[tex-live] mvorigin option in (x)dvipdfmx

[David Carlisle]

A user question on stackexchange

http://tex.stackexchange.com/questions/355984/the-metapost-image-in-xelatex-is-offset

made me aware of a rather odd (but documented) issue with
xetex+xdvipdfmx image inclusion.

If metapost generated EPS are included, the bounding box offsets are
not propagated unless the mvorigin option is passed through to
xdvipdfmx.

This is presumably related to the fact that the files have negative
coordinates for the bounding box?  but why require an explicit option?
When would you not want to use that option?

The change is from last year just before we picked up support for the
xetex.def files on github


    * dvipdfmx.c, dvipdfmx.h, mpost.c: Introduce a new option --mvorigin.
    The translation of the origin in MP inclusion by using dvipdfmx.def
    or xdvipdfmx.def is enabled only if the option --mvorigin is set.




If the issue is just when the bounding box lower coordinates are
negative, xetex.def and dvipdfmx.def could detect that and shift the
image, but then of course the positioning would be wrong if the user
does use the mvorigin option, so I'm looking for any hints on what the
macro layer should do (and what the user-documentation should be)

David