Re: GTK+3 fonts

[Michael Torrie <torriem gmail com>]

On 10/21/2012 01:58 PM, Roger Davis wrote:
> % fc-match Sans
> DejaVuSans.ttf: "DejaVu Sans" "Book"
>
> And if I put them back, things are restored as before:
>
> % fc-match Sans
> Vera.ttf: "Bitstream Vera Sans" "Roman"
>
> Can anyone explain how this works? Is there some complicated font 
> parameter examination taking place here, or is it as simple, at least in 
> some cases, as a single defined fallback font for everything when a 
> specified font cannot be located? Curiously, this test returns the same 
> fallback font:
>
> % fc-match yuk-yuk
> Vera.ttf: "Bitstream Vera Sans" "Roman"
>
> I suppose what I would like to do on my Mac is have it use DejaVu Sans to 
> satisfy a Sans request (because DejaVu has the UTF-8 characters I need and 
> Vera does not), but without having to delete the Vera fonts from my 
> system, which might break God-knows-what-all. Is there a way to do this?

All of this is specified in the fontconfig configs.  On linux, this is
normally in /etc/fonts/conf*.  I don't know where they are on macports,
but probably in a similar path, maybe /opt/etc/fonts.  These config
files specify the logic fontconfig should use in searching for a font
which is rendered via freetype.  Substitutions and fallback fonts are
all specified here.  This way if someone just requests "sans" or
"roman," they get a suitable font, if installed, or the fallback font.
Also fontconfig specifies what to do at smaller font sizes, how to do
hinting, etc.  It's possible that the hinting is changing as the font
get smaller.  Maybe on macports they default to having more and more
hinting at smaller sizes for legibility, whereas on CentOS they don't
turn on as much hinting (I turn it off completely on my Fedora machines).