[Fontconfig] Interaction of (web) document font families and fontconfig rules

[karlt+freedesktop at karlt.net]

On Fri, 21 Nov 2008 00:08:36 +0100, Juliusz Chroboczek wrote:

>> I'm looking for comments on how fontconfig users would prefer font
>> families defined in web documents through @font-face (or defined
>> by other means in other documents) to be presented in FcPattern *p
>> for FcConfigSubstitute(FcConfig*, p, FcMatchPattern).
>
> They should most certainly be treated specially.
>
> Consider the following.  There are googols of fonts called ``Garamond''.
> If two different web pages provide a font called Garamond, there's no
> reason to conclude that it's the same font; one could be an authentic
> French Renaissance font, while the other could be a stylistically very
> different 20th-century revival of the French Renaissance style.
>
> If both pages are viewed simultaneously in multiple browser windows, it
> should not possible for the two fonts to get mixed up -- each page should
> receive its own font --,

Yes, definitely.

> let alone for either to prevent me from using my locally
> installed font called Garamond (which happens to be a 20th
> century revival, but most probably one that is different from
> the second page's font).

There are a number of related scenarios here, and I'm not clear
exactly to which you are referring.

There is no way that a Garamond font provided by one web page
will affect which Garamond font you get on another web page or in
another app.

Normally your Garamond font will only be used for web content if
requested by the author, or if you have configured Garamond as a
default generic font and author-specified fonts are either
non-existing, disabled, or lacking support the character.  So there
is not really a use of the local Garamond to "prevent" here.