[Openicc] Google Summer of Code 2009: Oyranos CUPS backend

[Kai-Uwe Behrmann]

Am 17.05.10, 17:56 -0700 schrieb Hal V. Engel:
> This can be done currently on Linux (or other Unix) CUPS servers and work
> stations if the server admin adds a sym link to the correct location on the
> server.  Then workstation apps can use the CUPS API to retrieve the profile(s)
> as needed.  The current Oyranos CUPS code supports this but the only place
> where the sym link is documented is in the OpenICC GSoC email list since at
> the time this work was done this was thought to be temporary.  There is also
> an open enhancement request in the CUPS tracker to make it so that server
> admins do not have to create the sym link for this to work.  I don't know the
> status of this tracker item.

I tried with CUPS-1.3.11 (openSUSE).
$ ln -s /usr/share/color/icc /usr/share/cups/profiles/openicc
$ wget http:/localhost:631/profiles/openicc/sRGB.icc
HTTP request sent, awaiting response... 404 Not Found
Would have been glad to read it has changed:
http://www.cups.org/str.php?L2894

Oyranos' CUPS module can a cupsICCProfile name and map that to a local 
installed profile, if the profile resides in a OpenICC colour path. I just 
tested that with kolor-manager.
To get CUPS and OpenICC profile paths together, one needs to link the 
OpenICC path to the CUPS one, e.g.:
$ ln -s /usr/share/color/icc/devices/gutenprint /usr/share/cups/profiles/gutenprint
and write
*cupsICCProfile .Plain./Description: "gutenprint/my_printer.icc"

The http request to CUPS fails but Oyranos can at least resolve the 
profile on a local host. Note: linking /usr/share/color/icc/ to something 
like /usr/share/cups/profiles/openicc will not work.
Still nothing working in the net.


To summarise:
* cupsICCProfile is parsed by Oyranos CUPS module in git
   - the vendor or admin configured profiles can be obtained localy only
* "colourKeyWords" allows to match more precise print conditions to a
   ICC profile
   - works for user configured profiles
   - works for ICC profile (print) vendors
   - works as well only localy


One further and related problem is a missed definition for marking 
prematched data.
If someone creates a local proof and sends that ready for printing to a 
remote host, the colours are in danger to be double colour converted.
If adding more rendering options to PPD like CMM selection, rendering 
intent, BPC and so on provides a sufficient alternative is not yet clear 
to me.


kind regards
Kai-Uwe Behrmann
-- 
developing for colour management 
www.behrmann.name + www.oyranos.org