[Openicc] Assuring that all CUPS filter chains under Linux accept ICC profiles

[Till Kamppeter]

Hi,

I have done the first release of the new OpenPrinting CUPS Filters 
package on OpenPrinting (see new item on http://www.openprinting.org/), 
giving an upstream home to the new CUPS filters for the PDF-based 
printing workflow and also for the filters which will get dropped by 
CUPS from version 1.6.0 on.

Now we need to check whether we can really use ICC profiles with all 
printers and drivers under Linux.

Thanks to the great work of Richard Hughes CUPS and at least the 
Ghostscript rendering filter gstoraster (PDF or PostScript to CUPS 
Raster) accept both user-assigned ICC profiles through colord and 
print-queue-assigned ICC profiles through the *cupsiccprofile keyword.

This will at least make filter chains like these color-managed:

[PDF]->pdftopdf->gstoraster(GS)->rasterto...->[printer]

Now there are also these chains:

[PDF]->pdftopdf->pdftoraster(Poppler)->rasterto...->[printer]
[PDF]->pdftopdf->pdftops(GS)->[PostScript printer]
[PDF]->pdftopdf->pdftops(Poppler)->[PostScript printer]
[PDF]->pdftopdf->foomatic-rip(GS)->[printer]
[PDF]->pdftopdf->foomatic-rip(Poppler)->[printer]
[PDF]->pdftopdf->pdftops(GS)->ps-based-driver->[printer[
[PDF]->pdftopdf->pdftops(Poppler)->ps-based-driver->[printer[
[PDF]->pdftopdf->[PDF printer]
[PDF]->pdftopdf->gstopxl->[PCL-XL printer]
[PDF]->pdftopdf->pdftoopvp(Poppler)->[printer]
[PDF]->pdftopdf->pdftoijs(Poppler)->[printer]

Assuming CUPS, cups-filters, ghostscript, and Foomatic are the current 
VCS states, which of these chains do already support color management, 
and which of the two forms (*cupsiccprofile for queue-based ICC and 
colord for user-supplied ICC)?

I am very grateful for patches covering the not-yet-covered filter chains.