[Gnome-print] Re: Importante.[Fwd: [printing-dev] intro / xprint server vs gnome print]

[Miguel de Icaza <miguel helixcode com>]

> One area I will have some responsibilty for is a
> Unix printing mechanism. I see there has been some
> talk about gnome printing on the list. I have very
> little knowledge about this (could somebody point
> me somewhere to get some info) so please bare with
> me. I was thinking up to this point that the X
> print server would be suitable candidate. 

There are a couple of white papers that describe what Gnome Print does
(references at the end).  The simplest way of describing GNOME print
is this:

	A C-based API that implements the Postscript imaging model.

There are two extensions to the Postscript imaging model supported by
GNOME print:

	Alpha channel support.
	Anti-aliasing.
	
GNOME print includes a rasterizing engine that transforms the
requests into bitmaps for native drivers . 

GNOME print is an actively developed project, and it is being used by
various GNOME applications. 

Various drivers are provided underneath this API, for instance, the
current version of GNOME print ships with:

	Postscript driver.
	PDF driver.
	On screen preview driver.
	Metafile driver.
		Used mostly for compound documents. 
	Generic bitmap driver 
		This is where "native" print drivers for WinPrinters
		and bitmap-based printers can be plugged in.
	Black and White HP PCL driver.

Gnome Print also offers other features for GNOME applications (iff you
want to use GNOME features):

	* A Gtk+ based printer dialog box that can be customized by
          apps.
	
	* A consisten print preview system that renders the commands
          sent previously.

The current limitations of Gnome Print are:

	* The lack of a ditherer between the rasterizing engine and
          the actual printer driver backend.

	  This means that only black and white show up correctly in
	  the output, incorporating a ditherer should be simple.

	* Lack of color management profiles.

The direction in which we want to move Gnome Print in the future
include:

	* Incorporation of a ditherer engine (maybe the one from IBM)

	* Incorporation of the 100+ native printer drivers from IBM.

At GNOME 2.0 time, the dependency on linking with Gtk+ will be gone,
as the base GtkObject object is moved into Glib (GObject).

I have been trying to get any kind of ditherer in place so we can
use something better than plain black and white in the HP PCL driver
(and other native drivers).

Miguel.