is at the core of the CUPS filtering system. It is responsible for the first
stage of the rasterization process. Its input is of MIME type application/vnd.cups-postscript; its output is
application/vnd.cups-raster. This output format is not yet meant to be printable. Its aim is to serve as a
general-purpose input format for more specialized
that are able to
generate device-specific printer data. This is shown in
the PostScript to
Intermediate Raster Format diagram.
Figure21.6.PostScript to Intermediate Raster Format.
CUPS raster is a generic raster format with powerful features. It is able to include per-page information,
color profiles, and more, to be used by the downstream raster drivers. Its MIME type is registered with IANA
and its specification is, of course, completely open. It is designed to make it quite easy and inexpensive for
manufacturers to develop Linux and UNIX raster drivers for their printer models should they choose to do so.
CUPS always takes care of the first stage of rasterization so these vendors do not need to care about
Ghostscript complications (in fact, there are currently more than one vendor financing the development of CUPS
raster drivers). This is illustrated in
the CUPS-Raster Production Using
Figure21.7.CUPS-Raster Production Using Ghostscript.
CUPS versions before version 1.1.15 shipped a binary (or source code) standalone filter, named
, which was derived from GNU Ghostscript
5.50 and could be installed instead of and in addition to any GNU or AFPL Ghostscript package without
Since version 1.1.15, this feature has changed. The functions for this filter have been integrated back
into Ghostscript (now based on GNU Ghostscript version 7.05). The
now a simple shell script calling
If your Ghostscript fails when this command is executed:
gs -h |grep cups
, you might not
be able to print, update your Ghostscript.