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

[Richard Hughes]

On 28 February 2011 15:42, Jan-Peter Homann <homann at colormanagement.de> wrote:
> First you write "the PPD is never changed"

The PPD file on disk is never changed.

> For the use case "Importing new settings witth assigned bundled profiles"
> you write that CUPS reads the PPD file, when the printer is connected.
> This doesn´t go together in my head.. (may be I´m too dumb...)

No, you're not dumb, this stuff is really complicated. CUPS reads the
PDD file from the file system when the printer is connected. If the
PPD references any ICC profiles they are added to colord as fallbacks
if the user or distributor does not specify any profile to override
them. colord is really just a simple mapping agent between devices to
profiles.

> If we have the ability to export and import driver settings with assigned
> /bundled profiles, such settings will never be part of a standard PPD. We
> also should be able to handle the case of several sources, which may offer
> driver settings with assigned /bundled profiles. (Imagine e.g. different
> media vendors offering profiles for their media).

I'm not sure "exporting" a device to profile mapping make much sense.
It would be much better if the profile had metadata that could
automatically generate qualifiers on the host system. For instance,
RGB profiles can have the "rgb.*.*" profile, or is there is some kind
of paper_type=matte metadata then this can be auto-added as
"rgb.matte.*".

All the media anufacturers would need to do is add a DICT entry of
"paper_type=matte" to the ICC profile and it would magically be used
for matte paper if the profile is mapped to the device. Note: the
"paper_type=matte" is an example, and it probably makes sense to
standardize this with oyranos like we already have done with the
edid_FOO options. But it's certainly a nice touch to make everything
"just work".

Richard.