[Desktop_printing] What's the breakdown of vector printers vs.
mike at easysw.com
Tue Aug 1 07:41:08 PDT 2006
Fujinaka, Todd wrote:
> I'm hearing differing opinions about how many printers are vector (and
> non-Postscript) vs. printers which are raster-driven. In fact, I had two
> different people at OSCON ask, "Who needs OpenPrinting Vector anyway?"
> and "Who needs IJS anyway?" I don't have an answer to this, so I was
> wondering if those with more printer hardware knowledge could shed some
> light on this.
Nearly all inkjet, impact, and thermal printers are raster only.
High-end devices typically support PostScript, HP-GL/2, and in some
cases PDF, but the preferred format is still raster-based and highly
Most laser printers offer PCL 5 (raster), PCL 6 (aka PCL XL, a vector
language not at all similar to PCL 5), and PostScript support. Many
also support a vendor-specific vector format (Canon's LIPS, etc.)
Some support PDF and IPDS (a mainframe print protocol), both of which
offer both vector and raster printing.
All that said, many embedded PostScript interpreters are buggy and/or
slow, so you often have to use an alternate printer language to
bypass the interpreter bugs or get the full speed out of the device.
OpenPrinting Vector allows you to write a vector language driver for
printers that can be plugged into multiple print filters like Xpdf
and Ghostscript. Historically you've had to write a full Ghostscript
driver to do this - the intent is to separate the driver from
Ghostscript and simplify the development so that highly-optimized
drivers can be written for printers capable of efficiently printing
vector data instead of throwing high-resolution raster or PostScript
at the printer and waiting for the print to come out.
IJS was introduced as a way to work around the Ghostscript license.
You can write a driver program which uses the IJS protocol/interface
to provide raster printing from any IJS server (i.e. not just
Ghostscript). Because it doesn't depend on any of the CUPS libraries,
it is seen by some as a better alternative to the CUPS raster driver
approach. It also provides a way to override user settings via the
get/put_param interface, which you can't do with CUPS raster which
uses static UIConstraints in the PPD file...
Michael Sweet, Easy Software Products mike at easysw dot com
Internet Printing and Document Software http://www.easysw.com
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