Comment on PRI 98: IVD Adobe-Japan1 (pt.2)

Date: Tue Mar 13 2007 - 18:38:23 CST

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    Dear Sirs,

    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.

    CID+7641 U+28CDD
    CID+7655 U+3D4E
    CID+7670 U+25874
    CID+7672 U+8346
    CID+7673 U+28EF6
    CID+7687 U+6805
    CID+7825 U+21A1A
    CID+7834 U+67FA
    CID+7836 U+688E
    CID+7838 U+243D0

    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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