[Fontconfig] Prgname and font-features?

[Behdad Esfahbod]

On 13-01-10 09:19 PM, Akira TAGOH wrote:

> On Fri, Jan 11, 2013 at 7:31 AM, Behdad Esfahbod <behdad at behdad.org
> <mailto:behdad at behdad.org>> wrote:
> 
>     Hi,
> 
>     I just pushed a change to Pango that allows one to enable OpenType font
>     features through fontconfig configs.  For example:
> 
>     <match target="font">
>       <edit name="pangofontfeatures" mode="append">
>         <string>smcp</string>
>         <string>ss20</string>
>       </edit>
>     </match>
> 
>     But I figured this is probably of interest to more than just Pango.  Shall we
>     upstream this?
> 
> 
> Thanks. yes. I was working on it and have a somewhat incomplete patch to Pango
> too, including pango markup support. it a bit got stuck because there are two
> issues I should address and didn't have a time to do:
> 
>  1) whether or not we should validate the given feature tag in config. it may
> be relevant to what you questioned at GNOME bug in other mail. on other hand,
> do we want to make another deps in fontconfig, i.e. harfbuzz for this purpose?
> otherwise what we can do for this is to add the object type for this and I've
> already done that in my repo: 
> http://cgit.freedesktop.org/~tagoh/fontconfig/commit/?h=bz50497

I don't think we should validate.  Just pass data around.  Should we call it
OT_FEATURES or more generically FONT_FEATURES?  If and when we add AAT support
(or the existing Graphite support), those backends will use these same tags as
far as HarfBuzz API is concerned.  CSS calls them font-features, that's why I
chose that.


>  2) This isn't really a fontconfig side but needed further work to allow to
> have multiple PangoAttribute at same time. if it's useful, I can send a patch
> to you. anyway, just to share my efforts,

Right.  That's why I've been putting this off.  I need to extend the
PangoAttribute framework to allow "reducing" a set of attributes to a single
value, in this case, add the lists of features together or something.


>     "pangoprgname", which pango sets to the output of g_get_prgname().  If you are
>     running gedit, it expands to gedit.  It's useful for doing per-app
>     configuration.  Any interest in upstreaming that?
> 
> Yeah, when that discussion was brought up here, I thought it would be useful
> if we can have similar thing in fontconfig. so users can manage the
> app-specific rules in config without modifying any code in apps.

Ok, I'll push it up.  Any name preference? FC_PRGNAME is fine?  Should
DefaultSubstitute try to populate that using system-specific heuristics?
(/proc/self/exe or something)


behdad