[Openicc] - CM Framework - Printer Driver -

Till Kamppeter till.kamppeter at gmail.com
Tue Jun 21 09:00:21 PDT 2011

On 06/21/2011 05:48 PM, Richard Hughes wrote:
> Right, but what actually spawns the rasterto... binary?

CUPS spawns it. CUPS reads the PPD file and sees in a cupsFilter line 
that the driver needs CUPS Raster as input and that the driver itself is 
the filter named rasterto... This means that CUPS builds a filter chain 
which turns the incoming data into CUPS Raster and adds the rasterto... 
filter to the end of the filter chain. This leads to the printer's data 
format being generated at the end and sent to the backend.

> I assume
> cupsd, but the color profile information is at the moment only
> available in the foomatic and gstoraster filters.

The ICC-profile-based color correction is done by the renderer/RIP 
(filter to turn high-level input, usually PostScript or PDF into raster 
output), which is usually Ghostscript (but can also be Poppler). In case 
of CUPS Raster drivers (rasterto..., like Gutenprint) the gstoraster 
filter (Ghostscript 9.03 and newer) is used as Ghostscript wrapper, for 
other drivers usually foomatic-rip.

So the rasterto... filters do not need the ICC profile itself and the 
driver option settings they get via the fifth command line argument.

> Sorry if it's a stupid question.

No problem.


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