[sane-devel] Buttons, SANE2, scanbuttond, and other such rambling

[Charles Duffy]

While waiting for the USB issue impacting Fujitsu fi-4120C2s to be resolved, I'm
looking into the steps necessary to run a (scripted) scan of whatever documents
may be in the ADF when the "scan" button on the front panel is pressed.

I've noticed the "startbutton" property exposed by the Fujitsu scanner -- but
also that it's not available from any other driver. I've also found the
availability of scanbuttond (which *doesn't* presently support fujitsu
scanners), and the plans to eventually expose button state as a bitfield within
SANE2.

Regarding SANE2 -- is there any plan to allow a driver to expose a list of names
(ideally taken from standardized suggestions where possible) which map to
members of the button-state bitfield? This would allow the bitfield interface
(which is a good one) while also allowing buttons to be named by the backend
(which from what I've read appears to be a popular request).

Now, for the immediate case -- would 'yall suggest writing a SANE frontend that
polls the startbutton property and exits and launches scanadf when the button is
pressed, adding an option to scanadf to wait for startbutton to be true before
starting a scan, or extending startbuttond to know how to talk to Fujitsu's
scanners? Any of these seems to me to be a legitimate option, although the
scanadf option and SANE frontend would be Fujitsu-specific (as no other frontend
exposes that option), making it less likely for the scanadf patch to work its
way upstream.

(I've written a simple libusb-based driver before, so I shouldn't be
*completely* lost working on scanbuttond -- but it seems like such a shame to go
write a completely separate reimplementation of the button-querying code when
the SANE driver already has such support).

Thoughts?