[Dev-luatex] HarfBuzz [slightly off-topic]

[Graham Douglas]

Hi to all

Apologies in advance for the slightly off-topic nature of this
post. I've been reading about HarfBuzz which certainly looks to
be an interesting project. From the project page there is a link
to an article titled "State of Text Rendering" by Behdad Esfahbod

http://behdad.org/text/

Within that article is a section on TeX engines with a reference to
XeTeX and LuaTeX --- I'm just quoting a small bit of the article which
I hope is not too much out of context:

"The XeTeX creator is working on HarfBuzz on behalf of Mozilla now, and 
plans to port XeTeX to HarfBuzz eventually. In the long term though, 
pdfTeX's successor luaTeX should be made to do the same thing. There is 
more to Unicode support than just shaping, and in those areas the TeX 
engines can gain a lot by building on top of existing libraries."

At present my own understanding of the precise role that HarfBuzz could
play is a little sketch/hazy right now, but I'm working on that ;-). In 
the meantime I'd be interested to know if, in theory, HarfBuzz could be
usefully plugged into LuaTeX, such as via an external library 
(.so/.dll).From what I understand... HarfBuzz provides a shaping engine
so that, for example, it could provide useful services such as the bidi 
algorithm, and information that could be useful for typesetting complex
scripts such as Arabic. Again, I stress my currently incomplete 
understanding of the precise services HarfBuzz  would provide. lso,
how would you pass back to LuaTeX the results so that the LuaTeX engine
could use them?

If anyone could help me understand this a little more or indeed let me 
know if there really is nothing to explore that too would be good. I 
have not tried to compile HarfBuzz yet so have not played with it at 
all. I'm merely curious in light of the remarks on the HarfBuzz site.

Thank to anyone who can shed some light on this for me.

Cheers

Graham