On Fri, Aug 14, 2009 at 9:06 PM, Russ Cox<r...@swtch.com> wrote: > On Fri, Aug 14, 2009 at 5:37 PM, J.R. Mauro<jrm8...@gmail.com> wrote: >> IJS is probably it; that's the PCL driver for the home-office class printers. > > IJS is not PCL. > > IJS is a custom protocol that is spoken between a bitmap-producing > program like Ghostscript and a bitmap-printing program like /usr/bin/hpijs > http://svn.ghostscript.com/ghostscript/branches/mtrender/ijs/ijs_spec.pdf > > /usr/bin/hpijs speaks IJS to Ghostscript (or whatever is on standard > input/output) and speaks a new HP protocol called LIDIL to the printer > on the other end. Rather than commit to a full specification of LIDIL > and have to worry about backwards compatibility in the future, > HP chose to use IJS as a shim protocol and distribute a binary > that talks to the printer (source is available but it's still a binary). > > PCL is not in the picture. Getting PCL out of the picture is exactly > the reason that IJS and LIDIL were introduced, because LIDIL is > basically "here is a bitmap" whereas PCL is a real language that > requires actual memory and computing power inside the printer. > LIDIL moves the memory and computing requirements out of > the printer into the computer proper. > > Russ > >
I thought IJS was also used to turn a raster into PCL, since IIRC some non-business-class HP printers come with a stripped-down PCL 5e or some such. I'm probably wrong again, though. I try to not think about the HP PDLs too much. Probably it's not IJS I'm thinking of and some other cruft from HP -- it's been a long time.
