From: Kenneth Whistler (kenw@sybase.com)
Date: Thu May 13 2004 - 15:44:40 CDT
Elaine Keown continued:
> Kenneth Whistler wrote:
> > Yes.
> > The extent of directional layout required of a
> > *plain text* standard is the bidirectional
> > algorithm, which sorts out how a (horizontal) *line*
> > of text is laid out when text of opposite directions
>
>
> How did you decide that 'horizontal' is the default
> direction?
I guess you may not have parsed the parenthetical as I
intended. The bidirectional algorithm deals with layout
of a line of text in those conditions when left-to-right
characters and right-to-left characters are mixed in plain
text. It so happens that nearly all of the significant real contexts
where that happens (usually Arabic and/or Hebrew mixed with
Latin or a few other scripts) also involve *horizontal*
lines -- that clearly is the default layout convention
for Arabic, for Hebrew, for Latin, etc.
It doesn't *matter* however, for the purposes of the
bidirectional algorithm. If you rotate everything 90 degrees
and lay out the text vertically, the bidirectional algorithm
would still need to be applied to resolve the two mixed
directions in that (vertical) line of text.
> My impression is that 85 - 95% of *all*
> elements of writing ever invented by humans are
> Chinese (or other ..JKV...).
So? Japanese and Chinese are both written vertically *or*
horizontally. And that doesn't have anything to do with
the definition of the bidirectional algorithm, anyway.
> Does 'horizontal' actually come from hardware, not
> software? Is it built into the computer screen?
No and no. Hardware considerations for text layout became
obsolete with the appearance of the bit-mapped graphic screen
display for the Macintosh in 1984.
--Ken
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