[Desktop_printing] PPD settings vs IPP options

[Robert L Krawitz]

   Date: Tue, 14 Feb 2006 13:29:59 +0100 (CET)
   From: Johannes Meixner <jsmeix at suse.de>

   On Feb 14 07:26 Robert L Krawitz wrote (shortened):
   > A related problem is when the printer itself offers two (or more)
   > choices of margins.  A lot of Epson printers, for example, offer two
   > choices of margins, normal and expanded (i. e. full bleed), and
   > representing this in a PPD file is problematic.

   Could you give some background info why it is problematic?

The PPD file only provides one imageable area per paper size.
Depending upon whether the full bleed option is set or not, the actual
imageable area will differ.  If the full bleed option is set, the
output size (and usually aspect ratio) will not match what the user
expects.

Consider the case of an A4 page.  Normal margins on a typical printer
might be 3 mm on the sides and bottom and 0 on top.  In full bleed
mode, the margins on the sides are about -3 mm and on the bottom -1 cm
or so.

Since everything is mediated through the PPD file (there's no
interactive/programmatic response to the choice of options), the
application doesn't know that the actual page size is different from
what it expects from the PPD file.

I suppose that one way around this would be to duplicate each paper
size in the PPD file (or more than duplicate if more than two margin
sizes are available on the printer), but that would be unmanageable as
the number of page sizes offered is already very large.

(I have other issues with PPD files also -- no way to represent curves
and other more exotic data types.  I'd like to be able to offer full
RIP functionality to CUPS users as well as users of Gutenprint-enabled
applications such as the Print plugin for the GIMP.  But that's
another matter.)

-- 
Robert Krawitz                                     <rlk at alum.mit.edu>

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

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