] The al-Wāḥid (al-W\=a\d hid) macron kerning problem

[ITS Mail]

Hello

I think I have a kerning problem with a Monotype Opentype font, Bembo 
Book MT Pro (let me know if you need to test it). In general I happily 
notice several kerning corrections in comparison with the previous 
Monotype Bembo, but when I want this:
\textit{al-Wāḥid}

the macron of the ā clashes into the W. I also get exactly the same 
clash in TextEdit.

Now, if I use the LaTeX input:
\textit{al-W\=aḥid}
there is no clash, but the macron is not a real one of course, rather 
too thin...

I have tried fontspec's kerning options with no success, and I have 
done this for the time being:
\textit{al-W{\kern -.4pt}āḥid}
but I wonder if a kind TeXnician can give real solution that is not so 
localised. I seem to remember the NFSS has something like declarations 
of pairs of characters whose kerning needs modification, or is this 
wishful remembering? I have many such Wā combinations in my document, 
so I would rather have something in the preamble to correct these pairs 
automatically.

Incidentally, is it worth letting the people at Monotype know about 
this kind of problem? Anyone with experience in this regard?

Thanks in advance!
Servus

Juan Acevedo
___________
Islamic Texts Society
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Cambridge CB2 8DQ
United Kingdom
Telephone +44 (0)1223 314 387
Fax +44 (0)1223 324 342
Website: www.its.org.uk
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