I was able to get something bolder by using the uppercase delta glyph. But it isn't perfect.
-Greg
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\version "2.22"
embiggenChordNames = #(define-scheme-function (size) (number?)
#{ \with {
chordNameFunction = #(lambda (in-pitches bass inversion context)
(define exemptions (list musicglyph-markup))
(define (helper mu)
(if (list? mu)
(if (memq (car mu) exemptions)
(markup (#:fontsize (- size) mu))
(map helper mu))
mu))
(let ((orig (ignatzek-chord-names in-pitches bass inversion context)))
(markup (#:fontsize size (helper orig)))))
} #} )
\paper {
ragged-last = ##f
}
\layout {
indent = #0
\context { \ChordNames \embiggenChordNames #2.5 }
\override ChordName #'font-name = #"Open Sans Soft Cd SemiBd"
\override Staff.BarLine.hair-thickness = #4
\override Staff.BarLine.thick-thickness = #8
}
IntroChords = \chordmode {
\time 6/8
\set majorSevenSymbol = \markup { Δ }
\set minorChordModifier = \markup { − }
a2.:m7 c2.:maj7 des2. f2.:dim
a2.:m6 e2.:aug a2.:m eis2.:7
}
<<
\new ChordNames \with {
\override BarLine.bar-extent = #'(-1 . 3.5)
\consists "Bar_engraver"
}
\IntroChords
>>
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