Finding out what characters a given font supports

Question

How do I extract the list of supported Unicode characters from a TrueType or embedded OpenType font on Linux?

Is there a tool or a library I can use to process a .tt

Answer 1

The above Janus's answer (https://stackoverflow.com/a/19438403/431528) works. But python is too slow, especially for Asian fonts. It costs minutes for a 40MB file size font on my E5 computer.

So I write a little C++ program to do that. It is depends on FreeType2(https://www.freetype.org/). It is a vs2015 project, but it is easy to port to linux for it is a console application.

Code can be found here, https://github.com/zhk/AllCodePoints For the 40MB file size Asian font, it costs about 30 ms on my E5 computer.