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Re: [css3-writing-modes] A report from a meeting w/Japanese publishing group

From: koba <koba@antenna.co.jp>
Date: Sun, 15 Jan 2012 19:57:57 +0900
To: Brady Duga <duga@ljug.com>
Cc: MURATA Makoto <eb2m-mrt@asahi-net.or.jp>, "www-style@w3.org" <www-style@w3.org>
Message-Id: <20120115195756.24BE.A67A3BA5@antenna.co.jp>
> If I can just restate the issues in a very simplified manner to see if I am
> correct in my understanding of the problem:
> 1. In a vertical text flow, some glyphs may need to be rendered differently
> then in a horizontal flow (rotated or replaced)

Yes. Moreover, some characters may only be used for horizontal writing
mode, and some other characters may only be used for vertical writing

For example, please refer to:
3.1.1 Differences in Vertical and Horizontal Composition in Use of Punctuation Marks

> 2. This cannot always be determined algorithmically


Antenna House Formatter determines the direction of glyph by very 
heuristic method.

> 3. The writing modes module addresses this with styles to determine glyph
> orientation

This is difficult question. CSS writing mode can solve the issue only
partially.  For example, it can specify to rotate, but can not specify to 
change (replace)  the shape of glyph. 

The second problem is the behavior of graphics symbols (non-character)
are to be determined one by one.

I do not expect CSS writing mode module to solve everything.

> 4. Currently, glyph selection is a function of the underlying font engine
> (eg 'vert' gsub table in OpenType), not CSS (or Unicode)

Yes. The problem is some fonts do not supply such information as 'vert',
but in the future there will appear more intelligent/good fonts.

> Is item 4 the problem under discussion in the blog post? 

Partially, yes. 

But my overall intention is different.

Unicode TR#4 tries to classify every characters into U, S, SB, T.  
I supose it is impossible to classify some characters to one class. For
example, latin alphabet is U for 2.3.2.b.1-i fig. 24, but S for 2.3.2
b.1-ii fig.25.  

Please refer to 2.3.2 Major Differences between Vertical Writing Mode
and Horizontal Writing Mode.

As a result, the behavior of latin alpabet is U or S, it depends on
author's intent and writing style. It is not appropriate field for any
standard. Though, engineers may need default behavior for latin

My propose for Unicode TR#4 will be such that it determine minimum 
set of characters for which glyphs are to be rotated or for which the
chape of glyphs are to be replaced. 

> Is that the  original issue Koji raised? 

I do not understand which issue you refer.

> I apologize if these are obvious questions, I
> am having a little difficulty following the discussion - the Google
> Translate page of the blog post was surprisingly good, but I think some of
> the important details were lost.

No problem. I hope my explanation is good. 


Tokushige Kobayashi

koba <koba@antenna.co.jp>
twitter @TokKoba
Received on Sunday, 15 January 2012 10:58:44 UTC

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