[dvipdfmx] xdvipdfmx/xdv2pdf "x:" specials

[Jonathan Kew]

On 02/09/2020 10:57, Joseph Wright wrote:
> Hello Jonathan (cc dvipdfmx list),
>
> There was a question on TeX-sx yesterday about the "x:" specials used 
> by XeTeX/xdvipdfmx 
> (https://tex.stackexchange.com/questions/560959/xelatex-graphics-specials). 
> I've tried to answer there, tracking stuff through, as today they are 
> also available in dvipdfmx. However, I wonder if they are or were ever 
> formally documented. I *think* you introduced them in xdv2pdf, but the 
> source repo for XeTeX/xdv2pdf only goes back to around 2006, and they 
> were already present.
>
> Is there anything you can point to about them?
>
> Regards,
>
> Joseph

Oh my, that's some ancient history!

There's at least a little bit of info, I believe, in the old "XeTeX 
Notes" file that represented the first "documentation" intended for 
anyone besides the initial author and target user of the system :) ... 
there seems to be a copy at 
http://www.tug.org/texmf-dist/doc/xetex/base/XeTeX-notes.pdf.

I'm afraid I don't have anything else readily to hand. Yes, these would 
have originated in xdv2pdf, which began as a somewhat ad hoc tool just 
to serve my immediate needs, before xetex really started to integrate 
into the wider *TeX world. I suspect I just started inventing 
\special{}s on the fly to meet whatever requirements I happened to have. 
(You have to recall that xetex was originally simply a tool created to 
serve my own specific use cases; if I needed to do something, I could 
modify any or all of my macros, the xetex engine, and/or the xdv2pdf 
driver in whatever way seemed convenient at the time.)

We would have been using Subversion at SIL back then, so that would be 
where the oldest source lived, but AFAIK that was decommissioned some 
years ago and I don't know what became of its history.

It might also be worth searching archives of the TeX on Mac OS X mailing 
list <https://email.esm.psu.edu/mailman/listinfo/macosx-tex>, which is 
probably where the earliest public discussions would have happened. A 
bit later, the XeTeX list at TUG 
<https://tug.org/mailman/listinfo/xetex> also got started, but IIRC that 
was once xetex started to gain some more visibility. I don't remember 
whether things like Ross's earliest xetex.def came before or after the 
dedicated XeTeX list was created, but it seems possible we may have 
corresponded about this stuff on one or other of the lists.

Good luck!

Jonathan