As discovered in #2067, matplotlib can not handle more modern TrueType fonts. An example of one such font is "Segoe UI" that ships with Windows 7 and 8. It has SFNT information in vendor tables other than "Macintosh" (in this case "Microsoft"), and it has post table of type 3 (we currently only support 1 through 2.5).

I think the iceberg here is really big, and rather than just trying to plug that hole, I think we should look long and hard at replacing our Freetype wrapper and font-subsetting code (ttconv) with something more modern. (ttconv dates from the early 1990's, for example).