🚀 go-pugleaf

rberlin@birdlandEng.Sun.COM (Rich Berlin) suggests the following, in the
course of trying to get rid of page width hard-wired into a piece of
PostScript from an earlier article:

> ...The PostScript interpreter can
> ALWAYS tell your program the size of the page.  Add the following
> procedure to your bag of tricks:
> 
> /printable-area { % - => llx lly urx ury
>    gsave clippath pathbbox grestore
> } bind def

The procedure gives just what it says--the printable area.  This is seldom
the same as the page size, because most printers have to provide a "margin"
so they won't try to dump toner off the edges of the paper.  (It also
reduces the memory for the page bitmap a little.)

A reasonable guess is that the margins on the printable area will be
symmetric, so adding llx to urx should give the page width.  (No guarantee
there, of course; it's just a good guess.  x symmetry is more likely than
y.)

Also...Rich suggests mirror-imaging as follows:
> printable-area   % stack: llx lly urx ury
> 0 exch                  % llx lly urx 0 ury
> translate               % llx lly urx 
> pop pop pop             % -
> -1 1 scale

Aside from the margin problem, this looks to me as if it translates up to
the top of the page (using 0 ury) as if to prepare for a vertical reflec-
tion, then does -1 1 scale, which is a horizontal reflection and will throw
the image off the page above and to the left.
-- 
Dick Dunn     rcd@ico.isc.com -or- ico!rcd       Boulder, CO   (303)449-2870
   ...Lately it occurs to me what a long, strange trip it's been.