[sane-devel] Seeking Odd-Page Vertical Flipping to Support ADF-Duplex

[Jeff Rush]

I'm working in the sane-epson2 backend, trying to get it to fully
support adf-duplex for scanning both sides of a page, for the Epson
ES-H-300 scanner.

I've just submitted a patch (#313667) to enable the duplexing.  It
works, and now I have a button on XSANE under Advanced Options.  However
the even (backside) page is 180-degrees rotated.

So as I'm looking thru the driver source, I thought I'd ask if there is
a standard configuration/setting in one of the internal data structures
I can use to cause every other page to be vertically flipped?

If not, I'm going to add to the epson2 driver some logic to invoke
sanei_magic_rotate() on the even-numbered pages, conditionally upon
whether the adf-duplex feature is enabled.  It seems this kind of logic
would be useful to others, and perhaps even already in the code someplace.

Suggestions or guidance welcome.

-Jeff