Re: Vertical BIDI

From: Timothy Partridge (
Date: Wed May 19 2004 - 14:14:50 CDT

  • Next message: Michael Everson: "ISO 15924 draft fixes"

    Philippe Verdy recently said:

    > From: <>

    > > What's uncertain is whether a lr or a rl progression is favored, given the
    > > paucity of evidence. Michael favors lr progression. There is no question
    > > that the text is read BTT.

    > This creates an interesting problem: Put in the same sentence Han (Chinese) and
    > Mongolian words in a vertical layout (I don't think this is unlikely, as
    > Mongolian is also spoken in China, and there's also a Chinese community in
    > Mongolia). So Chinese ideographs will be laid out vertically from top to bottom
    > (but not rotated, except for a few characters like ideographic punctuation marks
    > or symbols), and Mongolian will be laid out from bottom to top in their normal
    > stack orientation. Such a text is clearly bidirectional, so we would need BiDi
    > processing to order glyphs correctly.

    John's comment refers to Ogham. Mongolian goes top to bottom.

    > Now try including some Latin words in this text (also not unlikely: there are
    > lots of trademarks and people names that will need to be written with their
    > normal Latin characters). If the text is presented vertically, there's a
    > legitimate question of whever Latin should be rotated (but it will keep the Han
    > flow direction.)

    Latin and Cyrillic are rotated 90 degrees clockwise when mixed with
    Mongolian in vertical lines. Presumably Arabic would be rotated 90 degrees
    anti-clockwise. (The ancestor of Mongolian was which is why the vertical
    lines go left to right.) One amusing aspect is that punctuation like ? and !
    stay vertical at the end of Mongolian sentances, but are rotated at the end
    of Latin and Cyrillic ones.

    Mongolian is somewhat unusual in that nowadays when it is written in
    horizontal lines, it is rotated a further 90 degrees so it goes left to
    right and is upside down compared to the ancestral script.


    Tim Partridge. Any opinions expressed are mine only and not those of my employer

    This archive was generated by hypermail 2.1.5 : Wed May 19 2004 - 22:06:41 CDT