Font support in circled-decimal and parenthesized-decimal #68

Adobe-Japan1 is a character collection defined by Adobe and is the standard for all Japanese font production. The glyphs are shown in https://github.com/adobe-type-tools/Adobe-Japan1/raw/master/Adobe-Japan1-7.pdf

There are many levels, the most commonly used is Adobe-Japan1-3, which contains a total of 9354 characters, of which 7014 are Kanji characters. Japanese font companies usually use Adobe-Japan1 instead of Unicode as the character set standard, just like Chinese font companies (in Mainland China) use Guobiao as the standard.

From Eric Liu:

For Japanese fonts, if it is the so-called Std font and supports Adobe-Japan1-3, the circled decimals are supported up to 31, and the bracketed digits are supported up to (20); if it is Pro font and supports Adobe-Japan1-4, the digits are supported up to 100. Unicode only encodes up to 50, so for glyphs above 50, there is no Unicode mapping for the time being.

Example Adob​​e-Japan1-4 fonts:

• A-OTF Jun Pro
• UDDigiKyokasho Pro