Filters and backends for CUPS Files

This filter converts, depending on how it is called, PostScript of PDF input to

output format					filter called as
----------------------------------------------------------------
PDF						gstopdf
PostScript					gstops
PCL-XL						gstopxl
XPS (XML Paper Specification)			gstoxps
text (UTF-8 encoded)				gstotxt
CUPS-raster					gstoraster
PWG-raster					gstopwgraster
URF (Apple's proprietary raster format)		gstourf

By design, the filter accepts all job attributes normally processed by the 
pstops (or pdftopdf) filter except number-up, number-up-layout, page-border,
and same-up.
In case of PDF ot PostScript output, attributes not handled by Ghostscript
are processed by the pstops or [cg]pdftopdf filter called as a subprocess.

The job attributes page-ranges, page-set, fit-to-page, collate=true,
and outputorder=reverse are accepted if the used Ghostscript release 
supports the corresponding command line options;
if not, the filter stops with an error message.

Except for the conversion to the urf format, all data handling
is performed by Ghostscript; the full fuctionality is guaranteed
with Ghostscript releases 9.20 and above.