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

Oliver Rauch oliver.rauch@rauch-domain.de
Sat, 07 Sep 2002 00:27:52 +0200

Henning Meier-Geinitz schrieb:
> Hi,
> On Thu, Sep 05, 2002 at 02:27:33PM +0200, mh wrote:
> > would it be possible, to add an option called "button-state" to saneopts.h ?
> > "button-state" is an option of SANE_TYPE_INT with SANE_UNIT_NONE and
> > SANE_CONSTRAINT_NONE and capability SANE_CAP_SOFT_DETECT (i.e. a read-only
> > option).

> Other opinions?

The button protocoll should not be implemented this way.
The button protocoll has to be network safe. Imagine what happens
when 10 frontends poll the buttons at the same time and someone
does press a button, then up to 10 different people do scan
the document you want to scan.

We need a locking function that only one frontend is able to
ask for the button status.

I think it is important that we do not implement a quick and
dirty (and buggy) protocoll for the buttons in sane1.

I do not see a problem to add several new well know options
to sane1, but we should use the same options thaw will be used
in sane2 (if possible).


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