Force TextScript to staff-padding / optional \textLengthOn

[Urs Liska]

Hi,

I was struggling with this earlier, but suggestions from the list didn't help me and I had to postpone the issue. Now I've got to resolve it and while I make progress I don't seem to be able to get to the goal line :-(

I am trying to create a text command that prints items at a specific distance from the staff (in order to have multiple items on the same baseline). The behaviour of staff-padding is good enough for me, that is if one of the items is forced to be farther away to prevent collisions with the music I'm OK with adjusting the staff-padding for *all* items.

My problem is that the created markup should push other items to the right rather have them stack vertically as is the standard behaviour of TextScript - but only if there actually *is* such an item. Using \textLengthOn always pushes the next note column to the right, even when that doesn't have a text attached.

I found a solution using extra-spacing-width (but not extra-spacing-height) together with unsetting outside-staff-priority and wrapping all of this in an event-function:

\version "2.19.82"

#(define (create-foo text)
   #{
     -\tweak extra-spacing-width #(cons -0.0 .8)
     -\tweak outside-staff-priority ##f
     -\tweak staff-padding 3
     -\markup #text
   #})

this =
#(define-event-function ()()
   (create-foo "thisis."))

that =
#(define-event-function ()()
   (create-foo "thatis."))

\relative {
  e''16 \this [ f e \that d \this ]
}

In the attached 'correct.png' you can see that the *second* item "thatis." correctly pushes the next note in order to avoid the collision (the little white space comes from the .8 value to extra-spacing-width) while the first "thisis." leaves the second note alone.

However, I don't actually use a literal value for staff-padding but a callback function that modifies the staff-padding according to the direction. And as soon as staff-padding is set to that (any) callback function the behaviour is again like using \textLengthOn, as can be seen in the attached 'wrong.png' where the second note is wrongly pushed to the right:

\version "2.19.82"

#(define (calc-staff-padding grob)
   "Calculate the staff-padding value of a grob.
    This has to be done in a callback since it seems to be
    the only solution to both align texts to the baseline
    (using staff-padding) *and* to adjust upper and lower
    padding. See
    http://lists.gnu.org/archive/html/lilypond-user/2018-10/msg00267.html"
   (let ((dir (ly:grob-property grob 'direction))
         (staff-padding 4) ; in the real project this is loaded from options
         )
     (if (> dir 0)
         staff-padding
         ; NOTE: It is somewhat arbitrary to have lower texts
         ; pad by exactly 1 staff space more than above
         ; TODO: Calculate by creating a "Tq" markup and measuring its Y-extent
         (+ 1 staff-padding))))

#(define (create-foo text)
   #{
     -\tweak extra-spacing-width #(cons -0.0 .8)
     -\tweak outside-staff-priority ##f
     -\tweak staff-padding #calc-staff-padding
     -\markup #text
   #})

this =
#(define-event-function ()()
   (create-foo "thisis."))

that =
#(define-event-function ()()
   (create-foo "thatis."))

\relative {
  e''16 \this [ f e \that d \this ]
}

Can anyone explain why the TextScript is behaving differently when staff-padding is tweaked to a literal or to a callback? And - more importantly - how I can achieve my goal?

Thanks
Urs

correct.png
Description: PNG image

wrong.png
Description: PNG image