[XeTeX] Why 'Package xetex.def Warning: No clipping support in XeTeX yet'?

[Manuel Pégourié-Gonnard]

Hi,

While using graphicx with xelatex and trying to use the clip option, I got the
message:

Package xetex.def Warning: No clipping support in XeTeX yet

I googled a bit and found no real information, except that the question has be
asked on this very list a few month ago, with only one answer about "using the
xetex primitive", probably meaning \XeTeXpicfile or XeTeXpdffile. But
XeTeX-notes.pdf doesn't mention an option about clipping.

So I'm asking again: is it a limitation of XeTeX and/or the xdvipdfmx driver, or
is the file xetex.def (and the documentation) lagging behind? In any case, is it
planned to implement such a feature?

Thanks,
Manuel.

PS : reading xetex.def, I'm under the impression that clipping could work at
least for inclusion of PS files, through the use of a PS special. Am I right?