From: fantasai (fantasai.lists@inkedblade.net)
Date: Mon May 16 2011 - 20:34:11 CDT
On 05/16/2011 04:44 PM, Ken Whistler wrote:
> On 5/16/2011 3:33 PM, fantasai wrote:
>> I'd drop the "using digital layout" part but otherwise, yes, that's a
>> good definition. If we had such a property it would need to state for
>> each script:
>
> First of all, the Unicode Standard does not have any formal notion of
> properties for *scripts*. The properties in the Unicode Character Database
> are properties for *characters* (and/or code points).
Asmus suggested per script, so I wrote per script. If it's per character,
then you also need a concept of neutrality, as in the bidi algorithms.
> But the pushback you are encountering in this thread stems in part
> from the fact that the Unicode Standard is *not* a writing system
> or orthographical standard, and does not attempt to standardize issues
> of text layout, beyond the minimum required for plain text layout
> legibility. Hence the systematic lack of properties relating to
> any issues of vertical layout.
I would like to clarify that I am asking for an answer to the question
stated in the FAQ, and not for Unicode to address vertical layout. I
have no objection to Unicode providing additional data that would support
such layout, but that's out of scope for my particular request today. :)
>> - what vertical directionality it has (if any). Horizontal scripts
>> would be none. Most vertical scripts would be top-to-bottom. Going
>> by Michael Everson's answer, Ogham would be bottom-to-top.
>
> Ogham is not bottom-to-top. It is left-to-right in preferred directionality.
I will let you and Michael Everson argue over that then, because Ogham
is not my area of expertise. It seems to me that you, however, might want
to file an issue against Unicode 6 chapter 14.1, which states
"Ogham should therefore be rendered on computers from left to right
or from bottom to top (never starting from top to bottom)."
which implies a preferred bottom-to-top directionality.
>> - If it has vertical directionality, how the text is transformed from
>> horizontal to vertical, i.e. are grapheme clusters rotated (laid
>> sideways wrt horizontal) or translated (kept upright like CJK).
>
> I don't think that is sufficient. You also need to answer the question
> of how scripts which on their own are always laid out in horizontal
> lines behave when mixed laid out in vertical text as text inclusions.
That's a stylistic preference and should be controlled by the layout
system, since multiple answers are correct: how such text is laid out
is not inherent to the writing system. See UTN22 for more information
on this topic, and CSS3 Writing Modes for an example of how it can be
addressed.
UTN22 - http://unicode.org/notes/tn22/
CSS3 Writing Modes - http://www.w3.org/TR/css3-writing-modes/
~fantasai
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