[Fontconfig] Marking glyphs as deliberately blank, per font

[Nicolas Mailhot]

Le jeudi 26 novembre 2009 à 23:07 +0100, Nicolas Mailhot a écrit :
> Le jeudi 26 novembre 2009 à 22:06 +0100, Krzysztof Kotlenga a écrit
> :
> > Nicolas Mailhot wrote:

> > > And it would also be useful to define a <not/> operator, for
> example
> > > <not>
> > >  <lang>ja_Ja</lang>
> > > </not>
> > 
> > <test compare="not_eq">
> > ?
> 
> Another oververbose statement

Also one needs to distinguish between lang, as the lang resolution is
running for and lang, as the glyphs in a font file that correspond to a
particular .orth lang. Current fontconfig is geared for the first case.

But usually people who package fonts are interested by the second case
too (do something with Greek glyphs in font foo, not do something with
font foo when resolving for Greek). Of course both are often combined,
but just the first part is insufficient ("when resolving for Greek, use
Greek glyphs from font foo, then Greek Glyphs from font bar", is not the
same as "when resolving for Greek, use font foo, then font bar".

The second statement leads to Chinese users trying to override their own
overrides since a simple "when resolving for Chinese use font foo" has
the side effect of making base latin and common glyphs in font foo
override the default latin font if the lang is set to Chinese. So they
use weird constructs like "when the lang is Chinese, forget about
default font settings and put my chinese font first". Except oops, I've
just broken latin, so do also "when using my chinese font put this latin
font first". Therefore they need to know the right latin font fontconfig
would have chosen without their Chinese override (they do not)

-- 
Nicolas Mailhot