[sane-devel] Interactive use of scanner buttons

[Kelly Price]

Allan hit it there.  You may have buttons that are exposed as USB
keyboard or HID devices, or it may piggyback on the protocol being
used for just scanning.  You may need a system notification app on
your desktop that integrates XSane (probably a localized saned over
Unix sockets).

That said... I cannot think of a scanner connected over the network
with saned will have any use for the buttons on the scanner itself.
The only useful button in that case would be "Copy" and only if you
attached a printer there... and in which case, the computer it's
attached to can handle a basic copy job by itself.  I can think of
extreme edge cases but that's it.  Hell, at my workplace we have
all-in-one copy/scan/fax network printers... and those things scanned
to a PDF and required an email address.

On Thu, Dec 2, 2021 at 8:43 PM m. allan noah <kitno455 at gmail.com> wrote:
>
> There is a great deal of variation between scanners and backends regarding what buttons are available and how they are exposed. You also have the exclusive device access problem. In the end, I think you need a new frontend, or modifications to an existing one, rather than a separate monitor.
>
> allan
>
> On Thu, Dec 2, 2021 at 5:35 PM Paul Wolneykien <manowar at altlinux.org> wrote:
>>
>>
>>   Hi!
>>
>>   As I can see, XSane doesn't poll the scanner's hardware buttons.
>> 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?
>>
>>   I've grep'ed the mailing list archives a little and it seems that the
>> main purpose of various button daemons (scanbuttond, scanbd) is to
>> implement such a facility as "push scan": the user goes to a remote
>> (possibly, network) scanner, places a standard material into it,
>> presses a button on the scanner and the system performes an automatic
>> (that's important!) scan.
>>   It also seems that in other situations, when a user wants to use an
>> interactive frontend (for making previews, selecting the scan
>> area, adjusting black and white points and gamma) the scanner is
>> expected to be placed on the table near PC. Or, at least, that the
>> material for scan can be placed into the scanner without a need for
>> further attention (i.e. a sheet material), so the user can set it up
>> and then back to his/her keyboard and mouse to make a scan or a number
>> of scans with different settings using the GUI frontend.
>>
>>   These two stories (the "push story" and the "desktop story") are nice
>> and simple, but are more or less unapplicable in the world of book
>> scanning!
>>
>>   Firstly, books are all different, so you need to make previews,
>> select areas and adjust things for each one. Secondly, books aren't
>> flat, so even if you use a special hardware you almost always need
>> to handle the book with both your hands!
>>
>>   So, for scanning books, it would be nice to be able to control such a
>> frontend as XSane with the scanner's hardware buttons. Because most of
>> the time you can reach the hardware button even if you handle the book
>> using both hands (however, a configurable delay after the button is
>> pressed may be helpful option).
>>
>>   (The other possible way to solve the described problem is to use a
>> separate triggering device. May be a pedal! But that's another story...)
>>
>>   I want to know/discuss, what a design of a button monitor for
>> use with interactive frontends would fit into SANE better. Any ideas?
>>
>
>
> --
> "well, I stand up next to a mountain- and I chop it down with the edge of my hand"



-- 
Kelly "STrRedWolf" Price
http://redwolf.ws