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RE: [css3-text] one dot leader (U+2024), vertical presentation form for vertical horizontal ellipsis (U+FE19)

From: Koji Ishii <kojiishi@gluesoft.co.jp>
Date: Thu, 30 Aug 2012 02:40:06 -0400
To: Glenn Adams <glenn@skynav.com>, W3C Style <www-style@w3.org>
Message-ID: <A592E245B36A8949BDB0A302B375FB4E0D5E63C4C8@MAILR001.mail.lan>
> So, what should the behavior be for U+2024 and U+FE19?
> My reading of the current text is that this behavior is unspecified,
> i.e., these may be considered as soft break opportunities,
> but this is left UA dependent. Is that the intended reading?

Yes. As discussed before, CSS Text Level 3 recommends differences between line-break values. We made this list by hearing typographic experts in CJK, and also by referring existing products. U+2025 and U+2026 were in the list to behave differently between normal/strict and loose, but U+2024 and U+FE19 were not.

So UA may change their behavior/class between normal/strict and loose, or keep consistent across values.


Regards,
Koji

-----Original Message-----
From: Glenn Adams [mailto:glenn@skynav.com] 
Sent: Thursday, August 30, 2012 11:53 AM
To: W3C Style
Subject: [css3-text] one dot leader (U+2024), vertical presentation form for vertical horizontal ellipsis (U+FE19)

UAX14 data [1] marks the following as belonging to the IN (inseparable) line breaking class:
• U+2024 (one dot leader)
• U+2025 (two dot leader)
• U+2026 (ellipsis)
• U+FE19 (presentation form for vertical horizontal ellipsis)
In contrast, CSS3 Text only specifies line break behavior for U+2025 and U+2026 [2].

Note that the UAX14 [3] behavior for all of these characters is to forbid breaking between any pair of these characters, i.e., they are considered as XP (exclude pair) characters. However, CSS3 Text does not specify that UAX14 semantics apply in any case with respect to the IN breaking class; i.e., the default line breaking rules in Section 5.1 [4].

So, what should the behavior be for U+2024 and U+FE19? My reading of the current text is that this behavior is unspecified, i.e., these may be considered as soft break opportunities, but this is left UA dependent. Is that the intended reading?

[1] http://www.unicode.org/Public/UNIDATA/LineBreak.txt

[2] http://dev.w3.org/csswg/css3-text/#line-break

[3] http://unicode.org/reports/tr14/#DescriptionOfProperties

[4] http://dev.w3.org/csswg/css3-text/#line-break-details


Received on Thursday, 30 August 2012 06:40:35 GMT

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