RE: Pedal cautionary continuations and other bracket decorations

[Andrew Bernard]

Drat. I can't get anything right today. Yes that's a personal scheme library
for formatting diagnostic print output. I try to purge this stuff before
posting but I have failed miserably. Below is the public MWE I meant to
send.

Andrew



-----Original Message-----
From: Simon Albrecht [mailto:address@hidden 
Sent: Saturday, 12 November 2016 9:05 PM
To: Andrew Bernard <address@hidden>; address@hidden
Subject: Re: Pedal cautionary continuations and other bracket decorations

Hi Andrew,


On 12.11.2016 04:19, Andrew Bernard wrote:
>
> \include "scheme.ily"
>

That seems to be a library file of your own, isn’t it?

> #(use-modules (srfi srfi-1))
>

You needn’t explicitly load that one, IIRC it’s available by default in
LilyPond.

Best, Simon

== snip

\version "2.19.50"

#(define (make-arrow-path arrow-length arrowhead-height arrowhead-width)
   "Arrow with triangular arrowhead."
   (list
    'moveto 0 0
    'lineto arrow-length 0
    'lineto arrow-length (/ arrowhead-width 2)
    'lineto (+ arrow-length arrowhead-height) 0
    'lineto arrow-length (- (/ arrowhead-width 2))
    'lineto arrow-length 0
    'closepath
    ))

pedalWithArrowsAndText =
\override Score.PianoPedalBracket.after-line-breaking =
#(lambda (grob)

   ;; function to modify the individual grob part
   (define add-decorations
     (lambda (g list-length)
       (let* (
               ;; unpack the argument
               (index (car g))
               (grobber (cadr g))
               (last (= index list-length))

               ;; Get the default-stencil and its x-dimension and x-length.
               (stil (ly:piano-pedal-bracket::print grobber))
               (stil-x-extent (ly:stencil-extent stil X))
               (stil-x-length (interval-length stil-x-extent))


               ;; make arrow for the rhs end
               (thickness 0.1)
               (arrowhead-height 1.0)
               (arrowhead-width 1.0)
               (arrow-length 1.0)
               (arrow (make-path-stencil (make-arrow-path arrow-length
arrowhead-height arrowhead-width) thickness 1 1 #t))
               (new-stil (if (not last)
                             (ly:stencil-combine-at-edge stil X RIGHT arrow
-2)
                             stil))

               ;; make text for the lhs end
               (text-stil
                (grob-interpret-markup grobber
                  (markup
                   #:line
                   (#:abs-fontsize
                    6
                    (#:sans
                     (#:upright
                      (#:whiteout (#:box (#:pad-markup 0.3 "½ ped")))))))))

               (new-stil (ly:stencil-stack new-stil X LEFT text-stil -6)))

         (ly:grob-set-property! grobber 'stencil new-stil))))

   (let* (
           (stil (ly:piano-pedal-bracket::print grob))
           (orig (ly:grob-original grob))
           (pieces (if (ly:grob? orig)
                       (ly:spanner-broken-into orig)
                       '()))
           (pieces-indexed-list (zip (iota (length pieces) 1) pieces))
           (pieces-length (length pieces)))

     ;; We want arrows on all segments but the last, and text on all
segments, so
     ;; we have to pass some notion of list index to the function doing the
     ;; decorating. Hence the ziplist combining grob segment and index in
pairs.

     (let loop ((x 1)
                (count 0))
       (if (< count pieces-length)
           (begin
            (add-decorations (list-ref pieces-indexed-list count)
pieces-length)
            (loop x (+ count 1))
            )))
     #t
     ))

%===========================================================================
================

treble = {
  \clef treble
  \time 4/4
  c'4 c' c' c'
  c' c' c' c'
}

bass = {
  \clef bass
  \time 4/4

  c4
  \pedalWithArrowsAndText
  c\sustainOn c c
  c c c c
  \break
  c c c c
  \break
  c c c^\sustainOff\sustainOn c
  \break
  c c c c
  \break
  c c\sustainOff\sustainOn c c
  \break
  c c c c
  \break
  c c c c\sustainOff

}

\score {

  \new PianoStaff
  <<
    \new Staff = "treble"  { \treble }
    \new Staff = "bass" { \bass }
  >>

  \layout {
    \context {
      \Score
      pedalSustainStyle = #'bracket
    }
  }
}
== snip