[Gnome-print] Re: [Gimp-print-devel] An introduction to gnome-print (fwd)

[Michael Sweet <mike easysw com>]

Sven Neumann wrote:
> ...
>         4. RGB rasterizer:  This is the most interesting part: this
>            driver can rasterize the printing commands sent to a
>            printing context and generate output as an RGB buffer for
>            the entire page (as an optimization, the RGB driver works
>            in 1-inch bands).
> 
>         5. A generic PCL driver (not yet fully plugged into the
>            system).   This PCL driver is just a "derived" class from
>            the RGB rasterizer.
> 
>            This driver contains a pretty neat set of compression
>            techniques to reduce the size of the file sent to the
>            printer.
> 
>      GNOME Print on top of that can send its output currently to a
>      file (or a device) or to a Unix printer spooler.

This is one issue that has come up before: aside from maybe providing
a basic driver for PCL printers, I don't think the right "solution"
is to embed drivers in the applications.  It doesn't scale, address
"corporate" issues like accounting, etc., and can lead to all sorts
of problems for new drivers, etc.  See more below...

> * Why I believe GNOME print is a better solution than GIMP print,
>   even for the GIMP.
> ...

I agree with all of these points; remember, however, that not all
systems use GNOME (gasp! :) and making GIMP print entirely dependent
on GNOME might limit its usefulness on other platforms.

> ...
>      You will notice that some of this overlaps with existing
>      projects, like the libppd-related things.  The reason is that
>      PPD is limited to Poscript printers, and we do need a solution
>      that can be applied to more than Poscript printers.

Actually, this is not the case.  PPDs can be used even with the
current LPR and Ghostscript printing solution, which solves issues
such as changing resolution and media size on a single print queue.

Also, CUPS (http://www.cups.org) uses PPD files successfully with
non-PostScript printer drivers; the PPD files are used by Ghostscript
and our image RIP to set driver-specific options which come through
in a header prior to the raster data for each page.

>      Our plan is to use libppd to "import" PPD files into GNOME print
>      profiles (check http://lists.helixcode.com, gnome-print archives
>      for the actual proposal).

I'd be careful about "importing" PPD file data into a different format.
In our experience it causes many problems (such as syncronizing and
updating to new drivers/PPDs), and you're better off sticking with the
original files.  Also, libppd (which is the CUPS PPD interface)
provides the data structures and information needed for applications
to format output for a particular printer and display options for the
user.

-- 
______________________________________________________________________
Michael Sweet, Easy Software Products                  mike@easysw.com
Printing Software for UNIX                       http://www.easysw.com