Re: shorten a broken hairpin at a linebreak?

[Mike Solomon]

On Aug 31, 2011, at 5:30 PM, harm6 wrote:

> 
> 
> Mike Solomon-2 wrote:
>> 
>> Hmm...I thought that after-line-breaking would be called after the bounds
>> were set, but I was wrong.
>> 
>> Try:
>> 
>> #(define (has-interface? grob interface)
>> (member interface
>>         (assoc-get 'interfaces
>>                    (ly:grob-property grob 'meta))))
>> 
>> #(define (find-system grob)
>> (if (has-interface? grob 'system-interface)
>>     grob
>>     (find-system (ly:grob-parent grob X))))
>> 
>> #(define (first-musical-column grobl)
>> (if (not (eqv? #t (ly:grob-property (car grobl) 'non-musical)))
>>     (car grobl)
>>     (first-musical-column (cdr grobl))))
>> 
>> #(define (change-bound grob)
>> (let* ((system (find-system grob))
>>        (cols (ly:grob-array->list (ly:grob-object system 'columns)))
>>        (musical-column (first-musical-column (reverse cols))))
>>   (ly:spanner-set-bound! grob RIGHT musical-column)))
>> 
>> #(define (internal-my-callback grob)
>>  (let* (
>>         ;; have we been split?
>>         (orig (ly:grob-original grob))
>> 
>>         ;; if yes, get the split pieces (our siblings)
>>         (siblings (if (ly:grob? orig)
>>                       (ly:spanner-broken-into orig)
>>                       '())))
>> 
>>    (if (and (>= (length siblings) 2)
>>             (not (eq? (car (reverse siblings)) grob)))
>>      (change-bound grob))))
>> 
>> #(define (my-callback grob)
>> (internal-my-callback grob)
>> (ly:hairpin::print grob))
>> 
>> {
>> a1\break
>> \override Hairpin #'stencil = #my-callback
>> a\< \repeat unfold 31 { a } \break \key fis \major
>> \repeat unfold 32 { a } \break \key ees \major \repeat unfold 42 {a} a\p
>> }
>> 
>> It may result in oddities with other grobs that rely on spanner bounds,
>> but it should be tame in most situations.
>> 
>> Cheers,
>> MS
>> 
> 
> 
>    Hi Mike,
> 
>    now it works as expected, but I found another problem:
>    Using \> instead of \< looks like succeeding decrescendos and not one
> continuous one.
> 
>    One more question: Would it be possible to increase the control of the
> length of the hairpin?
>    Doing the following at the end of a hairpin allows some more control on
> the length of the hairpin. Not so for anywhere in the middle of it..
> 
>    \relative c' {
>      \override Hairpin #'stencil = #my-callback
>       c'1\> c1*5/8 s1*3/8
>       \break
>       \key cis\major
>      d2 e e1*7/8 s1*1/8\!
>    }
> 
>    Would any such increased / improved control be feasible in the context
> of the solution you developed so far?
> 
> 
>    Best,
>    Harm
> 

More control over the length is always achievable by overriding the stencil, as 
is the solution to the problem you pose above regarding the closing diminuendi.
Try:

#(define (has-interface? grob interface)
(member interface
        (assoc-get 'interfaces
                   (ly:grob-property grob 'meta))))

#(define (find-system grob)
(if (has-interface? grob 'system-interface)
    grob
    (find-system (ly:grob-parent grob X))))

#(define (first-musical-column grobl)
(if (not (eqv? #t (ly:grob-property (car grobl) 'non-musical)))
    (car grobl)
    (first-musical-column (cdr grobl))))

#(define (change-bound grob)
(let* ((system (find-system grob))
       (cols (ly:grob-array->list (ly:grob-object system 'columns)))
       (musical-column (first-musical-column (reverse cols))))
  (ly:spanner-set-bound! grob RIGHT musical-column)))

#(define (internal-my-callback grob fn1 fn2)
 (let* (
        ;; have we been split?
        (orig (ly:grob-original grob))

        ;; if yes, get the split pieces (our siblings)
        (siblings (if (ly:grob? orig)
                      (ly:spanner-broken-into orig)
                      '())))

   (if (and (>= (length siblings) 2)
            (not (eq? (car (reverse siblings)) grob)))
     (fn1 grob)
     (fn2 grob))))

#(define (change-ends grob)
  (let* ((st (ly:hairpin::print grob))
         (gd (ly:grob-property grob 'grow-direction))
         (w (ly:stencil-extent st X))
         (thick (* (ly:grob-property grob 'thickness) 
(ly:staff-symbol-line-thickness grob)))
         (h (ly:stencil-extent st Y))
         (ylu (if (eqv? gd RIGHT) (interval-center (cons (interval-center h) 
(cdr h))) (cdr h)))
         (yru (if (eqv? gd RIGHT) (cdr h) (interval-center (cons 
(interval-center h) (cdr h)))))
         (yld (if (eqv? gd RIGHT) (interval-center (cons (car h) 
(interval-center h))) (car h)))
         (yrd (if (eqv? gd RIGHT) (car h) (interval-center (cons (car h) 
(interval-center h))))))
    (ly:stencil-add
      (make-line-stencil thick (car w) ylu (cdr w) yru)
      (make-line-stencil thick (car w) yld (cdr w) yrd))))

#(define (my-callback grob)
  (internal-my-callback grob change-bound values)
  (if (eqv? LEFT (ly:grob-property grob 'grow-direction))
     (internal-my-callback grob change-ends ly:hairpin::print)
     (ly:hairpin::print grob)))

{
a1\break
\override Hairpin #'stencil = #my-callback
\override Hairpin #'bound-padding = #my-callback
a\> \repeat unfold 31 { a } \break \key fis \major
\repeat unfold 32 { a } \break \key ees \major \repeat unfold 42 {a} a\p
}

{
a1\break
\override Hairpin #'stencil = #my-callback
\override Hairpin #'bound-padding = #my-callback
a\< \repeat unfold 31 { a } \break \key fis \major
\repeat unfold 32 { a } \break \key ees \major \repeat unfold 42 {a} a\p
}