Re: Cairo plans

[Masamichi Hosoda]

>> Most PDF readers have a mapping
>> from Adobe-Japan1 CID to Unicode code points as follows.
>> https://github.com/adobe-type-tools/mapping-resources-pdf/blob/master/pdf2unicode/Adobe-Japan1-UCS2
> 
> Is it impossible to discover this mapping from the OTF file alone?

If I understand correctly, yes.

> Where does the OTF file say it is using encoding Adobe-Japan1-UCS

It is described in ROS in the CFF table.
https://docs.microsoft.com/en-us/typography/opentype/spec/cff
http://wwwimages.adobe.com/content/dam/Adobe/en/devnet/font/pdfs/5176.CFF.pdf

ROS means `Registry-Ordering-Supplement`.
For the current HaranoAjiMincho-Regular.otf,
Registry is `Adobe`, Ordering is `Japan1`, and Supplement is `7`.
So it is an `Adobe-Japan1-7` font.

PDF readers use Adobe-Japan1-UCS2 for `Adobe-Japan1-*` fonts.