Re: CJK variation modifier

From: John H. Jenkins (
Date: Sat May 19 2007 - 17:55:02 CDT

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    On May 19, 2007, at 5:54 AM, Gerrit Sangel wrote:

    > But using a separate font in case the character is now Chinese,
    > Japanese or
    > Korean is not always possible (think of file names, mp3 tags, plain
    > text
    > files and so on), so I wondered if there is something like a control
    > character in proposal?

    No. Glyphic variation controls of this type are inappropriate for
    plain text.

    Please remember, the unification work was done on the basis that the
    glyphs are perfectly legible, even when drawn with the standard shape
    used in a different locale.

    > It seems, there is also a Variation Database
    > accepted, but as far as I
    > understood it,
    > it is not really a clearly defined way, e.g. that variation 2 of
    > character x
    > has always the same specific appearance.

    TR37 is intended for different purposes.

    > There also seem to be some language tags in the SMP, but I don't
    > know if they
    > are used that way.

    They are not used that way. They are not intended to be used that
    way. They should never be used at all.

    > If there were a way to store the information about the variation of
    > the
    > character in the text itself, I think, it would be possible to
    > create a font
    > to include all CJK characters?

    The TrueType and derived font formats, which currently dominate the
    personal computer market, do not support fonts with more than 65,536
    glyphs, which is inadequate to cover all of the ideographic repertoire
    of Unicode even *without* locale-specific variants, so a TrueType/
    OpenType font covering all CJK characters is already impossible.

    A related question is to ask why one would want that? It is frankly
    much easier to have a Japanese-specific font and a traditional Chinese-
    specific font, and to let the user control how they want the
    characters to look by which font they use. Adding plain text tagging
    mechanisms to specify CJK glyph shape would simply involve
    considerable more work for text rendering engines.

    And, in any event, this is a non-problem. Typical users of Japanese
    do *not* want to see Japanese-specific shapes in Japanese text and
    traditional Chinese-specific shapes in Chinese text. They want to see
    Japanese-specific shapes all the time, regardless of the language
    being written. And they do this by specifying the locale on their
    computer to be Japan or by using a Japanese font.

    John H. Jenkins

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