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Re: [csswg-drafts] Proposal: cjk-dir: new property for RTL horizontal CJK, as well as for vertical CJK together with RTL(Arabic, Persian, etc.) text (#3608)

From: 張俊芝 via GitHub <sysbot+gh@w3.org>
Date: Mon, 04 Feb 2019 08:40:51 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-460168182-1549269650-sysbot+gh@w3.org>
> Unclear how this is a CJK-specific issue.
> 
> The figures in the original post seem to be about whether RTL scripts take a TTB inline progression in vertical lines. A rather typical use case is how RTL/TTB scripts (such as historical scripts Sogdian and Old Uyghur) can be rendered properly.
> 
> This is about how to override the default bidi behavior (as today’s common implementations of vertical writing simply rotate a whole horizontal line without changing the bidi behavior) with a unified direction for inline progression.

Thank you for the reply.

It's really about RTL/LTR, **in CSS**.

"writing-mode: vertical-*" combined with "direction: ltr" creates TTB inline progression,
while "writing-mode: vertical-*" combined with "direction: rtl" creates BTT inline progression.

It means in vertical mode in CSS, left is "mapped" to top, and right "mapped" to bottom.

"cjk-dir" changes the left to the right mapping in vertical mode.

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GitHub Notification of comment by Zhang-Junzhi
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Received on Monday, 4 February 2019 08:40:53 UTC

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