Associate drumnotes with custom NoteHead stencils

This snippet shows how to associate drum-notenames with custom stencils which will automagically be used as the standard notehead for the assigned drumnote.

In your ly-code you need to have these stencils defined. A simple example can be found in this snippet. Additionally there are two more examples used in this snippet for demonstration.

The second step is to customise the list (stencil-mapping) where the drumnotes are assigned to new stencils. List only those drumnotes you want to have displayed with your own notehead and be sure to put the full notename, not its abbreviation, e.g. 'bassdrum will work, 'bd won't.

Off course this will also work with custom drumstyle-Tables and, if used, with custom drum-notenames.

\version "2.24"

%% http://lsr.di.unimi.it/LSR/Item?id=617

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Here are the stencils defined %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

#(define (circSlash grob)
   (let* ((line-thickness (ly:staff-symbol-line-thickness grob))
          (width (+ line-thickness 1))
          (stem-thickness (* line-thickness 1.3))
          (radius (/ (- width stem-thickness) 2)))
     (ly:make-stencil (list 'embedded-ps
                            (string-append "
          /line-thickness " (number->string line-thickness) " def
          /stem-thickness " (number->string stem-thickness) " def
          /radius " (number->string radius) " def
          /width " (number->string width) " def
          /half-width width 2 div def
          /x0 half-width def
          /y0 0 def
          /x1 width stem-thickness 2 div sub def
          /y1 half-width stem-thickness 2 div sub def
          /x2 stem-thickness 2 div def
          /y2 half-width neg stem-thickness 2 div add def

          gsave
          currentpoint translate
          stem-thickness setlinewidth
          newpath
          x0 y0 radius 0 360 arc
          stroke

          newpath
          1 setlinecap
          x1 y1 moveto
          x2 y2 lineto
          stroke
          grestore"))
                      (cons 0 width)
                      (cons 0 0))))

#(define plus
   (ly:make-stencil (list 'embedded-ps
      "gsave
       currentpoint translate
       newpath
       -0.05 0 moveto
       1.05 0 lineto
       closepath
       0.2 setlinewidth
       stroke
       
       newpath
       0.5 -0.45 moveto
       0.5 0.45 lineto
       closepath
       0.2 setlinewidth
       stroke
       grestore" )
      (cons -0.15 1.15)
      (cons 0 0)))
      
parallelogram =
  #(ly:make-stencil (list 'embedded-ps
    "gsave
      currentpoint translate
      newpath
      0 0.25 moveto
      1.3125 0.75 lineto
      1.3125 -0.25 lineto
      0 -0.75 lineto
      closepath
      fill
      grestore" )
    (cons 0 1.3125)
    (cons 0 0))

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Here ends the stencil definition. %%%
%%%   The actual function follows.    %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
#(define stencil-mapping
   (list
    (cons 'bassdrum parallelogram)
    (cons 'hightom circSlash)
    (cons 'lowtom plus)
    (cons 'snare circSlash)))

#(define (mod-notehead music)
   (if (eq? (ly:music-property music 'name) 'EventChord)
       (let ((n (length (ly:music-property music 'elements))))
         (do ((i 0 (1+ i))) ((= i n))
           (let* ((ne (list-ref (ly:music-property music 'elements) i))
                  (dt (ly:music-property ne 'drum-type))
                  (st (assoc dt stencil-mapping)))
             (if st
                 (ly:music-set-property! ne 'tweaks (list (cons 'stencil (cdr st)))))))))
   music)

customHeads =
#(define-music-function (music) (ly:music?)
   (music-map (lambda (x) (mod-notehead x)) music))

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Below is a short sample. %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
\new DrumVoice \drummode {
  \customHeads { <sn hh bd>4 tomh toml <toml sn> }
}