[Desktop_printing] Usability: Printing roles, tasks and environments

Michael Sweet mike at easysw.com
Thu Mar 9 05:24:07 PST 2006

Johannes Meixner wrote:
> ...
>> IMHO the failsafe way to go about it is to add printer setup helper plugins
>> that allow a driver to extend CUPS' capabilities of printer detection, PPD
>> selection, and printer capability detection.  Anything else is just wishful
>> thinking, IMHO.
> I fully agree regarding the last sentence.
> But I wonder how such a plugin could work.
> CUPS' printer detection is done by running all backends.
> Therefore all existing printer-specific detection plugins would have
> to be simultaneously plugged in into all those CUPS backends which
> match to a particular printer's connections (e.g. for a higher-level
> HP all-in-one device: parallel, usb, hp, lpd, ipp, socket).

This is something that can be prototyped in CUPS 1.2; backends now
support the back-channel link, so a program can, with the proper
permissions, run the backends to query the printer directly.  We
obviously don't recommend this for normal user apps, but for a
configuration application it would be appropriate.

Once we have enough experience for how things will work best, we
can add a new IPP request (CUPS-Get-Recommended-PPDs?) that puts
the query into the scheduler, probably via a helper app like
cups-deviced which will contain the core bits of the prototyping
work done for CUPS 1.2.

Right now, the CUPS-Get-Devices request will return the detected
model name and 1284 device ID for each device, and you can look
this info up via the CUPS-Get-PPDs request.  That is what the web
interface currently does, highlighting the "best" match (best
meaning the PPD that has a NickName closest to the reported make
and model for the device) and allowing the user to override the
selection.  Adding the device ID to the mix in on the TODO list,
but probably won't make it for 1.2.0.

Michael Sweet, Easy Software Products           mike at easysw dot com
Internet Printing and Publishing Software        http://www.easysw.com

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