[Openicc] Photoprint as CUPS driver ??

[Alastair M. Robinson]

Hi :)

On 07/03/11 12:43, Jan-Peter Homann wrote:

> So far a s I know, is Photoprint a standalone application, which uses
> Gutenprint, lcms and ArgyllCMS.

Photoprint doesn't directly use ArgyllCMS (CMYKTool does, but not 
PhotoPrint) - other than that, yes. :)

> How big would be a amount of work, to reuse some code of Gutenprint and
> create a "Photoprint CUPS driver" which could be used CUPS raster driver ?

I've already done such a thing in the past, but it was a bit of a 
lash-up.  Instead of having printer options in the PPD, the PPD 
contained a list of what Edmund calls "Prosets" - pre-packaged bundles 
of settings and an associated printer profile.  It works well as a 
walled-garden, but it's not flexible, and being a lash-up was a pain to 
administer!

Now that both Ghostscript and Poppler support ICC profiles, I don't 
think there's any need to re-use code from PhotoPrint, though - we 
already have rastertogutenprint, and if that can receive colour-managed 
data from pdftoraster, then that part of the workflow is solved.

> The functions of this Photoprint CUPS driver should be as following:
> - Gutenprint setup (for internal queues) inside the driver

I'm not sure I follow you.  Internal queues?  Do you mean you envisage 
PhotoPrint as being a intermediary, offering its own options via a PPD 
and hiding the Gutenprint ones?  Or something else?

> - print testcharts from inside the driver

PhotoPrint could certainly form the basis of tool for profiling and 
calibrating, if (as seems likely) we end up without a clean way of 
bypassing the printer profile / calibration.  As Graeme rightly says, 
though, it's easy to end up in a situation where two distinct paths to 
get out of sync with regard to colour response.

> - Assigning of ICC profiles or direct profiling for every queue inside
> the driver

> - use of a folder for printer ICC profiles, which could be used also for
> cupsICCprofile workflow

Yes, we'll need that at some point.

> - Import the Gutenprint PPD of the choosen printer
> - Enhance the PPD with the icc profile of every queue configuration for
> cupsICCprofile workflow
> - Save enhanced PPD
> - pass through of non color related PPD settings to Gutenprint

Again, I'm not sure quite what you have in mind here, or where 
PhotoPrint would fit in.  PhotoPrint currently ignores PPDs as much as 
possible, and only uses them to (a) identify the printer driver to use, 
and (b) feeds them to Gutenprint when a Postscript printer queue is used.

> The tasks which should be possible with ths Photoprint CUPS driver
> should be as following
> - usage in a CUPS sRGB workflow with either GhostScript or poppler as
> xxxtoraster

Well both now support basic colour management.  Ghostscript's is closer 
to being fully functional, supports CMYK, should soon support 
OutputIntent and various other improvements.  Poppler, I fear, may turn 
out to be a bit of a dead end in terms of colour-management.

> I depending on the amount of work and motivation of a developer, I would
> sponsor the development with a monthly fee.

It would be a significant amount of work, and as I say, I'm not sure how 
much help PhotoPrint's codebase would be.  Currently it could be used as 
a replacement rastertogutenprint, and could be used to convert rasters 
from a known source space to a selected printer profile.  If pdftoraster 
(and pstoraster) are going to support colour-management, then that's not 
needed.

All the best
--
Alastair M. Robinson