保存
https://docs.microsoft.com/en-us/typography/opentype/spec/index
glyf：
https://docs.microsoft.com/zh-cn/typography/opentype/spec/glyf
https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6glyf.html
fonttools：
http://pyopengl.sourceforge.net/pydoc/fontTools.html
fontcreator：
https://pan.baidu.com/s/1IswcShG3q4lCo4BomxmAJw
