[Openicc] CUPS Color Management under Linux gets into distros

[Koji Otani]

From: Till Kamppeter <till.kamppeter at gmail.com>
Subject: Re: [Openicc] CUPS Color Management under Linux gets into distros
Date: Wed, 09 Feb 2011 00:21:55 +0100
Message-ID: <4D51D013.70203 at gmail.com>

till.kamppeter> On 02/09/2011 12:12 AM, Chris Murphy wrote:
till.kamppeter> > On Feb 8, 2011, at 9:33 AM, Till Kamppeter wrote:
till.kamppeter> >> we will have some color management in a distro soon. I have added Koji
till.kamppeter> >> Otani's Poppler-based pdftoraster filter to the CUPS package for
till.kamppeter> >> Ubuntu Natty (release end of April, currently available as the
till.kamppeter> >> development branch of Ubuntu) and Debian unstable. This pdftoraster
till.kamppeter> >> filter replaces the one shipped with Ghostscript and in addition to
till.kamppeter> >> being much faster and more reliable with complex PDFs it implements
till.kamppeter> >> CUPS' ICC profile support as described in the documentation:
till.kamppeter> >>
till.kamppeter> >> http://www.cups.org/documentation.php/doc-1.4/spec-ppd.html#cupsICCProfile
till.kamppeter> >> http://www.cups.org/documentation.php/doc-1.4/spec-raster.html#TABLE2
till.kamppeter> >> http://www.cups.org/documentation.php/doc-1.4/raster-driver.html#COLOR
till.kamppeter> >>
till.kamppeter> >> Otani-san, am I correct that with this pdftoraster we have ICC-profile
till.kamppeter> >> support for CUPS Raster drivers as described in the CUPS doc? How do I
till.kamppeter> >> supply a rendering intent? Are there any additional non-PPD options to
till.kamppeter> >> supply to print jobs?
till.kamppeter> >> Color management experts from OpenICC and driver developers, please
till.kamppeter> >> test this feature and report your experience here. You could ship ICC
till.kamppeter> >> profiles for installation in /usr/share/cups/profile/ to improve your
till.kamppeter> >> printer's output quality.
till.kamppeter> >> Color management experts from OpenICC, WDYT about this color
till.kamppeter> >> management effort? Is this already a step forward? Is it at least the
till.kamppeter> >> correct effort for consumer-level printing? What needs to be added to
till.kamppeter> >> support pro and prosumer printing?
till.kamppeter> >
till.kamppeter> > Seems to me any pdftoraster filter needs to honor the PDF contents,
till.kamppeter> > not do extra things on its own. Or we run into trouble.
till.kamppeter> > So if this pdftoraster honors ICCBased without substitution, that's
till.kamppeter> > good. If its implementation of CUPS ICC profile support means that it
till.kamppeter> > uses externally referenced profiles as the destination profile, that's
till.kamppeter> > fine *UNLESS* the PDF print spool file contains an OutputIntent in
till.kamppeter> > which case that needs to be used. So does pdftoraster support
till.kamppeter> > OutputIntent?
till.kamppeter> 
till.kamppeter> I do not know. Otani-san, can you answer Chris' question?
till.kamppeter> 
till.kamppeter>    Till
till.kamppeter> 

pdftoraster doesn't support OutputIntent now,
INTENT_RELATIVE_COLORIMETRIC is hardcoded.
Should it take OutputIntent from cupsRebderingIntent Page Device
Attributes in PPD ?

As Mr. Engel wrote, poppler doesn't support rendering intent in PDF content,
INTENT_RELATIVE_COLORIMETRIC is hardcoded in it.
This is because that too many changes on poppler were needed
when I created patch for poppler.

-------
Koji Otani