🚀 go-pugleaf

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The limited printing area on the LaserWriter has always annoyed me.
Try the following "beefed-up" code to display your available
page area:

   clippath
   gsave 0.8 setgray fill grestore
   14.4 setlinewidth 0 setgray stroke
   showpage

The 14.4 line is 0.2 inches, but the path is the boundary of
the clipping region, so the outer 0.1 inches get clipped off by
the PostScript interpreter. Using commands like "letter" and so
on will change the default clipping path and so have an effect
on the rectangle that gets printed.

However, if you expect to see your LaserWriter print a grey
rectangle with a 0.1 inch black border around it - think again!
What you will get is a grey rectangle with a 0.1 inch black
border round most of it, but there will be at least one edge
where the black border is thinner or even completely missing.

Why? The answer is that the printer *hardware* performs
clipping as well, so PostScript is preparing a bitmap that the
printer won't even bother to try to print. By putting sticky
tape over the notches in the side of the paper tray you can
trick the hardware into believing it has a different sized
piece of paper, so it will change the clipping area
appropriately (incidentally, PostScript uses those notches as
well when deciding the default clipping path).

How can you get the software clipping region inside the
hardware clipping region, so that you at least get all of the
bits that PostScript has so lovingly prepared?  That is the
function of the "setmargins" primitive: note also that the
version 3.0 PostScript interpreter has fixed a bug/feature so
that changing the margins doesn't change the meaning of (0,0)
any more.


PLEASE PLEASE PLEASE - can someone tell me how to tweak the
horizontal & vertical position of the hardware clipping? I
refuse to believe that they aren't adjusted by some variable
resistor somewhere, but everytime I give the above lecture to
an engineer/Apple techie/salesman I get blank looks and
absolutely no information whatsoever.

-- 

William Roberts         ARPA: liam@cs.qmc.ac.uk  (gw: cs.ucl.edu)
Queen Mary College      UUCP: liam@qmc-cs.UUCP
LONDON, UK              Tel:  01-975 5250