Date: Tue Mar 13 2007 - 18:38:23 CST
Next, my comment 1 & 2.
Comment 1: codepoint coverage of Adobe-Japan1
I think, if the codepoints in IVD Adobe-Japan1 fit into
the coverage defined by ISO/IEC 10646 JTC1/SC2/WG2
N3091 "Request For Collection Identifiers For Japanese
Subsets of ISO/IEC 10646" (proposed by Japan National
Body, it was accepted and will be included in future
ISO 10646 ammendment). In it, 5 subsets are defined
based on JIS and vendor character set.
If the coverage of Adobe-Japan1 can be expressed by
the simple combination of the subsets, it will be very
helpful for information interchange in Japan.
Adobe-Japan1 IVS includes following 10 characters whose
codepoint is not included in N3091 subsets.
I wish if these CIDs are reconsidered to fit N3091 subsets,
for easier information interchange in Japanese markets.
Detailed analysis will be discussed in Comment 7.
Comment 2: codepoints in CJK Compatibility Ideographs
The codepoints of current IVD Adobe-Japan1 covers whole of
JIS X 0208 ("Basic Japanese" of N3091) and whole of JIS X 0212
("Japanese Ideographics Supplement" of N3091). But JIS X 0213
("JIS2004 Ideographics Extension" of N3091) and common Japanese
vendor extensions ("Common Japanese" of N3091) are covered
partially. I think, partial coverage is slightly confusing.
Being covered completely or not covered at all is clearer and
might be easier to understand. It seems that the uncovered
codepoints are of CJK Compatibility Ideographs.
According to TechNote #5078, Adobe CMaps and cid2code.txt,
Adobe-Japan1-6 is designed to cover JIS X 0213 and
most vendor extended Shift-JIS variants (e.g. Microsoft
codepage 932), but the most codepoints of CJK Compatibility
Ideographs for JIS X 0213 compatibility and common Japanese
vendor extension are not used in the proposal (in following,
I call them "avoided codepoints"). I guess, the avoided
codepoints are just "the out of scope" of IVD Adobe-Japan1
(in fact, Unicode Technical Report #37 is written for CJK
Unified Ideographs, no mention about CJK Compatibility
Ideographs), and IVD Adobe-Japan1 does not concern the
availability of ideographs at the avoided codepoints.
However, if we use IVD Adobe-Japan1 in ToUnicode mapping
tables in PDF using Adobe-Japan1 CID font, it can cause
a round-trip issue. For example, if I make a PDF from
JIS X 0213 text, with Adobe CID font, and insert ToUnicode
mapping tables including IVS of IVD Adobe-Japan1,
the receiver of PDF file can retrieve JIS X 0208 (and/or
0212) text from the PDF, but cannot retrieve original JIS
X 0213 text.
If IVD for CJK Compatibility Ideographs should NOT be defined,
I wish if IVD Adobe-Japan1 proposal includes NFD from JIS X
0213 to JIS X 0208 + 0212, to prevent the round-trip issue by
wrong utilization of IVD Adobe-Japan1.
I want JIS and IRG experts to give comments about the IVD for
CJK Compatibility Ideographs.
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