[Groff] The bottom is always ok, the head never is

[Miklos Somogyi]

Yes, you are right. This is about 
margins/headers/footers/vertical-positioning :-)

I use me (the macro package, I mean) to produce these things and more.
The problem is that I've never come across a figure showing exactly 
what these margins mean, from
top of page to the top or bottom of the header, etc.
No problem if the font size is zero, little problem (but problem) with 
font sizes of traditional reports.
With big fonts the problem could be big too.

Here's a layout test program. It draws a 2 mm resolution grid and 
selects font sizes with 6/12/18 mm
tall "H" characters for easy checking whether header/text/footer are at 
their right places.
You'll find that the footer is. The header is always low. How low, it 
depends on its font type and size.
The first line of text is low too, only accidentally ok.

Either I don't get something or the .he macro is wrong (I suspect that 
it confuses the top of the text
with the top of the character box, that is the height by point size, or 
it mistreats the hm register).
I don't have a clue what could be the problem with the 1st line of text.

------

The program also draws text at .sp |19.7c, that is 10 cm from the bot 
of page, and the text's top is really
at 10 cm height.
A smaller font at the same .sp |19.7c height plots something below the 
10 cm mark.
How do I explain this?

I'd be glad if you could straighten me out on these basics, what's 
what, what registers are involved,
how/why can fonts influence header height, etc.

Thanks,

Miklos

layout.grf
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Picture 1.pdf
Description: Adobe PDF document

Picture 1.pdf
Description: Adobe PDF document