Listing available sizes for a font

[Federico Mena Quintero <federico ximian com>]

Hi,

On a machine without XFT or with GDK_USE_XFT=0, GtkFontSelection shows
its normal set of sizes (8 to 72) for all faces, even though some of
them may not be available in some sizes --- bitmap fonts, of course.

Is there a way to get the list of available sizes for a face from
Pango?  I'd like to modify GtkFontSelection to display only the
available ones.

  Federico