%2) On dessine les points

%------------------------------------------------------

% ici on défini les points qu'on fait sur le piano
#(define (make-dot-list l1)
   (reduce
    ly:stencil-add
    empty-stencil
    (map
     (lambda (dl) (make-dot (ly:pitch-notename dl)))
     l1)))

% ici on défini i on fait des ronds noirs ou blancs
#(define (make-dot key)
   (ly:stencil-in-color
    (ly:stencil-translate
     (make-circle-stencil 0.25 0.1 #f)
     (key-to-pos key))
    (car (key-to-color key))
    (cadr (key-to-color key))
    (caddr (key-to-color key))))  % pour les ronds noirs


% ici on défini les couleurs R V B associés à chaque notes
#(define (key-to-color key )
   (let ((keycolor (caddr (assq key Color-KEY-LIST))))
     (if (not keycolor)
         (ly:error (_ "Color diagram error - unkown note '~a'") key)
         (caddr (assq key Color-KEY-LIST)))))

% ici on défini les positions des points du clavier en y
#(define (key-to-pos key )
   (let ((keypos (assq key KEY-POS-LIST)))
     (if (not keypos)
         (ly:error (_ "keyboard diagram error - unkown note '~a'") key)
         (caddr (assq key KEY-POS-LIST)))))

#(define KEY-POS-LIST
   '(
      (-8   .  '( 0  . 0))
      (-7   .  '( 0  . 1))
      (-6   .  '( 0  . 2))
      (-5   .  '( 0  . 3))
      (-4   .  '( 1  . 0))
      (-3   .  '( 1  . 1))
      (-2   .  '( 1  . 2))
      (-1   .  '( 1  . 3))
      (0   .  '( 0  . 0))
      (1   .  '( 0  . 1))
      (2   .  '( 0  . 2))
      (3   .  '( 0  . 3))
      (4   .  '( 1  . 0))
      (5   .  '( 1  . 1))
      (6   .  '( 1  . 2))
      (7   .  '( 1  . 3))
      (8   .  '( 0.71  . 1))
      (9   .  '( 0.71  . 1))
      (10  .  '( 0.71  . 1))
      (11  .  '( 0.71  . 1))
      (12  .  '( 0.71  . 1))
      (13  .  '( 0.71  . 1))
      (14  .  '( 0.71  . 1))
      (15  .  '( 0.71  . 1))
      (16  .  '( 0.71  . 1))
      (17  .  '( 0.71  . 1))
      (18  .  '( 0.71  . 1))
      (19  .  '( 0.71  . 1))
      (20  .  '( 0.71  . 1))
      (21  .  '( 0.71  . 1))
      (22  .  '( 0.71  . 1))
      (23  .  '( 0.71  . 1))
      ))


#(define Color-KEY-LIST
   '(
      (-11 .  '( 0.71     1    1))
      (-10 .  '( 0.71     1    1))
      (-9  .  '( 0.71     1    1))
      (-8  .  '( 0.71     1    1))
      (-7  .  '( 0.71     1    1))
      (-6  .  '( 0.71   0.2   1))
      (-5  .  '( 0.71   0.2   1))
      (-4  .  '( 0.71   0.2   1))
      (-3  .  '( 0.71   0.2   1))
      (-2  .  '( 0.71   0.2   1))
      (-1  .  '( 0.71   0.2   1))
      (0   .  '( 0.71     1    1))
      (1   .  '( 0.71     1    1))
      (2   .  '( 0.71     1    1))
      (3   .  '( 0.71     1    1))
      (4   .  '( 0.71     1    1))
      (5   .  '( 0.71   0.2   1))
      (6   .  '( 0.71   0.2   1))
      (7   .  '( 0.71   0.2   1))
      (8   .  '( 0.71   0.2   1))
      (9   .  '( 0.71   0.2   1))
      (10  .  '( 0.71   0.2   1))
      (11  .  '( 0.71   0.2   1))
      (12  .  '( 0.71   0.2   1))
      (13  .  '( 0.71   0.2   1))
      (14  .  '( 0.71   0.2   1))
      (15  .  '( 0.71   0.2   1))
      (16  .  '( 0.71   0.2   1))
      (17  .  '( 0.71   0.2   1))
      (18  .  '( 0.71   0.2   1))
      (19  .  '( 0.71   0.2   1))
      (20  .  '( 0.71   0.2   1))
      (21  .  '( 0.71   0.2   1))
      (22  .  '( 0.71   0.2   1))
      (23  .  '( 0.71   0.2   1))
      ))


#(define (engrave-back)
   (map (lambda (p) (ly:stencil-in-color
                     (ly:stencil-translate
                      (make-circle-stencil 0.4 0 #f)
                      p)
                     0 0 0))
     '((0 . 0)
       (0 . 1)
       (0 . 2)
       (0 . 3)
       (1 . 0)
       (1 . 1)
       (1 . 2)
       (1 . 3)))
   )  % pour les ronds noirs




#(define-markup-command (complete layout props the-chord)
   (ly:music?)
   (ly:stencil-scale
    (reduce
     ly:stencil-add
     empty-stencil
     (cons
      (make-dot-list (map (lambda (m) (ly:music-property m 'pitch))
                       (extract-named-music the-chord 'NoteEvent)))
      (engrave-back)))
    1 1))


diag=
#(define-music-function (parser location music)
   (ly:music?)
   (music-map
    (lambda (m)
      (if (music-is-of-type? m 'event-chord)
          #{ <>^\markup \complete #m $m #}
          m))
    music))


global = {
  \time 4/4
  \key a \minor
  \tempo 4=80
}

% ici on écrit la parto
melody = \relative c'' {
  \global

  \bar ".|:"a8 a16 b a g e g a8 g16 a c b a g d'8 d c16 b a g c d b8. b16 c b |
  a8 a16 b a g e g a8 g16 a c b a g d'8 d c16 b a g c d b8. b16 c d  \break|
  e8 e d16 c b a d8 c16 d e c a b c8 b16 a d8  c16 b a b c d b8   c16 d|
  e8 e d16 c b a d8 c16 d e c a b | c8  b16 a d c d e b8 a16 g a r8 r16|
  \bar ":|."
}


chordNames =
\chordmode  {
  \global

  c8 a4:m5 g8:5 a8:m5 a:m5 a:m5 a:m5 d:m5 d4:m7 d8:m7 f:5 g4:5 e8:m/b
  a8:m5 a4:m5 g8:5 a8:m5 a:m5 a:m5 a:m5 d:m5 d4:m7 d8:m7 f:5 g4:5 g8:5
  a8:m5 a4:m5 a8:m5 g8:5 a4:m5 a8:m5 f:5 f:5 d4:m7  f:5 g8:5 g8:5
  c4:5  c4:5 d8:m7 d4:m7 d8:m7 f4:5 g4:5 f8:5 g8:5 a,4:m }


\score {
  <<
    \new ChordNames \with { \consists "Text_engraver" } \diag \chordNames
    \new Staff { \melody }
  >>
  \layout {}
  \midi { }
}