Re: "Ghost" trills

[David Sumbler]

Hi Mark, thanks for your response.

But the code doesn't compile correctly under 2.20, at least, not on my
computer.

What it does is throw out a number of error messages stemming from the
fact that \partCombine is not recognized.  And, true, it doesn't have
the unwanted trills.  But it is not combining the parts on the second
system, as can be seen if you change one of the bars to a couple of
minims, say, instead of a semibreve.

If \partcombine is substitued for \partCombine, so that 2.20 recognizes
it, then the parts combine correctly on the second system, but we also
get these wretched unwanted trill spanners.

David

On Thu, 2020-08-06 at 11:15 -0700, Mark Stephen Mrotek wrote:
> David,
> 
> It compiled correctly under 2.20.
> 
> Mark
> 
> -----Original Message-----
> From: lilypond-user [mailto:
> lilypond-user-bounces+carsonmark=ca.rr.com@gnu.org] On Behalf Of
> David Sumbler
> Sent: Thursday, August 6, 2020 10:12 AM
> To: lilypond-user@gnu.org
> Subject: "Ghost" trills
> 
> Having implemented some of the methods shown in Vaughan's marvellous
> tutorial at 
> https://lists.gnu.org/archive/html/lilypond-user/2020-06/msg00114.html
> I have been making rapid progress in setting the orchestral piece
> which is my latest project.
> 
> But suddenly I came across a problem which, try as I might, I can't
> figure out or solve.   I have managed to work around it.  Despite
> that
> I should very much like to understand what is going on here so that I
> will be better able to deal with similar or related problems in
> future.
> Also the work-around makes my input code considerably more complex,
> and may not work well if line breaks get moved around.
> 
> The problem is that, after using trillspanners, sometimes the trill
> reappears later on after a change of staff setup.  The code below
> reproduces this problem.  I have also attached a pdf file containing
> the output.
> 
> In this example, it is quite easy to get rid of the unwanted
> trillspanners in the second line by making small, apparently random,
> alterations in the input.  For instance, if the 4th bar in the upper
> instrument is changed to 2 minims, or the same bar in the lower
> instrument is changed to a semibreve, the rogue trillspanners
> disappear.  However, it is not true  to say that the trillspanners
> always disappear whenever the rhythms in the two instruments are
> exactly the same, and of course it wouldn't be a useful solution to
> the problem even if it were true.  In fact, in my actual score the 2
> instruments do have identical rhythms, but I still get these unwanted
> trills in the next system.
> 
> My work-around, incidentally, involves creating another pair of
> staves with a different VerticalAxisGroup.remove-layer value, and
> changing \instScorePlan to use the first pair up to and including the
> trills, and the replacement pair thereafter.  Not very elegant, and
> if there were many trill passages it would quickly become unwieldy in
> the extreme.
> 
> Can anyone figure out why these spare trills are appearing, and how
> one can get rid of them reasonably simply?
>  
> David
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> \version "2.21.2"
> 
> instOne = \relative {
>   a'1 | a | a |
>   a1 \startTrillSpan | a1 \stopTrillSpan |
>   a | a | a | a | a | a | a |
> }
> 
> instTwo = \relative {
>   f'1 | f | f |
>   f2 \startTrillSpan f2 \startTrillSpan | f1 \stopTrillSpan |
>   f | f | f | f | f | f | f |
> }
> 
> targetStaff = #(define-scheme-function (ctx) (string?)
>   #{
>     \set Staff.keepAliveInterfaces = #'()
>     \context Staff = #ctx { \unset Staff.keepAliveInterfaces }
>   #})
> 
> instScorePlan = {
>   \targetStaff clarinetI s1*4
>   \targetStaff bothClarinets s1*3
>   \break s1*5 \break s1*5
> }
> 
> \score {
>     \new StaffGroup \with {
>     \consists "Keep_alive_together_engraver" }
>   <<
>     \new Staff = bothClarinets \with {
>       \RemoveAllEmptyStaves
>       \override VerticalAxisGroup.remove-layer = 40 }
>     << \partCombine \instOne \instTwo \instScorePlan >>
>     %% Clarinets on 2 staves:
>     \new Staff = clarinetI \with {
>       \RemoveAllEmptyStaves
>       \override VerticalAxisGroup.remove-layer = 20 }
>     << \instOne \instScorePlan >>
>     \new Staff = clarinetII \with {
>       \RemoveAllEmptyStaves
>       \override VerticalAxisGroup.remove-layer = 20 }
>      << \instTwo \instScorePlan >>
>   >>
> }
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>