character-map

A simple command line tool for dumping a UTF-8 string of characters supported by a font file.

Motivation

Unicode fonts are usually too large to be embedded as webfont: subsetting is necessary to get them into a reasonable size, especially for CJK fonts.

But which ones do you subset to ensure your design look consistent? There are 2 major approaches:

• Dynamic subsetting: using javascript and server-side api to generate a dynamic subset of your font, covering all characters on your webpage.
• Static subsetting: prepare a list common characters, subset them manually, and use such font only for certain elements on webpage.

I prefer the latter approach, because it's a lot easier to optimize and has less of an impact to performance.

And Apple agrees, their sites for China Mainland, Hong Kong and Japan all use this approach.

But I wonder what characters they pick for their CJK subsets?

character-map to the rescue!

Install

npm install character-map -g

Usage

TrueType, OpenType, WOFF v1 files are supported at the moment.

$ character-map -f my.ttf > map.txt

map.txt will contain a list of characters found in the font. Now you can use this result with a subsetting tool like fontmin.

$ fontmin -t `cat map.txt` other.ttf > subset.ttf

Of course you can verify the result with character-map again.

License

MIT

Acknowledgement

Inspired by CharacterMap and uses opentype.js.