I've used the hack in the Lilypond docs for getting dynamics centred
between the staves of a PianoStaff, but I would like to make it more
convenient to do other markings. At the moment, I can write something like
s1\f
to get a piano dynamic which is nicely centred, but if I write another
marking, e.g.
s1^\markup { espress. }
then it's too high (or I can try s1_\markup { ... }, but it's too low). I
can't use \markup without ^ or _ because then I'm not in Lyric mode, which
is how markings seem to be implemented. Basically I'd like another hack
that reverses the raising effect of ^, so that I can use ^ and the text
generated by markup will be level with the dynamics generated by the
dynamics commands. Of course, I don't want to have to put a \raise command
before every \markup.