> I really like what you have done with this image:
> [image: image.png]
:-)
> It’s so helpful for illustrating reference point, horizontal extent,
> and vertical extent, and I could never have done it myself!
You most certainly could do that. Below is the LilyPond source code
(from file `Documentation/en/notation/changing-defaults.itely` as can
be found in the MR).
Werner
======================================================================
#(define-markup-command (point layout props x y xoff yoff)
(number? number? number? number?)
(interpret-markup
layout props
(make-overlay-markup
(list
(make-translate-markup
(cons x y)
(make-draw-circle-markup 0.4 0 #t))
(make-translate-markup
(cons (+ x xoff) (+ y yoff))
(make-concat-markup
(list "(" (number->string x) ", " (number->string y) ")")))))))
\markup \scale #'(0.8 . 0.8) {
\overlay {
\scale #'(18 . 16) \with-color #(x11-color "gray80")
\musicglyph "accidentals.flatflat.slash"
\override #'((filled . #f)
(thickness . 2))
\polygon #'((-9 . -10) (-9 . 29) (26 . 29) (26 . -10))
\translate #'(-15 . 0) \draw-line #'(47 . 0)
\translate #'(32 . 0) \arrow-head #X #RIGHT ##t
\translate #'(31 . -2) \italic x
\translate #'(0 . -15) \draw-line #'(0 . 50)
\translate #'(0 . 35) \arrow-head #Y #UP ##t
\translate #'(-2 . 34) \italic y
\point #0 #0 #0.5 #0.8
\point #-9 #-10 #0.5 #0.8
\point #26 #29 #-3 #1
\translate #'(-10.5 . 19) \draw-line #'(0 . 10)
\translate #'(-10.5 . 29) \arrow-head #Y #UP ##t
\translate #'(-18 . 10) \rotate #90 \italic "vertical extent"
\translate #'(-10.5 . 2.5) \draw-line #'(0 . -12.5)
\translate #'(-10.5 . -10) \arrow-head #Y #DOWN ##t
\translate #'(-0.5 . -12) \draw-line #'(-8.5 . 0)
\translate #'(-9 . -12) \arrow-head #X #LEFT ##t
\translate #'(9 . -12.5) \center-align \italic "horizontal extent"
\translate #'(18 . -12) \draw-line #'(8 . 0)
\translate #'(26 . -12) \arrow-head #X #RIGHT ##t
}
}
