Re: [hpoj-devel] Scan To

[Allen B. <ba...@lo...>]

"PASCHAL,DAVID (HP-Roseville,ex1)" wrote:
> Allen Barnett wrote:
> > Of course, I'd like to press the 'Scan To' button and see 'The GIMP'
> > appear on the LCD panel and then press 'START SCAN' and have The GIMP
> > start up (via ptal-mlcd?) and read the scanned image. Same for
> > 'StarOffice'.
> Actually, when you push "start scan", the peripheral only sends a small
> notification (a PML trap) to the PC indicating that a scan has been
> requested; it doesn't actually start the scan at this point.  Software on
> the PC has to register and listen for and handle this notification, which
> would consist of starting the desired application and starting the scan.

Hmm. Is listening for PML traps part of the current functionality of
ptal-mlcd? And does it already implement the registration of
applications for notification? (Ah, is this what ptal-pml is for?) [Hey,
I'm getting the hang of all these acronyms.]

> The problem with this scheme is that there are typically various scan
> options that need to be adjusted (color vs grayscale, resolution,
> contrast/brightness) before starting the scan, possibly on a trial&error
> basis.  An "automatic" scan doesn't give you this opportunity.

Practically, I think the most useful application of the ScanTo button is
if you have a number of similar items to scan and the OfficeJet is on
the other side of the office from the computer. Therefore, if a few
different settings of color/resolution/etc are common, you could make
multiple entries in the internal table like: SANE-300BW, SANE-600COLOR,
and so forth. The user daemon (as suggested below) could even download
these choices dynamically when it is started.

> > I think I understand, though, why this might be
> > problematic on a multiuser machine.
> The solution could consist of a daemon started by a user (possibly in a
> login or X-startup script) that would handle the notification and start the
> application, but I don't think it will be easy to tell the started
> application (i.e. GIMP or xsane) to also start a scan.  And if multiple
> users are logged in, then there could be problems if all users' scan-to
> daemons started the application, or if only a "primary" user could use it
> but a "secondary" user wanted to.
 
> > You might limit this functionality
> > to whomever
> > is logged on to X, though there might be cases where you'd
> > like to scan
> > to a batch job, too. Perhaps this is a job for a PAM module,
> > treat it as
> > though the scanner was logging in?
> Since scan-to was designed for a single-user Windows box, I think that makes
> it about as useful under Linux as the "Windows" keys on today's keyboards.
> Personally I think it would be much easier to just start the application
> first and then start the scan.  That has the added advantage of working on
> peripherals that don't have a "scan" button.  :-)

Well, my desktop machine is already nightmare of inappropriate /dev
permissions since I've never bothered to learn enough about PAM to fix
them properly. For example, anybody logged into the machine can sync my
Palm. Perhaps I should consider this an opportunity to learn something
new :-) [I'm thinking that PAM should adjust permissions on the
ptal-mlcd socket so that only the console user can connect. Or, if there
is a separate mechanism for registering interest in PML traps, adjusting
the permissions on that mechanism. Am I totally out in left-field?]

> Of course, just because the button says "scan" doesn't mean that it can't do
> something else instead in a Windows-free environment.  I suppose there are
> lots of possibilities here (remote shutdown/reboot or paging different users
> on a system come to mind, not that those are necessarily good ideas, of
> course).  The key would be to keep the solution as generic as possible.

Good, thinking 'outside the box'! Maybe you could use it as an Vorbis
jukebox :-)

What other functionality of the OfficeJet is available through PML? It
might be nice to set the speed dial buttons or dial the FAX phone number
directly. I take it that there is not extensive documentation on the
actual capabilities of these devices.

Allen