\version "2.13.2"

#(define-markup-command (pitchedtexttrill layout props alter) (number?)
    (interpret-markup layout props
      (markup #:lower 1 
              ;#:halign -1.4 
              #:musicglyph "scripts.trill" 
              #:hspace -0.5 
              #:fontsize -1
              #:musicglyph (assoc-get alter standard-alteration-glyph-name-alist "" ))))

\markuplines \justified-lines {pitched trill as a simple markup}
\relative c' { c^\markup{\pitchedtexttrill #SHARP }}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

flatTrillI = #(let ((m (make-music 'ArticulationEvent 'articulation-type "trill")))
   (ly:music-set-property! m 'tweaks
     (acons 'stencil (make-pitchedtexttrill-markup FLAT)
       (ly:music-property m 'tweaks)))
  m)

\markuplines \justified-lines {pitched trill as an articulation with stencil tweak (every second note)}
\relative c' { 
  c4\flatTrillI c-\flatTrillI c4^\flatTrillI c_\flatTrillI
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

pitchedtrill = #(define-music-function (parser location alter) (number?)
  (let ((m (make-music 'ArticulationEvent
                      'articulation-type "trill")))
   (ly:music-set-property! m 'tweaks
     (acons 'stencil (make-pitchedtexttrill-markup alter)
       (ly:music-property m 'tweaks)))
m))

flatTrill = -\pitchedtrill #FLAT
sharpTrill = -\pitchedtrill #SHARP

\markuplines \justified-lines {pitched trill as an articulation with stencil tweak as music-function}
\relative c' {
  c4\pitchedtrill #FLAT c4-\pitchedtrill #FLAT  c4\flatTrill c4\sharpTrill
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

flatTrillI = -\tweak #'stencil #(make-pitchedtexttrill-markup FLAT ) \trill
sharpTrillI = -\tweak #'stencil #(make-pitchedtexttrill-markup SHARP ) \trill


\markuplines \justified-lines {Tweaking a trill stencil using a simple definition, stencil set to (make-pitchedtexttrill-markup XXX)}
\relative c' {
  c4\flatTrillI c4\sharpTrillI c4-\flatTrillI c4-\sharpTrillI 
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% 	(stencil . ,ly:text-interface::print)
% 	(text . ,(make-musicglyph-markup "scripts.rcomma"))

flatTrillII = -\tweak #'stencil #ly:text-interface::print -\tweak #'text #(make-pitchedtexttrill-markup FLAT ) \trill
sharpTrillII = -\tweak #'stencil #ly:text-interface::print -\tweak #'text #(make-pitchedtexttrill-markup SHARP ) \trill
pitchedtrillII = #(define-music-function (parser location alter) (number?)
  (let ((m (make-music 'ArticulationEvent
                      'articulation-type "trill")))
   (ly:music-set-property! m 'tweaks
     (acons 'stencil ly:text-interface::print (acons 'text (make-pitchedtexttrill-markup alter)
       (ly:music-property m 'tweaks))))
m))



\markuplines \justified-lines { The same, using the text-interface::print stencil and the text property; Usine a music-function only works with - prepended }
\relative c' {
  c4\flatTrillII c4\sharpTrillII c4-\flatTrillII c4-\sharpTrillII
  c4\pitchedtrillII #FLAT c4-\pitchedtrillII #FLAT
  c4\pitchedtrillII #NATURAL c4-\pitchedtrillII #NATURAL
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

\markuplines \justified-lines { Tweaking trill spanners. Default text, but extra-offset }
\relative c' {
  c4-\tweak #'extra-offset #'(2 . -5) \startTrillSpan c c c\stopTrillSpan
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

% tWF = -\tweak #'bound-details #'left #'text = \markup{\pitchedtexttrill #FLAT } 
%       -\tweak #'extra-offset = #'(0 . -0.5) \startTrillSpan

trillWithFlat = {
        \once \override TrillSpanner #'bound-details #'left #'text = \markup{\pitchedtexttrill #FLAT }
        \once \override TrillSpanner #'extra-offset = #'(0 . -0.5)
}
trillWithNatural =
{
        \once \override TrillSpanner #'bound-details #'left #'text = \markup{\pitchedtexttrill #NATURAL }
        \once \override TrillSpanner #'extra-offset = #'(0 . -0.5)
}
trillWithSharp =
{
        \once \override TrillSpanner #'bound-details #'left #'text = \markup{\pitchedtexttrill #SHARP }
        \once \override TrillSpanner #'extra-offset = #'(0 . -0.5)
}

\markuplines \justified-lines { Changing text of trill spanner using "\override" before the note, text created by "\markup{\pitchedtexttrill #XXX}" }
\relative c' {
  c4\startTrillSpan c4 c4 c4\stopTrillSpan |
  \trillWithFlat c4\startTrillSpan c4 c4 c4\stopTrillSpan |
  \trillWithSharp c4\startTrillSpan c4 c4 c4\stopTrillSpan |
  \trillWithNatural c4\startTrillSpan c4 c4 c4\stopTrillSpan |
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

\markuplines \justified-lines {Trying to set the values using tweaks for the spanner. Apparently, tweaking the bound-details -> left -> text is not so easy!!!}

startSharpTrillSpan = -\tweak #'extra-offset #'(0 . -0.5) 
                      -\tweak #'bound-details #'((left . ((text . ,(make-translate-scaled-markup
                                                      '(0.0 . -1.0) (make-pitchedtexttrill-markup SHARP )))))) \startTrillSpan
startFlatTrillSpan = -\tweak #'extra-offset #'(0 . -0.5) \startTrillSpan

\relative c' {
  c4\startSharpTrillSpan c4 c4 c4\stopTrillSpan |
  c4\startFlatTrillSpan c4 c4 c4\stopTrillSpan |
}


% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~