Re: [Groff] chop in pic?

[Werner LEMBERG]

> > I could generalize pic's syntax of compass points with something
> > like:
> >
> >   deg = atan2(0, -1) / 180 ;
> >   move to last ellipse .angle deg * 217 ;
> >
> > This would specify a point on the ellipse with an angle of 217
> > degrees (in the mathematical sense, i.e. counter-clockwise from
> > the right).
>
> Not bad.  Do any of the other .pos notations take a parameter?

No, but I don't think that this causes problems.  Before making the
suggestion I've actually checked pic's source code :-)

> If not, perhaps a function would be better.
>
>     ellipseperim(E.c, E.w, E.h, theta)
>
> returning a point.

Hmm, my suggested generic `compass point' should work with any object;
it wouldn't be restricted to ellipses.

> I'm not sure.  Also, there will always be other things that wouldn't
> be handled like the intersection of two lines, or an arc and a line,
> etc.  Perhaps it's best to leave the simple case to chop and provide
> examples showing that the others are up to the author.

Well, implementing Metafont's or Metapost's `intersectionpoint'
keyword is probably too much work...

BTW, I've almost finished support for Metapost in groff.  This means
that users who aren't satisfied with pic can always use the `greater
brother' Metapost.  More to be announced soon on this list.


    Werner