Re: GB 18030 Certification

From: Christopher Fynn (
Date: Fri Aug 19 2005 - 01:25:14 CDT

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    Patrick Andries wrote:

    > Does the GB 10840 Certfication require that Chinese Minority scripts be
    > displayed properly (i.e Mongolian or Tibetan) ?
    > Would greatly appreciate any details,
    > P. A.

    There are different levels of compliance ...

    e.g. for displaying Tibetan at the lowest level of compliance you just
    have to be able to display a defalt glyph for each character (e.g. a
    glyph like those in
    the io10646 / Unicode code charts) - without necessarily forming proper
    ligatures (shaping). Of course this is pretty well useless for normal
    users since, unless you display proper "stack" ligatures for conjuncts,
    Tibetan text is pretty well unreadable.

    For a higher level of compliance you will now have to be able to
    properly display ligatures for a sub-set of about 1500 Tibetan
    combinations ("Set A" used in modern publications)

    For the highest (A+) level of compliance you will have to be able to
    properly display proper ligatures for an additional set of over 5,500
    Tibetan combinations ( ("Tibetan Set B" additional combinations found in
    tradtional Tibetan texts).

    This is further complicated since in some Chinese encodings and systems
    they seem to use the combintatons (ligature gyphs) in their Tibetan sets
    A and B as (pre-composed composite) *characters* mapped to fixed
    Unicode PUA and supplementary PUA code points. While this avoids the
    need for OpenType or similar shaping to properly dsplay Tibetan text it
    means that text needs to be converted to (de-composed) Unicode for other

    - Chris

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