Re: 2.13.11-1: Y-offset for RehearsalMark?

[Joe Neeman]

On Sun, 2010-01-24 at 18:27 +0100, Alexander Kobel wrote:
> Dmytro O. Redchuk wrote:
> > Hi.
> > 
> > With this example: [...]
> >   \override Score.RehearsalMark #'Y-offset = #3
> > [...] 2.12.3 produces "correct" result ("as expected") while 2.13.11 ---
> > really unexpected. Attached, please, have i missed something?
> 
> Hi, Dmytro,
> 
> correct me if I'm wrong, but this looks like the A is actually higher 
> than the other two, and has it's baseline exactly 1 staff-space unit 
> above the top staff-line.  So I guess the Y-offset is calculated w.r.t. 
> the center staff line in 2.13 (Joe: is this a bug?), and you probably 
> have to increase the values by 2.
> For what you actually wanted, I recommend you use 
> 'outside-staff-padding, though.

It's a change in behaviour, but I don't think it's a bug (since the
Y-parents of grobs aren't documented anywhere).

Rehearsal marks used to have System as it's Y-parent, so Y-offset was
relative to the top of the system (but not including other grobs that
were created in the Score context, like BarNumber and MetronomeMark). In
other words, the reference point would change if, for example, there
were very high notes on a particular system. Now (for vertical layout
reasons) we move the Rehearsal marks into the top staff, so their Y
refpoint is the center line.

But anyway, I think 'outside-staff-padding is the right thing to do,
since its behaviour is actually documented and so it's much less likely
to change in future releases.

Cheers,
Joe