generating a few isolated notes

[Xavier Noria]

I would like to generate this swing equality

     https://musescore.org/sites/musescore.org/files/swing_0.jpg

to have it printed in a t-shirt.

I am trying something like this (cargo culting online code) but
can't get spacing around  the equal sign right. I have read the
documentation about horizontal spacing but all seems to
assume the markup shouldn't affect distance between notes.

Can anybody help?


\version "2.18.2"

\layout {
  pagenumber = no
  #(layout-set-staff-size 26)

  \context {
    \Staff
    \remove "Time_signature_engraver"
    \remove "Clef_engraver"
    \remove "Bar_engraver"
  }
}

\header {
  tagline = ""
}

melody = \relative c''' {
  \override TextScript.extra-offset = #'(2 . 2)
  \stopStaff a,8 a8-\markup { \whiteout \pad-markup #0.5 "=" } \times 2/3 { a4 
a8 }
}

\score {
  { \melody }
}