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Re: WebVTT bidi: can we have ‎ and ‏ escapes?

From: Aharon (Vladimir) Lanin <aharon@google.com>
Date: Thu, 8 Dec 2011 21:05:03 +0200
Message-ID: <CA+FsOYaKGO0xJTzr4YrM7h443iiz3KG8sNmgUbzOezrHa7Z_DQ@mail.gmail.com>
To: "Phillips, Addison" <addison@lab126.com>
Cc: Kent Karlsson <kent.karlsson14@telia.com>, "public-texttracks@w3.org" <public-texttracks@w3.org>, "public-i18n-bidi@w3.org" <public-i18n-bidi@w3.org>
Yes. I was not suggesting LRE, RLE, and PDF because these are not really
human-usable. Even LRM and RLM push the envelope.

On Thu, Dec 8, 2011 at 7:21 PM, Phillips, Addison <addison@lab126.com>wrote:

> Blar! I read the characters incorrectly. The marks are not sequence
> forming, and Kent is correct.****
>
> ** **
>
> Addison****
>
> ** **
>
> Addison Phillips****
>
> Globalization Architect (Lab126)****
>
> Chair (W3C I18N WG)****
>
> ** **
>
> Internationalization is not a feature.****
>
> It is an architecture.****
>
> ** **
>
> ** **
>
> ** **
>
> *From:* Kent Karlsson [mailto:kent.karlsson14@telia.com]
> *Sent:* Thursday, December 08, 2011 8:58 AM
> *To:* Phillips, Addison; Aharon (Vladimir) Lanin; public-texttracks@w3.org;
> public-i18n-bidi@w3.org
> *Subject:* Re: WebVTT bidi: can we have &lrm; and &rlm; escapes?****
>
> ** **
>
> These marks, no, they are not terminated by anything. They are
> freestanding.
>
> LRE, LRO, RLE, and RLO are terminated (by PDF), since they do start a
> "span", but the marks don't.
>
>     /Kent K
>
>
> Den 2011-12-08 17:48, skrev "Phillips, Addison" <addison@lab126.com>:****
>
> You need a third character: U+202C (PDF). Sequences starting with RLM or
> LRM are terminated using this character. See:
> http://www.w3.org/International/questions/qa-bidi-controls.en.php
>
> Addison
>
> Addison Phillips
> Globalization Architect (Lab126)
> Chair (W3C I18N WG)
>
> Internationalization is not a feature.
> It is an architecture.
>
>
>
>
> *From:* Aharon (Vladimir) Lanin [mailto:aharon@google.com<aharon@google.com>]
>
> *Sent:* Thursday, December 08, 2011 12:43 AM
> *To:* public-texttracks@w3.org; public-i18n-bidi@w3.org
> *Subject:* WebVTT bidi: can we have &lrm; and &rlm; escapes?
>
>
> The WebVTT spec currently allows just three escapes: &lt;, &gt;, and
> &amp;. Authors are expected to enter any other characters directly by
> whatever other means they have at their disposal.
>
>
>
> I would like to suggest that an exception is needed for two more
> characters, LRM and RLM. These are invisible characters with strong
> directionality, LTR for one and RTL for the other. These are used in bidi
> text in two ways:
>
>
>
> - At the start of a paragrph, one of these can be used to indicate the
> paragraph's overall directionality in contexts where the directionality is
> determined by the paragraph's first character with strong direction. This
> is the default method of determining paragraph direction specified by the
> Unicode Bidirectional Algorithm - and the *only* method allowed by the
> current WebVTT spec. It is important to note that RTL languages fairly
> often use "words" spelled in LTR characters, e.g. acronyms like GPS and
> HTML (and WebVTT), as well as brand names. Occasionally, these occur as the
> first word in a sentence or even a paragraph, and when this is the case,
> the overall directionality of the paragraph is set incorrectly, unless one
> puts an RLM at the beginning of the paragraph.
>
>
>
> - In bidi text, these characters provide some means of control over the
> visual ordering of the characters. For example, to get "Mamma Mia!" to come
> out that way - and not as "!Mamma Mia" - in RTL text, one can put an LRM
> after the exclamation mark. In HTML, there are other means of such control,
> such as wrapping opposite-direction phrases in <span dir=...> or in a <bdi>
> element. But such means are absent in WebVTT.
>
>
>
> There are several reasons that I think an exception should be made for
> these characters and escapes provided for them in WebVTT:
>
>
>
> 1. As mentioned above, WebVTT does not provide any means for controlling
> paragraph directionality or inline directionality explicitly. Thus, the
> author has no means but LRM and RLM for such control in a WebVTT file.
>
>
>
> 2. LRM and RLM are invisible. Entering invisible characters and editing
> text that already contains them is confusing.
>
>
>
> 3. The existing standard Hebrew and Arabic keyboards do not provide a
> means of generating an actual LRM or RLM. Although the Windows native
> TextBox control provides a context menu that allows inserting various
> special characters including LRM and RLM, and Microsoft Notepad uses
> TextBox and thus provides the same context menu, most reasonable text
> editors available on Windows (e.g. Notepad++) are not based on TextBox and
> do not provide a means for generating LRM and RLM. The same, as far as I
> know, is true for Linux (e.g. gedit).
>
>
>
> Aharon****
>
Received on Thursday, 8 December 2011 19:06:03 UTC

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