Re: Tie settings question

[David Nalesnik]

Hi Karol,

On Sat, Oct 22, 2016 at 7:33 AM, Karol Majewski <address@hidden> wrote:
> Now I try to change Flag.Y-extent value in chords to: \override Flag.Y-extent 
> = #'(4 . 0)
>
> Got this, but it doesn't work. What am I doing wrong?
>
> evenTies =
> #(lambda
>   (grob)
>   (let
>     ((ties
>         (ly:grob-array->list
>           (ly:grob-object grob 'ties))))
>     (if
>       (>
>         (length ties) 1)

(1) Use begin to group multiple expressions in the if clause

(2) As the log will tell you, "flag" is not defined.  I assume you
arrived at this because of Harm's usage of "tie"
below.  He's creating a local variable to refer to Tie grobs which
he's already obtained, not relying on some existing correspondence
between "tie" and a Tie grob..  (As such, he could have replaced 'tie'
with another identifier, like "my-variable")

You need "flag" to point to an actual Flag, which requires following
pointers from your starting object -- a TieColumn -- to Tie.  In the
code below, you can see how I might do it.

(3) 'Y-extent takes a number pair.

>       ((ly:grob-set-property! flag 'Y-extent 4 0)
>       (for-each
>         (lambda
>           (tie)
>           (ly:grob-set-nested-property! tie '(details skyline-padding) 5)) 
> ties)))))

%%%%%%%%%%%%%%%

evenTies =
#(lambda
  (grob)
  (let* ((ties (ly:grob-array->list (ly:grob-object grob 'ties)))
         (notehead (ly:spanner-bound (car ties) LEFT))
         (stem (ly:grob-object notehead 'stem))
         (flag (ly:grob-object stem 'flag)))
    (if (> (length ties) 1)
        (begin
         (ly:grob-set-property! flag 'Y-extent (cons 4 0))
         (for-each
          (lambda (tie)
            (ly:grob-set-nested-property! tie '(details skyline-padding) 5))
          ties)))))

\layout {
  \context {
    \Score
    \override TieColumn.before-line-breaking = #evenTies
  }
}


\score {

  \relative c' {
    <c e g c e>8~
    <c e g c e>4
    c8~ c4.
  }
}

%%%%%%%%%%%%%%%%

Hope this helps,
David