bug#25601: Possible need for an update to the \TeX "preview" package.

[Emmanuel Charpentier]

Dear AUCTeX maintainers,

at the suggestion of David Kastrup, I forward to you a suggestin 
initially sent to him, to which he answered he had no time nor energy to 
investigate :

I am a user of the knitr R package, which uses the preview package to 
create single-file images of R-generated figures. This package can 
generate tikz pictures, which are of great interest.

I recently stumbled on a  problem that is not specifically bound to 
preview, but shows that a (slight) revision may be in order. See the 
transcript of a thread in comp.text.tex at 
https://groups.google.com/forum/#!topic/comp.text.tex/umzerAdDkX0 .

Working on this problem, I saw that preview had an option specific to 
the XeLaTeX compiler. This made me think that an analogous solution was 
needed for the LuaTeX compiler, which uses the same mechanisms for font 
loading and font metrics. However, I do not know welle enough the 
internals of these engines to determine if the solution used for XeLaTeX 
can be applied to LuaTeX, of if specific actions are needed.

Do you think that a slight revision of your package could be done (if 
only to document how to use it with LuaLaTeX) ?

Sincerely yours,

                                        Emmanuel Charpentier