[sane-devel] Interactive use of scanner buttons

[Paul Wolneykien]

В Fri, 3 Dec 2021 17:07:47 +0100
Wilhelm Meier via sane-devel <sane-devel at alioth-lists.debian.net> пишет:

> On 03.12.21 16:54, Paul Wolneykien wrote:
> > В Fri, 3 Dec 2021 15:19:16 +0100
> > Wilhelm Meier via sane-devel <sane-devel at alioth-lists.debian.net>
> > пишет:
> > 
> >> There is this old project of mine called "scanbd", the "scanner
> >> button daemon". There wasn't low / no activity in the last
> >> year(s), but it is still functional because it is strictly POSIX
> >> conform.
> > 
> >   I've seen it. And I have a question about it:
> > 
> >>> And if I understand the scanbd manual right, the daemon locks the
> >>> SANE interface to the scanner until a button is pressed, and then
> >>> gives exclusive access to the scanner for the frontend. So, the
> >>> daemon is primarily for launching a frontend, but not for
> >>> controlling the frontend while it is running. Am I right?
> > 
> >   Is that true that the daemon isn't functional while a frontend is
> > using the scanner?
> 
> Which daemon do you mean?
> 
> If no scanning is active, that is no scan-application has connected to
> the scanbd-daemon, this daemon is polling the button.
> If an application connects, the scanbd starts saned to handle to
> connection. When the application ist scanning, no button-polling can
> be done (because scanbd releases the device so thant saned can grab
> the device). After the scanning the application disconects and scanbd
> starts polling again.

  Thanks. That use of scanner buttons I call "non interactive".
What I'm trying to find is a way to interact with a running GUI
frontend (XSane for example) using the scanner buttons.