Andrew C. West wrote:
Again, if you take the text out of the
presentational context you've warped it into, it doesn't make any sense.
To my way of thinking, if a text (such as an Ogham inscription) was originally
written vertically bottom to top, it makes just as much sense to render and read
it RTL as it does to render and read it LTR .
On paper, Ogham is traditionally written left to write. It /has/ a
horizontal directionality, so it doesn't make much sense to render
and read it the opposite way.
The text shouldn't depend on the font or text orientation switches being
exactly right.
And yet forced RTL Ogham text rendered horizontally with an ordinary Ogham font
would be no more illegible than plain Unicode Mongolian or Arabic displayed on a
system that only supports LTR with fonts that only display the fixed code chart
glyphs. Correct rendering of any complex script does depend on the correct
combination of fonts, rendering system and control codes; and you can't expect
all Unicode text to be displayed correctly irrespectiveof the sophistication of
your rendering system and fonts.
Yes, but rendering Mongolian and Arabic like that is due to a deficiency
in the system's Unicode support, not an ignored style rule.
Unicode directionality shouldn't be used as a presentational property;
that's the problem CSS3 Text has right now.
http://lists.w3.org/Archives/Public/www-style/2003Apr/0116.html
So, would your "solution" to embedding Ogham in vertical Mongolian be a
higher-level protocol, such as
<top-to-bottom>some Mongolian text <bottom-to-top>some Ogham
text</bottom-to-top> some more Mongolian text</top-to-bottom>
No. My solution would be to give Mongolian a top-to-bottom directionality
and Ogham a bottom-to-top directionality and let Unicode BIDI do a vertical
version of BIDI reordering. (Ideally, characters' vertical directionality would
be specified in Unicode. If they're not, then the rendering system itself would
have to assign BIDI properties based on characters' Unicode script values.)
Currently, 'direction' can be either 'ltr' or 'rtl'. My solution would give
it the following values:
ltr
Left-to-right directionality in horizontal text.
No inherent directionality in vertical text. (Effective direction
depends on style properties)
Examples: Latin, Tibetan scripts
rtl
Right-to-left directionality in horizontal text.
No inherent directionality in vertical text. (Effective direction
depends on style properties)
Examples: Arabic, Hebrew scripts
ttb
Top to bottom directionality in vertical text.
No inherent directionality in horizontal text. (Layout depends
on style properties)
Example: traditional Mongolian script
lr-tb
Left to right directionality in horizontal text.
Top to bottom directionality in vertical text.
Examples: Han, modern Yi scripts
lr-bt
Left to right directionality in horizontal text.
Bottom to top directionality in vertical text.
Example: Ogham?
Whether the text is laid out horizontally or verticaly would depend on
the style rules in effect. (In CSS3, the 'block-progression' values.)
~fantasai
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