[Openicc] Printing Plans, CPD and Gutenprint role of PPD

[Kai-Uwe Behrmann]

Am 01.03.11, 16:14 +0100 schrieb Jan-Peter Homann:
> Am 01.03.11 10:53, schrieb Kai-Uwe Behrmann:
>> 
>>> On the other hand, the developers at OpenICC , seem to prefer some ways, 
>>> which I don´t understand
>>> - the magic of CUPSicc...
>> 
>> Vendors deliver already PPDs for their printers. Its straight forward to 
>> deploy that existing mechanism. CUPS supports it already. The missing glue 
>> to Ghostsript and Poppler was the according pdftoraster filters. This will 
>> provide a improved out of the box experience once canned vendor profiles 
>> are shipped with the drivers. Till, Mike and others have done a great job 
>> around that. It is IMO pretty useless for user settings as it does not 
>> support much of calibration options. Hence we had criticised that in the 
>> past in that context. But for canned profiles its simple and good enough.
>
> I still don´t get the point:
> - How are driver settings and cannend profiles are integrated into the PPD ?

The ColorKeyWords PPD attribute would deliver some glue to integrate them.

> - How is the UI for for the printer chooser generated through the PPD ?
> - How is ensured, that the normal user can not change by chance the driver 
> settings in the chooser UI, leading to a mismatch of driver setting and ICC 
> profile ?

ColorKeyWords can be deployed to just use defaults for all colour related 
options other than the actual presented in the ICC selectors. That way 
gamma, brightness and contrast could be fixed, while the media could 
remain selectable.

> Thes PPD / CUPSicc concept seems still to be weak and intransparent to me 
> (and i´m profiling printers since more than 15 years...)

It is. On the other hand, that method is simple and allowes for a minimal 
package.
The ColorKeyWord PPD entry is one if the few way to solve this.
The other discussed approach is to add the calibration data right into the 
ICC profile. Edmund and Robert are working on exporting this calibration 
data from Gutenprint.

> If we want to have successfil user experience for the sRGB workflow with 
> cannend profile, we have to find a solution for the mentioned topics and we 
> should write down the solution in the OpenICC wiki.

At the moment the most relyable way is to remove all colour related 
alternatives from the PPD.
Then readd only colour related alternatives, which are specified in the 
cupsICCQualifer or the default ICC selectors (ColorModel, MediaType, 
Resolution). Thats as well described in the CUPS documentation as Till 
pointed out.
And then ship with the driver and the belonging ICC profiles.
The ICC profile installation path is left to be figured out.

Appearently that reminds to what most vendors offer on other platforms, 
a ICC mode without much options inside.

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