Re: [Groff] Problem with bottom page margin in MM

[Tadziu Hoffmann]

> I  didn't  understand how your code will work. The
> address@hidden trap performs a move to a position spec-
> ified by an absolute distance, while you only pro-
> pose to change the line at which the trap is trig-
> gered.  This will not change the way it prints the
> footnotes, because  it  uses  absolute  addressing
> inside.

If you enable the debugging output in address@hidden,
you'll see that in this particular example pg*foot-trap is
made up of pg*footer-size (the exact height of the footer)
and ft*note-size (the exact height of the footnotes).
Thus, if you space absolutely to \\n[pg*foot-trap]u+1v
before outputting the footnotes, these will intrude 1v
into the bottom margin.  That's why the "+1v" is wrong.

So address@hidden contains the complete reserved height at
the page bottom which the running text must not step into.
Since it's possible that the line that triggers the trap
can overstep the trap position by almost up to 1v, we
have to set the trap position accordingly almost 1v higher,
except in nroff, where trap positions are reached exactly.
(It's preferable to have a little extra space between the
last line and the footnotes than too little.)


> .am address@hidden
> .   if n \{\
> .      if \\n[ft*note-size]>0 .nr pg*foot-trap -1v
> .   \}
> ..

I think that leaves you with more space before the footnotes
than necessary in nroff (but the bottom margin is okay),
but in troff you still have the problem that the footnotes
get printed 1v into the bottom margin.