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

[Urs Liska]

Am 28.04.2015 um 20:16 schrieb David Nalesnik:

Hi Urs,

On Tue, Apr 28, 2015 at 11:38 AM, Urs Liska <address@hidden> wrote:

Am 28.04.2015 um 18:14 schrieb Urs Liska:

Am 28.04.2015 um 17:53 schrieb Urs Liska:

I think I have found something.

After some experimenting with a copy of font-config-get-font-file and trying different approaches I could guess from the documentations available I found that replacing an item in the FcPatternGetString call this function returns the font name and not the Postscript name or the font file.

The following preliminary function (if added to font-config-scheme.cc) returns either the Font Name (if the font exists) or "Emmentaler-11" (on my system) if it doesn't exist. I assume it would return other names on other systems:

LY_DEFINE (ly_font_config_font_exists, "ly:font-config-font-exists", 1, 0, 0,

...

Best
Urs

Wrapping this Scheme function around that:

fontExists =
#(define-scheme-function (parser location font-name)(string?)
   (string=? font-name (ly:font-config-font-exists font-name)))

shows that my idea is right: The C++ function returns the family name of either the given font or the (system-dependent) fallback font. Now all there would be to it is moving the comparison of the latter Scheme function to the C++ function .

Urs

Last one for this working session: The following function ly:font-config-font-exists will return true or false depending on whether the given font is available.

I tried this out on my VM (Ubuntu 10.04.4 -- yes, I need to update to the most recent LilyDev...)

Should it work for any font that's listed by ly:font-config-display-fonts?  It works for most of the names I've tried, though not all.  For example. "Kedage" returns #f.

AFAICS it should, What is the "font name" of Kedage?
You could try out with my version from the second-to-last post, which returns the "plain" result of the fontconfig lookup.

 

The only drawback (yet) is that now the comparison is case sensitive. But *that* should be easy now?

I don't find anything convenient.  I suppose you could just convert both strings to lower- or uppercase and then compare.

An Unicode/utf8 things to consider here?

But is this desirable?  I mean, is LilyPond ever case-insensitive?

Well, when calling *text* fonts it has always been case insensitive. And I would like to keep that because you can't really look into the fonts to know how they are capitalized. So I'd be happy if we can make music fonts case insensitive too instead of the other way round.

Urs

Thanks for working on this!

David