Path: utzoo!utgpu!cunews!micor!latour!ecicrl!clewis
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Newsgroups: comp.lang.postscript
Subject: Re: How do I determine a printer's imaging area?
Keywords: PostScript, imageable_region, margins, incompatibility
Message-ID: <1341@ecicrl.ocunix.on.ca>
Date: 12 Feb 91 20:26:03 GMT
References: <1991Feb8.174934.5816@eagle.lerc.nasa.gov> <7723@exodus.Eng.Sun.COM> <37288@netnews.upenn.edu>
Distribution: na
Organization: Elegant Communications Inc., Ottawa, Canada
Lines: 37

In article <37288@netnews.upenn.edu> choma@scotty.dccs.upenn.edu (Peter Choma) writes:

>    One area of PostScript incompatibility is the imageable region. For example,
>the Apple LaserWriter has top and bottom margins of 0.04 while the NEC LC890
>PostScript printer has top and bottom margins arround 0.22 inches.

>    If you assume a value of 0.25 inches for each margin (top, bottom, left, 
>and right) and a letter paper size of 8.5 by 11.0 inches, you should be able
>to print on most PostScript printers without having to ask the printer for
>its imaging area - ie. Scale your image to be 8.0 by 10.50 inches centered 
>within a 8.5 by 11.0 inch region.

I took a different approach with psroff (CAT Troff to postscript/lj converter).
I don't force a .25 inch margin OR scale 11 inches into 10.5.  After a great
deal of thought (and some reports from elsewhere) I came to the conclusion that:
	a) it's rude to scale the output of troff because oft-times the
	   troff actually has absolute measurements, and one would want
	   them to come out accurately.  So that people could use
	   a ruler to determine the commands to issue (I'm taking "Scale
	   your image" literally)  (This was very important to me because
	   I was doing some "real" publishing)
	b) an explicit .25" horizontal shift doesn't always do the trick.
Psroff has several options to shift the image vertically or horizontally to
fit in with specific printers, but none of these are hardwired into the
converter itself.  Fortunately, none of the troff macro sets I've seen plant
anything too high or too low.  Most CAT troff macro sets have a ~.5i right
shift to begin with, and I add another offset (default .5i) to permit
proper page centering.  It all works pretty good.

When you're drawing an image manually, on the other hand, it's more
useful to assume a (0,0) origin and possibly even a (1.0,1.0) upper right
corner, then scaling/translating to fit is a lot easier.
-- 
Chris Lewis, Phone: (613) 832-0541, Internet: clewis@ferret.ocunix.on.ca
UUCP: uunet!mitel!cunews!latour!ecicrl!clewis; Ferret Mailing List:
(ferret-request@eci386); Psroff (not Adobe Transcript) enquiries:
psroff-request@eci386, current patchlevel is *7*.