How does CUPS scheduler decide next filter / backend?
Michael Sweet
mike at easysw.com
Fri Nov 12 16:14:30 PST 2004
anonymous wrote:
> When CUPS scheduler calculates cost of filters, how does it know what file
> format (PCL/PS) backend is expecting?
It maps everything to the printers/name pseudo-type; the mapping
comes from the cupsFilter lines in the PPD file or an internal
mapping of application/vnd.cups-postscript to printers/name if there
are no cupsFilter lines in the PPD file.
> Basically I want to print PCL files to my PCL printer, but I don't want to
> create a special raw queue for that. (It doesn't make sense, ps, text,
> image, pdf all send to the same queue, why pcl file need to sent to a
> special queue?)
>
> I want to create a filter, and added an entry in *cupsFilter in the PPD
> file. How can CUPS know my pcl2pcl filter is the last filter?
Define the PCL file type, and then use:
*cupsFilter: "mime/type 0 pcl2pcl"
to pass those files through your filter.
> Another question is when pipe a couple of filters together, how could a
> filter know which / whether the user option has been processed?
It is basically implied by the output content type;
application/vnd.cups-postscript and application/vnd.cups-raster
have all options applied. Filters that produce them have to
ensure that the "universal" options are applied.
--
______________________________________________________________________
Michael Sweet, Easy Software Products mike at easysw dot com
Internet `Printing and Publishing Software http://www.easysw.com
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