Re: Fullpage Image Using PDFPIC/PSPIC

[Dave Kemper]

Alexis,

Out of curiosity, which version of groff are you using?  Most users
are on 1.22.4 these days, that having been the latest release for
about four years, but a few users build their own groff from git
sources.

I ask because this clarifying explanation from Deri:

On 1/11/23, Deri <deri@chuzzlewit.myzen.co.uk> wrote:
> Groff's concept of an absolute position is where it would start the next text
> glyph on the page, so it is the base line of the current font. That is why 0,0
> appears 1v down from the top, if you were to print glyphs the tallest glyph in
> the font should be 2p from the top edge, this is because the default values
> for ps/vs are 10/12.

concerns a point that was misleadingly documented in 1.22.4 and
earlier releases but has since been updated in git.  So if you were
using the latest-from-git documentation and still found this
confusing, it suggests more work could be done here.

In particular, 1.22.4 documented that for vertical movements, the |
operator measured "from the top of the page"; commit 9ee52970
(http://git.savannah.gnu.org/cgit/groff.git/commit/?id=9ee52970, made
in response to http://savannah.gnu.org/bugs/?60820), clarifies that it
measures "from the first text baseline on the page..., using the
current vertical spacing."  This new text may have explained the
situation to you.

However, your issue brings up the point that what groff considers the
"top of the page" affects things besides the | operator, so I wonder
if this explanation should be generalized a bit more in the manual.