Re: Color one SystemStartBrace

[David Nalesnik]

On Wed, Mar 13, 2019 at 4:27 PM David Nalesnik <address@hidden> wrote:
>
> On Wed, Mar 13, 2019 at 3:44 PM Urs Liska <address@hidden> wrote:
> >
> >
> > Am 13.03.19 um 19:47 schrieb David Nalesnik:
> > > On Wed, Mar 13, 2019 at 1:44 PM Aaron Hill <address@hidden> wrote:
> > >> On 2019-03-13 11:41 am, Aaron Hill wrote:
> > >>> On 2019-03-13 10:53 am, Urs Liska wrote:
> > >>>> Hi all,
> > >>>>
> > >>>> is it possible to get hold of a single SystemStartBrace/Bar/Bracket to
> > >>>> color it?
> > >>>>
> > >>>> \layout {
> > >>>>    \context {
> > >>>>      \Score
> > >>>>      \override SystemStartBrace.color = #red
> > >>>>    }
> > >>>> }
> > >>>>
> > >>>> works but
> > >>>>
> > >>>> (\once) \override Score.SystemStartBrace.color = #red
> > >>>>
> > >>>> somewhere in the input doesn't have any effect.
> > >>>>
> > >>>> Any suggestions?
> > >>> I think it's StaffGroup (or other appropriate container) that you
> > >>> want, not Score:
> > >>>
> > >>> %%%%
> > >>> \version "2.19.82"
> > >>>
> > >>> \new StaffGroup <<
> > >>>    \new Staff { \override StaffGroup.SystemStartBracket.color = #red b'1
> > >>> }
> > >>>    \new Staff { b'1 }
> > >>> %%%%
> > >> Oops, Score works too:
> > >>
> > >> %%%%
> > >> \version "2.19.82"
> > >>
> > >> \score { <<
> > >>     \new Staff { \override Score.SystemStartBar.color = #red b'1 }
> > >>     \new Staff { b'1 }
> > >>>> }
> > >> %%%%
> > >>
> > >> -- Aaron Hill
> > > This will color start bars on successive lines, too.
> > >
> > > Try:
> > >
> > > \version "2.19.82"
> > >
> > > one = \relative c' {
> > >    \alterBroken color #(list red blue black) StaffGroup.SystemStartBracket
> > >    a1 \break
> > >    a \break
> > >    a
> > > }
> > >
> > > two = \relative c' {
> > >    c c c
> > > }
> > >
> > > \new StaffGroup <<
> > >    \new Staff \one
> > >    \new Staff \two
> > > HTH,
> > > David
> >
> > Well, I *could* make that work in my case by placing that command at the
> > beginning of the score and use a list with all elements black and only
> > the last one in the highlighting color.
> >
> > But actually I would prefer having something that I can insert in the
> > input file right where it happens. Like not saying "color the fifth
> > system from here (the start)" but rather "color the next system".
> >
> > Urs
>
> You're not going to be able to do it simply, any more than you can
> introduce overrides of individual pieces of a broken slur once it's
> begun.  The starting bars are all clones of the first object.
>
> The only way I can suggest is to collect all the grobs on the system
> in question using the 'all-elements property (you can do this through
> a grob on the system in question), locate the target grob, and set its
> 'color property.
>
> DN

Like this:

\version "2.19.82"

#(define drop-in-on-spanner
   (lambda (grob)
     (let* ((elts (ly:grob-array->list (ly:grob-object (ly:grob-system
grob) 'all-elements)))
            (ssb (filter (lambda (e) (grob::has-interface e
'system-start-delimiter-interface))
                         elts)))
       (set! (ly:grob-property (car ssb) 'color) red))))

\new StaffGroup <<
  \new Staff {
    c1 \break
    \once \override NoteHead.after-line-breaking = #drop-in-on-spanner
    c1 \break
    c1 \break
  }
  \new Staff {
    c1
    c1
    c1
  }
>>