[Printing-architecture] Work plan for the new OpenPrinting CUPS filter package
Till Kamppeter
till.kamppeter at gmail.com
Thu Nov 10 22:20:18 UTC 2011
1. CUPS upstream drops the following filters and backends which are not
used by Mac OS X and passes them over to OpenPrinting:
Filters:
bannertops
commandtoescpx
commandtopclx
imagetops
imagetoraster
pdftops
rastertoescpx
rastertopclx
texttops
Backends:
serial
parallel
2. CUPS upstream removes all image-related functions from libcupsimage,
separating them in the temporary libcupslegacy (to be renamed/eliminated
by OpenPrinting).
3. All this with a correctly working build system is now downloadable
from CUPS SVN via
svn co http://svn.easysw.com/public/cups/branches/legacy-1.6 legacy-1.6
This repository will be converted/imported to BZR and uploaded as a new
package into the OpenPrinting BZR repositories as soon as the BZR repos
of the LF are back.
4. The current CUPS PDF filter add-on
http://www.openprinting.org/download/printing/pdf-printing/pdf-filters.tar.gz
plus the files
http://www.openprinting.org/download/printing/pdf-printing/cpdftocps
http://www.openprinting.org/download/printing/pdf-printing/cpdftocps.convs
http://www.openprinting.org/download/printing/pdf-printing/pstopdf
http://www.openprinting.org/download/printing/pdf-printing/pstopdf.convs
http://www.openprinting.org/download/printing/pdf-printing/pstopdf.types
will be added to the new CUPS filters package at OpenPrinting.
5. The functionality of accepting image files as print jobs will get
discontinued, removing the imagetops, imagetopdf, and imagetoraster filters.
6. Text files are continued to be accepted as print input, as it is a
convenient facility for system administrators.
7. bannertops will be replaced by a new bannertopdf which does not
accept image files as design elements any more, but instead accepts PDF
template files, and text sizes and positions (Lars Uebernnickel is
currently working on that).
8. (5) and (7) should eliminate the need of the libcupslegacy library as
the filter stack does not need to handle image files any more.
9. As all important applications (checked by standard Ubuntu Oneiric
installations) emit print jobs in PDF we consider the PDF printing work
flow as completed on the client side. On the server side it is currently
only completed on Ubuntu and Debian as distro patch, by adding the files
from (4) to the CUPS package. To complete it upstream originally it was
planned to get the files of (4) into CUPS upstream, but as CUIPS
upstream is moving most of the filters to OpenPrinting we will do the
upstream completion of the PDF printing workflow at OpenPrinting, via
(4) and discontinuing filters which are solely for the PostScript-based
printing workflow: bannertops, imagetops, texttops.
10. pstopdf will get continued for the few legacy applications which
still send PostScript and which we overlooked here. Usually these are
only apps which do not use standard libraries to create jobs and/or
which are not maintained any more upstream. Distros should not waste
time to patch unmaintained apps so that they send PDF. Distros can make
the installation of pstopdf optional, when a PostScript-emitting app
gets installed (via package dependencies, suggested by Lars Uebernickel).
11. The filter pdftops in conjunction with cpdftocps and pstops (still
part of upstream CUPS) form the "PostScript printer driver", as
PostScript is not the standard format any more and so PostScript
printers need a driver. These filters (at least pdftops and
cpdftocps) will get joined to one filter. Also commandtops (still
maintained by CUPS upstream) is part of the PostScript printer driver.
12. The build system will get modified to check whether the system's
CUPS is 1.5.x or 1.6.x (or later). In the former case filters still
provided by CUPS will not get installed by the OpenPrinting CUPS filter
package.
13. The CUPS legacy SVN repository will get observed and if further
components of CUPS get dropped into it we will decide on their continuation.
See also
https://blueprints.launchpad.net/ubuntu/+spec/desktop-p-new-cups-filters-package
and
https://www.linuxfoundation.org/collaborate/workgroups/openprinting/pdfasstandardprintjobformat
In addition to this, all printer driver suppliers/developers should get
informned about that the PostScript printing workflow is deprecated and
that they should nopt do anything which forces CUPS to generate
PostScript if the printer is not a PostScript printer.
Till
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