Re: Printing Chordnames as Roman Numbers

[Jean Abou Samra]

Le mercredi 01 mars 2023 à 09:54 +0100, Johan Smolinski a écrit :

I asked this in the facebook group, but was rdirected to this mailing list, so... Here I am. :)

How can I print chordnames as roman numbers relative to given key? For instance, in key of C (given by \key c \major), I want the chord c:7 printed as I7 while in key of F, I want c:7 printed as V7.

You could use a Scheme engraver.

Try this:

\version "2.24.1"

\layout {
  \context {
    \ChordNames
    \consists
      #(lambda (context)
         (let ((tonic #{ c #}))
           (make-engraver
            ((initialize engraver)
             (set! (ly:context-property context 'chordRootNamer)
                   (lambda (pitch capitalized)
                     (let ((degree (1+ (ly:pitch-notename (ly:pitch-diff pitch tonic)))))
                       (number-format 'roman-upper degree)))))
            (listeners
             ((key-change-event engraver event)
              (set! tonic (ly:event-property event 'tonic)))))))
  }
}

\chords {
  a1 b1:m c1 d2:sus4
  \key a \minor
  a1 b1:m c1 d2:sus4
}

HTH,

Jean

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