[Gnome-print] Future Changes in Gnome Print.

[Miguel de Icaza <miguel helixcode com>]

Hello guys,

   I talked to Chema longishly about GnomePrint the other day as he is
writing various native drivers for GnomePrint, and we came up with a
design that we think is ok.

1. Printer Profiles.

   A printer profile will be an XML structure that will contain
   information about a specific printer that would enable gnome-print
   to print to it.

   For example:

	<printer>
	   <guid>947adab1-9fc1-4823-95a5-04a79146fa50</guid>
	   <vendor>Hewlett Packard</vendor>
	   <model>XXX</model>
	   <gnome-print-driver>PCL</gnome-print-driver>
	   <resolutions>
	      <resolution type="bw">150</resolution>
	      <resolution type="bw">300</resolution>
	      <resolution type="bw">Color600</resolution>
	      <resolution type="cmyk">300x600</resolution>
	   </resolutions>

	   <features driver="pcl">
	      something or other
	   </features>
	</printer>

   The "GUID" is a unique identifier, generated by the "uuidgen"
   program. 

   You can inhering most settings from a previous profile, for
   example:

	<printer inherit="947adab1-9fc1-4823-95a5-04a79146fa50">
	   <guid>c8a5029e-218c-433f-894d-80e3d0dab6dc</guid>
	   <model>YYY</model>
	   <resolutions>
	      <resolution type="bw">1200</resolution>
	   </resolutions>
	</printer>

    A printer queue would be then defined as:

	1. A spooling mechanism
	2. A guid identifier for a printer.
	3. A set of defaults to be applied to the printer.

    We can either keep the defaults in a separate file, or we can make
    the defaults part of the printer profile.  If we do make them part
    of the printer profile, then I suggest that when a setting is
    applied, we just do:

	<printer inherit="947adab1-9fc1-4823-95a5-04a79146fa50">
	   <guid>d60ccfad-244d-461d-842d-0132e59b9469</guid>
	   
	   <defaults>
	      <paper-size>a4</paper-size>
	      <ink-percentage>90</ink-percentage>
	      <resolution>150</resolution>
	   </defaults>
	</printer>

2. Installation of profiles

    We would ship a large file with all the profiles that we know
    about.  The user would select his kind of printer, and we would
    copy this profile to the system "Printer Profiles" directory.

    The user would be able to customize this printer profile, and when
    he does so, we just create a new profile with his default
    settings.

Comments?
Miguel.