Very Computer

I set up an output filter for a plotter that sizes the page to
fit the plotter roll. The filter worked fine last week; I was
able to type lpr -Pplotter filename.ps and have the postscript
file filtered correctly before it got passed to the plotter.
My printcap entry looks like:

################################################################
#
#HP Design Jet PostScript Plotter
#
plotter|HP Design Jet 650C PS Plotter:\
        :rm=pipeline:\
        :of=/usr/local/bin/plotter.of:\
        :sd=/var/spool/dj650c:\
        :rp=dj650c:\
        :lf=/var/spool/dj650c/ilog:\
        :sh:ms=-opost:
################################################################

Last Friday everything worked fine. Today, it doesn't work. The file
just gets printed directly to the plotter and the output filter
never gets invoked. Same printcap entry. Same filter. Same file.
As far as I know the line printer daemon is unchanged. What could
account for this mystery? Why would an output filter get ignored?
I tried creating a new device using a new output filter, it also
got ignored. Can someone kindly explain to me how to install
output filters correctly, or refer me to a reference for doing so?
I've read all the man pages that were directly relevant to this
question: printcap, lpr, etc, and I remain unenlightened.

Guy Berliner
--

Quote:>I set up an output filter [for lpr] for a plotter that sizes the page to
>fit the plotter roll. The filter worked fine last week; I was
>[...]
>Last Friday everything worked fine. Today, it doesn't work. The file

I've always found it easier to use an lpr shell script which calls the
real lpr, which offers a lot more freedom to me, and easier
customization.

I have a shell script "lpr" which processes lots of options, including
first/last page, resolution, file type, etc, and sends it to one of
two printers.  It's available on my (tiny) FTP site:  www.exc.com
(anonomous login) in /pub/lpr-joel/.

If you know any shell programming, you'll find it easy to customize.
It requires gs for printing ps files on non-ps-printers.  It required
dvilj2p for printing dvi files on lj printers, and dvips for printing
dvi files on ps printers, or via gs on lj printers (both are command
line options).

Enjoy.

-Joel

--
-----------------------------------------------------------------------------
|_|~~ Germany, Europe. 1940's ``A DISTINGUISHED speaker said that we must put
__|~| 16 Million DEAD.          our children first.   We in Bosnia wonder  if
                                we have any children left. Seven* thousand
 cnc  Bosnia, Europe. 1990's    children  have been killed  in Bosnia in  the
 cnc  HOW MANY MORE?            last three  years.   Those living, some  with
                                gray hair and eyes and hearts of old men, are
``May the world you             hardly children any more.''
  live in be the world                             - H. Silajdzic
  of your dreams.'' - Debbie Friedman                Prime Minister of Bosnia
-----------------------------------------------------------------------------

Quote:>I set up an output filter for a plotter that sizes the page to
>fit the plotter roll.

the Printing-HOWTO used to say, if output filters really are the right
answer, it must've been a very silly question.

so - why an output filter in particular? i'll admit i've never resized
output pages to fit any plotters, but i can't imagine why an if filter
shouldn't be able to do that.

Quote:> The filter worked fine last week; I was
>able to type lpr -Pplotter filename.ps and have the postscript
>file filtered correctly before it got passed to the plotter.
>My printcap entry looks like:

>################################################################
>#
>#HP Design Jet PostScript Plotter
>#
>plotter|HP Design Jet 650C PS Plotter:\
>    :rm=pipeline:\

ah, here might be the answer - you're plotting on another box. then,
i'll grant that if filters wouldn't get run; arguably this is neater
than the normally recommended workaround with an if filter that feeds
its output thru lpr to another printcap entry. still, if the one works
and the other not...

Quote:>Last Friday everything worked fine. Today, it doesn't work. The file
>just gets printed directly to the plotter and the output filter
>never gets invoked. Same printcap entry. Same filter. Same file.

if nothing changed on your machine, did anything change on the remote
machine? yes, i know that shouldn't change what filters your box runs,
but with lpr one never knows... if all else fails, try that hack with
a bogus local printer with the if filter (which should always get run)
piping its output to the real (non-local) printer. hey, it might
work...

Quote:>As far as I know the line printer daemon is unchanged. What could
>account for this mystery? Why would an output filter get ignored?
>I tried creating a new device using a new output filter, it also
>got ignored. Can someone kindly explain to me how to install
>output filters correctly, or refer me to a reference for doing so?

see the Linux HOWTO's on http://sunsite.unc.edu/mdw/linux.html .
some of them are decent general-purpose Unix material, and the ones
that deal with printing ought to be relevant to most all bsd-style
unices.
--
 "vi is my shepherd; i shall not font. in the name of edlin, and ex,
  and the holy post. :wq"