Re: [Groff] question about .rs and .nop

[Tadziu Hoffmann]

> Some years ago, I wrote about the annoyance of absolute .sp
> requests, which do not, contrary to intuition and logic,
> take the top of the page as their starting point but rather
> the top of the page plus 1v.  Classic example:
>
>  .vs 12p
>  .sp |6P
>  foo
>
> "foo" is printed 6 picas plus an additional 12 points
> below the top of the page, requiring .sp |6P-1v to place
> it correctly at 6 picas.

> There'd be no need for complications like @TOP if groff had
> an absolute spacing request that spaced sensibly to the
> requested absolute position on the page; in other words,
> "|6P" means "6P from the top of the page", end of story.

I guess you're annoyed because you're thinking in terms of
baselines (which, to be fair, is how practically all low-level
printer languages are actually designed these days).

However, if you come from a background of lead typesetting
I could imagine this sounds perfectly natural, because it
simply means "add this much spacer and then put the next
composed line of text below it".

Of course troff then makes the crude approximation that the
baseline of the text sits at a full baseline distance below
its total height, which is not true.  Groff has fixed this by
implementing "post" vertical line spacing ("pvs"; so that the
total baseline distance is "pvs"+"vs", and the normal "vs"
may then be thought of as the "pre" vertical line spacing),
but I've never actually seen this being used in practice.