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.
> 
> I guess Masamichi means that the mapping is not part of the font
> itself.

Yes. Thanks.

>>> 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.
> 
> Hopefully there is a solution that makes Cairo do the mapping work for
> us...

If I understand correctly, it is PDF readers that use Adobe-Japan1-UCS,
not PDF generators such as cairo.
If you use the PS backend and Ghostscript outputs the PDF,
it does not use Adobe-Japan1-UCS, but it works fine.