problem with installed font when set-global-staff-size is changed

[Jonathan Scholbach]

Hi!

I would like to use the Garamond font for all the text in my sheet
(header, lyrics, markup). I downloaded the EBGaramond from
http://www.georgduffner.at/ebgaramond/download.html and put all the
.otf-files into the directory

lilypond/usr/share/lilypond/current/fonts/otf

Nearly everything works fine, but Lilypond seems to have problems with
scaling, as my ME shows. The lyrics between the staves are not printed
in Garamond font when the global-staff-size is changed.

I don't understand the way lilypond deals with fonts. Can you please
help me?

Thank you,

Jonathan

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\version "2.19.22"

sopVoice = \relative c'' { c4 c c c c c2 c4 c c c c}
sopLyrix = \lyricmode { This is (not) Ga -- ra -- mond: "1" a A q Q }

\paper {
  #(define fonts
     (make-pango-font-tree "EBGaramond"
                           "Nimbus Sans"
                           "Luxi Mono"
                           (/ staff-height pt 17)
     )
   )
}

%this prints Garamond
\score {
 % \layout { #(layout-set-staff-size 20) }
  \new Staff <<
    \new Voice = "sop" {  \sopVoice }
    \new Lyrics \lyricsto "sop" { \sopLyrix }
     >>
}
What .
%this fails to print Garamond
\score {
  \layout { #(layout-set-staff-size 21) }
  \new Staff <<
    \new Voice = "sop" { \sopVoice }
    \new Lyrics \lyricsto "sop" { \sopLyrix }
     >>
}

%this prints Garamond as well
\markup { \override #'(font-name . "EBGaramond") \fontsize #6 "This
prints EBGaramond as well: 1 a A q Q"}