Comment Re:Fonts missing in action (Score 1) 165
I'm pretty sure most font systems already DO do this.
Usually not the font systems themselves, as the font system API needs to be designed to let you use fonts in the way that suits your application, and not have random substitutions happen behind your back (though the font system provides the API functions to figure out what a good substitution font will be). But higher level UI libraries, like GTK, Qt, MFC, Windows Forms,Core Text, Skia etc will do it.