Horizontal centering \startlines...\stoplines

[Steve Lumos <slumos@nevada.edu>]

Hi.

I've just recently started using ConTeXt for the purpose of
typesetting a poetry chapbook (small, usually self published,
typically saddle stitch bound).  I can't begin to tell you how much I
love how easy the layout becomes with ConTeXt.

What I'm wondering is whether there is an automatic way in ConTeXt to
horizontally center a poem (or any fairly long block of short-line,
ragged-right text) on the page.  For example I would like to do
something like:

\definehead[Poem][subject]
\setuphead[Poem][alternative=middle,textcommand=\ss]

\setupindenting[big]
\setuplines[indenting=even]

\starttext

\Poem{deMorgan}
\startlines
Great fleas have little fleas
    upon their backs to bite 'em
And little fleas have lesser fleas,
    and so ad infinitum,

And the great fleas themselves,
    in turn, have greater fleas to go on,
While these again have greater still,
    and greater still, and so on.
\stoplines

\stoptext

except wrapping the \startlines...\stoplines in some magic so that the
poem is beneath the title and without having a human to measure with
width of the widest line.  This is especially important for setting
poems in two columns because in that case the title looks strange no
matter where you put it.

With LaTeX in the past, I have either lived with everything on the
left which makes the title look funny, or resorted to putting each
poem in a minipage of a width found by trial and error.

Steve