[XeTeX] color directives in RL context

[François Charette]

Hello again,

Now another problem related to right-to-left typesetting which I had 
noted a while ago, this time probably a bug (or missing feature) in 
xdvipdfmx.

Suppose you insert the command \color{red} within a RL paragraph. The 
expected behavior would be that the text that follows would be in red. 
This is indeed what one obtains when typesetting with the Omega or Aleph 
engines and viewing the result either directly with xdvi or after 
conversion with dvipdfmx.

But with xetex+dvipdfmx (as well as with pdftex), the e-TeX directional 
directives are not taken into account, so instead of getting this: 
(where X represents text in black, R text in red and | the location of 
the color directive):

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
RRRRRRRRRRR|XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
   .RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR

one has rather:
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXX|RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR
   .RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR

My guess is that dvipdfmx (as well as xdvi) knows about Omega 
directional primitives, but that we still have to teach him and his 
brother xdvipdfmx more about the equivalent e-TeX directional primitives...

Perhaps someone can say whether this also happens with the Mac xdv2pdf 
driver?

Thanks in advance,

François