Re: Should vertical motions be in vees or ems? Where does the baseline go?

[Dave Kemper]

On 11/13/21, Ralph Corderoy <ralph@inputplus.co.uk> wrote:
>> What would an ideal model of output from the above input look like?
>
> What's the argument against CSTR 54's section 11.1 definitions being the
> ideal?

Two are:
 - General typographic convention is to measure vertical motions in
v's, not m's.  CSTR #54's definitions of \u, \d, and \r do not align
with this common expectation.
 - CSTR #54 is not even internally consistent in this regard: most
vertical motions are specified in v's.  \u, \d, and \r are outliers
even in troff-land.

Determining what historical troff did is tougher unless you have a
Graphic Systems C/A/T lying around: a code analysis in
http://savannah.gnu.org/bugs/?60602#comment1 concluded CSTR #54 was
incorrect about troff's behavior on this point.  But Heirloom troff's
behavior, if a legitimate proxy for AT&T troff, calls that conclusion
into question.