Re: What I'm up to

   Cc: gimp-print-devel@xxxxxxxxxxxxxxxxxxxxx
   From: Roger Leigh <rleigh@xxxxxxxxxxxxxxxxxxxx>
   Date: Tue, 20 Jul 2004 18:56:05 +0100

   Robert L Krawitz <rlk@xxxxxxxxxxxx> writes:

   > Now, what I'm up to: I'm looking at printers.xml with an eye toward
   > the following:
   >
   > What I ultimately expect the file to look like is something like this:
   >
   >     <family name="escp2">
   >       <driver name="escp2-580" model="42">
   >         <parameter type="float" name="MagentaGamma" value="0.95"/>
   >         <parameter type="float" name="YellowGamma" value="0.9"/>
   >         <parameter type="float" name="Gamma" value="0.731"/>
   >         <parameter type="float" name="Density" value="1.0"/>
   >       </driver>
   >     </family>

   I would prefer

             <parameter type="float" name="Gamma">0.731</parameter>

OK.

   WRT the driver model number attribute, I would prefer (in the long
   term) if this could be removed, and the per-driver data in
   print-escp2-data could be moved here (is this the intent?).  This
   would require separate elements to specify the inksets, drop sizes
   etc., and should hopefully be usable by all family drivers (if the
   escp2_ types could be made more generic).

Certainly the model number should be removed, and the driver should
use the driver name to do the lookup.  Perhaps we can even do this for
5.0, since it shouldn't be too intrusive.  Moving all of the
per-driver data into printers.xml isn't what I have in mind, although
I'd certainly like to move the Epson stuff out of the code and into
data.

   > This can all be done without any API change at all, other than the
   > fact that there will no longer be a 1-1 mapping between printers and
   > drivers, so stp_get_printer_by_driver would have to return something
   > arbitrary, like perhaps the first printer encountered that uses a
   > particular driver.  However, it would be useful to allow applications
   > to get drivers as well as printers, so that e. g. test programs don't
   > have to keep a list of what drivers they've already seen.

   I'm not sure stp_get_printer_by_driver() is particularly useful
   now--what would a normal application need it for?  I guess the test
   program case is special, but surely they can just maintain a list of
   previously-seen drivers?

Yes, that's the other way to do it.  stp_get_printer_by_driver() is
actually used by all of the applications to get access to the
per-printer data.

   > We could choose to preserve compatibility by keeping all of the
   > stp_printer calls (which would essentially be shorthand) or not.

   When considering backward compatibility, what other applications
   (outside our source tree) are making use of libgimpprint directly?
   I only know of CinePaint.  If there's noone using them, we could
   remove them.

There are a couple of others; Roy Harrington's Quadtone RIP, and Bernd
Heller is also doing some kind of kiosk-like application.

   > What do people think about this?

   It sounds good.  One other thought:

   Currently, printers.xml is parsed once, but using
   stp_register_xml_preload().  This prevents installation of arbitrary
   third-party family drivers, since it would require manual editing of
   the file.  Perhaps it would be better to split the file into one file
   per family, which would be parsed by the family driver during its
   initialisation.  Even better (but less efficient) would be to have one
   directory per driver
   (e.g. /usr/local/share/gimp-print/VERSION/xml/driver/pcl/).  This
   would allow others to extend the driver without editing the installed
   files.

I don't know how far I want to go with this right now, since we want
to get this thing done, but this is a good thought.

-- 
Robert Krawitz                                     <rlk@xxxxxxxxxxxx>

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lpf@xxxxxxxxxxxx
Project lead for Gimp Print   --    http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton


-------------------------------------------------------
This SF.Net email is sponsored by BEA Weblogic Workshop
FREE Java Enterprise J2EE developer tools!
Get your free copy of BEA WebLogic Workshop 8.1 today.
http://ads.osdn.com/?ad_id=4721&alloc_id=10040&op=click