[tex-live] dvipdfmx and PDF /Decode

[Joseph Wright]

Hello all,

I'm working on the graphics drivers for LaTeX and support for /Decode:
this was in pdftex.def until recently, and we are now looking at
documenting it across drivers.

Based on the approach in pdftex.def and support for /Interpolate in
dvipdfmx.def, I've tried something that boils down to

    \leavevmode
    \vskip300pt
    \special{pdf:image (example-image-a.png)}
    \vskip300pt
    \special{pdf:image (example-image-a.png) <</Decode [0 0.5]>>}
    \bye

This produces the expected PDF but yields the warning

    dvipdfmx:warning: Ignore invalid attribute dictionary.

As far as I can see the /Decode syntax is OK and matches that which
works without issue in direct PDF output mode (\pdfximage).

Anyone know if this is a dvipdfmx issue, if there is something wrong
with the /Decode syntax, etc.?

Joseph