Re: How to determine if a font is a fallback font?

[Werner LEMBERG]

On my openSuSE GNU/Linux box, I get different results.

> Given font name: Emmentaler-13
> Determined font file: /usr/share/fonts/TTF/mplus-1c-medium.ttf
> Actual font in that file: mplus-1c-medium
> Given font is present: #f

  Given font name: Emmentaler-13
  Determined font file: 
/usr/local/share/lilypond/2.19.16/fonts/otf/emmentaler-13.otf
  Actual font in that file: Emmentaler-13
  Given font is present: 
#t/usr/local/share/lilypond/2.19.16/fonts/otf/emmentaler-13.otf
  Emmentaler-13

> Given font name: Alegreya
> Determined font file: /usr/share/fonts/TTF/mplus-1c-medium.ttf
> Actual font in that file: mplus-1c-medium
> Given font is present: #f

  Given font name: Alegreya
  Determined font file: /usr/share/fonts/truetype/Alegreya-Regular.ttf
  Actual font in that file: Alegreya-Regular
  Given font is present: #f/usr/share/fonts/truetype/Alegreya-Regular.ttf
  Alegreya-Regular

Note that `ly:ttf-ps-name' returns the font's *PostScript* name.  This
is *not* what fontconfig normally operates on (but see below).

> Given font name: DejaVu Sans
> Determined font file: /usr/share/fonts/TTF/mplus-1c-medium.ttf
> Actual font in that file: mplus-1c-medium
> Given font is present: #f/usr/share/fonts/TTF/mplus-1c-medium.ttf
> mplus-1c-medium

  Given font name: DejaVu Sans
  Determined font file: /usr/share/fonts/truetype/DejaVuSans.ttf
  Actual font in that file: DejaVuSans
  Given font is present: #f/usr/share/fonts/truetype/DejaVuSans.ttf
  DejaVuSans

Same as above: `DejaVuSans' != `DejaVu Sans'.

Since FontConfig version 2.11 (released October 2013), however, it is
possible to search for PostScript names also.  Example:

  $ fc-match "Alegreya"
  Alegreya-Regular.ttf: "Alegreya" "Regular"

  $ fc-match "AlegreyaRegular"
  arial.ttf: "Arial" "Normal"

  $ fc-match ":postscriptname=AlegreyaRegular"
  Alegreya-Regular.ttf: "Alegreya" "Regular"

Maybe lilypond's `display_fontset' function (in font-config-scheme.cc)
can be extended to display PS names also.  And perhaps it makes sense
to extend lilypond's font loading function to accept a font's PS name
– or to provide a Scheme function wrapper for FontConfig to access a
given font's PS name.


    Werner