[Gs-devel] about OCF (Re: "rearranged font" CMap operators)

[mpsuzuki at hiroshima-u.ac.jp]

Dear Mr. Igor,

>I would very appreciate if you send changed files to me.
>My diff-merge tool appears some incompatible with format of your patch
>(I work on Windows).

Quite sorry, I will remake the patch as soon as possible.
The latest Cygwin is compatible with your environment?

>I learned about "rearranged font", and mostly know the subject.

Sorry, I was tedious. I wish if it could be some infomative
for the people unfamiliar with CMap/CID technology...

>Anyway thank you for explaining details - it looks that I missed 
>about ligatures...

Me too :-). Yamada-san found this feature from Unicode CMap,
and I understood what is "CODE_VALUE_CHARS" (in gxfont.h)
and why Peter stopped his implementation.

>By the way, some Adobe's implementations convert some
>CIDFont-CMap into OCF format while loading.
>Adobe calls this "OCF compatibility".
>Since you live in CJK world, maybe you can answer my old questions :
>
>- is OCF compatibility still actual ?

Hmm, although Adobe announces OCF will be disabled in future,
and most font vendors do not sell OCF anymore, still PS printers
/CPSI/DPS keep the functionalities to use OCF. We can use FMapType0-8.

# Why Adobe still supports OCF? It's not clear. But Japanese
# magazines for DTP are always talking about OCF compatibility.
# Morisawa: the most important Japanese font vender had ever sold
# the first Japanese PostScript font in OCF format (Ryumin-Light,
# and GothicBBB-Medium). It became de-facto standard of Japanese
# electro-publishing.
# When Morisawa sold CID version of these fonts, Morisawa replaced
# a few glyphs, and rewrote many BoundingBox infos. It introduced
# big troubles. So, the people who don't want to struggle with
# such incompatiblities are trying to use OCF forever.
# I suppose, this is Japanese special issue, and no such problem
# in China/Korea/Taiwan.
# 
# BTW: the fonts by Morisawa are beautiful but highly protected,
# too expensive, and un-embeddable. So, nobody checked them on GS,
# I suppose.

>- do any users need GS to support OCF compatibility ?

Possibly, nobody will make new OCF in future, but there are
a few free OCF in Japan. I suppose there are some users.
Although OCF is sensitive to wrong byte sequences, and
difficult to recover from decoding error, I want to keep
the back compatibilities as far as possible.

# For example, there are OCF Wadalab and CID-keyed Wadalab.
# CID-keyed Wadalab is processed by Adobe, but I found a glyph
# is corrupted. Incompatibility issue arises again... damn!

>No, we don't have such plans for nearest months.
>Your work on this would be very useful.

Thanks, I will continue.

>Perhaps I'll rewrite Type 1 hinter soon (I believe it is
>independent of decomposing text strings, which you only need
>to modify for "rearranged font").

Hmmm! Yes, no problem will be arise (rather, I should do so).
Rewriting of Type1 hinter sounds much interesting.
It makes me remember the gsft project by Mr. Zappa,
his work will be adopted?

Best Wishes,
mpsuzuki