[sane-devel] Scanner buttons (kind of RFC)

[Henning Meier-Geinitz]

Hi,

On Wed, Sep 11, 2002 at 12:16:13PM -0400, Matto Marjanovic wrote:
> Couldn't this be implemented as an ADF-like feature of a backend?

Probably yes. That's a good idea, at least until we have a better
solution.

> A backend for a scanner with a handy button could have a "multiple pages
>  via the button" mode.  In that mode, upon receiving sane_start() it waits
>  for the user to press the button before starting the scan.  Trivial!
> 
> Only problem is that I don't think there is any way in SANE1 for the backend
>  to specify that it has an ADF (real or virtual).  So this scheme would only
>  work for the scanadf frontend, which just assumes that an ADF is available.
>  (But, that's still extremely handy for scanning a lot of pages.)

XSane should be able to do this, too. The backend defines an option
"source" with values of e.g. "normal" and "wait for button". In XSane,
go to "setup"->enhancement and select the mode for automatic document
feeder (->"wait for button"). XSane then scans until it gets an error
condition.

The backend waits in sane_start for a button press. It could even use
a second button (if available) to stop the process (return no docs).

It's not perfect because XSane doesn't update its windows while the
backend waits in sane_start so you can't press the cancel button.

Bye,
  Henning