Re: Avoids calling pure calculations too far downstream and avoids triggering quanting too far upstream (issue 12951044)

[k-ohara5a5a]

> > If the spanners have never successfully responded to the position of
> > cross-staff support, we should just skip cross-staff items from the
> > support.
> >

> This is a great idea, but I'm not sure the best way to implement it.
> It's not possible at the engraver stage when the grobs are originally
put in the
> list.
> And it's kinda kludgy to check for it every time we extract the grob
set.




https://codereview.appspot.com/12951044/diff/5001/lily/side-position-interface.cc
File lily/side-position-interface.cc (right):

https://codereview.appspot.com/12951044/diff/5001/lily/side-position-interface.cc#newcode305
lily/side-position-interface.cc:305: aligns_to_cross_staff |=
cross_staff;
You already check all the 'support' for cross-staffitude every time you
unpack the list.  I am beginning to doubt that the special case for
aligns_to_cross_staff has any effect.

If the code has not succeeded in considering cross-staff support, skip
them up above
if (!me->"cross_staff" || e-> "cross-staff" ) continue;

https://codereview.appspot.com/12951044/diff/5001/lily/side-position-interface.cc#newcode373
lily/side-position-interface.cc:373: dim.set_minimum_height
(dim.max_height ());
Really?  If a spanner lies over one cross-staff grob, draw a box around
*all* the grobs in the support, whether cross-staff or not ?

https://codereview.appspot.com/12951044/