Re: Rest is in the wrong place

[Aaron Hill]

On 2020-10-13 5:42 am, Knute Snortum wrote:
> Although I was able to see the code working with the override in a
> minimum example, I couldn't get the override to work in the whole
> piece.  I may try to find a MWE of the problem, or I may just use the
> g4*1/2 solution.
>
> [...]
>
> I tried putting the override in global, in rightHand, and right before
> the measure with the rest too high.  The rest position did not change
> in any of those.  Is there a better place to put the override?

I would do this in the \layout block--either at the top-level or within 
your \score:

%%%%
\layout {
  \context {
    \Staff
    \override RestCollision.minimum-distance = #0.4
  }
}
%%%%

Note that the value of 0.4 was found experimentally using the MWE.  It 
is possible that your real score might need a smaller value.

----

If you do end up needing to use the g4*1/2 trick, here's a helper 
function that should make it cleaner to implement throughout your music:

%%%%
split =
#(define-music-function
  (fraction music)
  ((fraction? '(1 . 2)) ly:music?)
  (let* ((orig-len (ly:music-length music))
         (mom (ly:make-moment (car fraction) (cdr fraction)))
         (comp (ly:music-compress music mom))
         (comp-len (ly:music-length comp))
         (skip (make-music 'SkipEvent
                           'duration (ly:make-duration 0 0))))
    (make-sequential-music (list comp
      (ly:music-compress skip
        (ly:moment-sub orig-len comp-len))))))

%% { g4*1/2 s fis4 f }
%% becomes
%% { \split g4 fis f }
%%%%

The fraction defaults to half, but you can split at any other ratio if 
that is necessary.  For instance:

%% { g4*1/3 s4*2/3 fis4 f }
%% becomes
%% { \split 1/3 g4 fis f }

The main advantages of using this function are:

1. It does not impact assumed note durations.  In the examples above, 
fis properly inherits the quarter-note duration from g4 even though 
\split will modify the music.  The manual option changes the most 
recently used duration which requires explicitly qualifying fis as 
"fis4".

2. Should it be determined that the RestCollision behavior seen is a bug 
and that bug is resolved at a future time, it is much easier to find and 
remove usage of \split or just make \split a dummy function that does 
not modify music.


-- Aaron Hill