Re: boustrophedon

From: Mark Leisher (
Date: Tue Nov 04 1997 - 15:49:33 EST

    Bernard> I've never dealt with any languages that use this. Let me
    Bernard> make sure I understand this, please.

    Bernard> 1. In Unicode, a particular codepoint has a default
    Bernard> directionality

    Bernard> 2. Using the special codes for Right-To-Left (RTL) and
    Bernard> Left-To-Right (LTR) we can override that default behavior.
    Bernard> These overrides are cleared by the codes paragraph
    Bernard> separator (2029) and line separator (2028).

Yes and yes.

    Bernard> 3. How do we designate "boustrophedon" as a directionality?
    Bernard> Is it implicit in the codepoint? Must we format each line
    Bernard> in advance with its directionality?

There is no existing boustrophedon directionality, so it can't be
explicitly designated. Thus the discussion. Should something be added
to Unicode or not?

Boustrophedon is not implicit in the codepoint. That would require the
addition of a new bidi property 'B'. Don't know if that is going to
happen. Formatting each line with directionality in advance is not
useful except for GUI activities.

    Bernard> 4. If the character layout must be flipped in some cases,
    Bernard> do we have two flavors of boustrophedon (flipped and
    Bernard> unflipped)? If so, is the flipping a function of the
    Bernard> codepoint, or the directionality?

From a character set standpoint, flipping is an application problem.
When your text changes direction, your rendering engine needs to either
flip glyph images or select alternate glyph sets (fonts) for display.
Mark Leisher "A designer knows he has achieved perfection
Computing Research Lab not when there is nothing left to add, but
New Mexico State University when there is nothing left to take away."
Box 30001, Dept. 3CRL -- Antoine de Saint-Exupéry
Las Cruces, NM 88003

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