Re: [Groff] "creep" and booklets

[Tadziu Hoffmann]

> > Excellent idea! And thanks for the snappy response. This would
> > take the problem out of groff which would be a good thing for
> > this application (especially since the amount of creep required
> > =depends on the thickness of paper you are printing to, and I'm
> > much happier not to have to plant that in the groff source).

And the added advantage is that it also works for files not
created with groff.  Very nice.

By the way, if you make a few simplifying assumptions, it should
be easy to get an estimate of the creep value. If you imagine
that the "spine" forms a perfect half-circle (see picture below;
red is the staple; all pages should be aligned along the dashed
line) then you see that the successive shift between pages is
simply (1/2)*pi*(paper thickness).  Normal 80 g/m^2 copier paper
is about 0.1 mm thick (a stack of 500 pages is approximately
5 cm tall), giving a creep value of about 0.45 points.

----------------------------------------------------------------
%!PS
4 dup scale 30 100 translate .5 setlinewidth
1 1 10
{ dup 100 exch moveto -100 0 rlineto
  0 exch 0 exch 90 270 arc 100 0 rlineto }
for stroke
1 0 0 setrgbcolor 1 0 moveto -11 0 lineto stroke
0 setgray .1 setlinewidth [ 1 1 ] 0 setdash
0 -14.5 moveto 0 14.5 lineto stroke
showpage
----------------------------------------------------------------

> > For instance, I just tried it on a PS file (not from groff)
> > and it did not work.

> I don't know why this doesn't work on your PS file.

Was it a PS-file generated by acroread?  Acrobat inserts code to
center and scale the page contents if you select the option "fit
to page".  It assumes that the current clipping path corresponds
to the page size, and centers (and scales) the page contents to
fit into that area.  In this case "creep" would work if it also
manipulated the clipping path.