Re: Coloring Ledger Lines

[David Nalesnik]

Hi,

On Sun, Mar 8, 2015 at 9:35 AM, Pierre Perol-Schneider <address@hidden> wrote:

No clue.

I just know that some grobs, like 'StaffSymbol' too, need to be reverted that way :

Consider this snippet:

\version "2.19.16"

#(define ledgerInfo

   (lambda (grob)

     (let* ((refp (ly:grob-system grob))

            (all (ly:grob-array->list (ly:grob-object refp 'all-elements)))

            (ledgers (filter (lambda (l)

                               (grob::has-interface l 'ledger-line-spanner-interface))

                             all)))

       (display ledgers) (newline))))

\relative c' {

  \override Staff.StaffSymbol.after-line-breaking =

   #(lambda (grob) (display grob) (newline))

  \override Staff.LedgerLineSpanner.after-line-breaking = #ledgerInfo

  \override NoteHead.color = #grey

  \override Stem.color = #grey

  \override Staff.LedgerLineSpanner.color = #grey

  \override Staff.StaffSymbol.color = #grey

  a4 a a a

  %\stopStaff

  %\startStaff

  \revert NoteHead.color

  \revert Stem.color

  \revert Staff.LedgerLineSpanner.color

  \revert Staff.StaffSymbol.color

  %\startStaff

  a a a a 

}

%%%%%%%%

Notice that with the \stopStaff and \startStaff commented out, there is a single StaffSymbol grob in the example.  It makes sense that any override will apply to the whole object.  When \stopStaff and \startStaff are in effect, a second StaffSymbol grob is created, and it can of course take a new override or revert.

Very surprisingly, there is only a single LedgerLineSpanner per StaffSymbol object!  This means that any override of LedgerLineSpanner will affect all of them.

--David