Re: Multiple Directions (was: Re: Coptic/Greek (Re: Phoenician))

From: Andrew C. West (
Date: Fri May 14 2004 - 12:07:06 CDT

  • Next message: Michael Everson: "RE: interleaved ordering (was RE: Phoenician)"
    ('binary' encoding is not supported, stored as-is) ('binary' encoding is not supported, stored as-is) On Fri, 14 May 2004 11:43:53 -0400, wrote:
    > Andrew C. West scripsit:
    > > In bilingual Manchu-Chinese texts, which were common during
    > > the Manchu Qing dynasty [1644-1911], the text normally follows the Manchu
    > > layout, with vertical lines of Manchu and Chinese interleaved from left to
    > right
    > > across the page, so that from a Chinese perspective the book reads backwards.
    > Most interesting. What about codex binding? When I see people reading
    > Chinese newspapers on the subway, the binding appears to be on the left
    > even though the columns of the text are RTL; at least, judging by what
    > appears to be the front page.

    For vertically laid out Chinese books, the front cover corresponds to the back
    cover of an English book, and the back cover corresponds to the front cover of
    an English book, so from a Western perspective such books appear to be read
    backwards. Traditionally-bound bilingual Manchu-Chinese books are read the same
    way as Western books ... which is backwards from a Chinese perspective.

    As to newspapers, these normally follow Western newspaper page order, regardless
    of whether the content is laid out horizontally, vertically or mixed horizontal
    and vertical.

    > > As I suggested in a recent thread on mixed horizontal/vertical layout, if you
    > > did have mixed Top-To-Bottom (TTB) and Bottom-To-Top (BTT) scripts such as
    > > Mongolian and Ogham [...] then you
    > > could deal with their conflicting directionality as if they were rotated LTR
    > and
    > > RTL scripts by means of LRO, RLO and PDF control codes [202C..202D].
    > Surely that's not enough: you'd need to implement the full implicit bidi
    > algorithm, giving Ogham a nonce bidi type of R. Either that, or run the
    > Ogham T2B instead of the normal direction.

    Have a look at the attached images which show Mongolian text with embedded Ogham
    (laid out horizontally).

    In "Mongolian with embedded LTR Ogham" both Mongolian and Ogham are LTR by

    In "Mongolian with embedded RTL Ogham" Mongolian is LTR by default, but the
    Ogham has been made RTL by sandwiching it between an RLO control code and a PDF
    control code (i.e. <202E, 1680, 1692, 1682, 1689, 1690, 168C, 1685, 1694, 1680,
    202C>). Thanks to Uniscribe this magically has the effect of reversing the flow
    of the embedded Ogham text. This does not quite work, however, as although the
    glyph order has been reversed the glyphs have not been rotated 180 degrees, with
    the result that they are the wrong way round. But an Ogham font that was
    specifically designed for RTL/BTT usage would have glyphs that are rotated 180
    degrees compared with those in the Unicode code chart, and with such a font this
    embedded RTL Ogham test text would be rendered correctly. Now all you would need
    is a text editor that rotated the whole thing 90 degrees, and you would have BTT
    Ogham embedded in TTB Mongolian ... with no messy fiddling with the bidi

    And if you really wanted to be clever, you could perform the same trick by
    embedding LTR Ogham in RTL Mongolian (using an RTL Mongolian font ... which do
    exist, although I don't know of any Unicode RTL Mongolian fonts yet), and
    rotating the whole thing 270 degrees ... I think ... my head's started to spin
    at this point ...


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