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[Bug 28257] [webvtt] start/end linked to left/right [I18N-ISSUE-422]

From: <bugzilla@jessica.w3.org>
Date: Tue, 24 Nov 2015 11:46:49 +0000
To: www-international@w3.org
Message-ID: <bug-28257-4285-AtfER4AKRQ@http.www.w3.org/Bugs/Public/>
https://www.w3.org/Bugs/Public/show_bug.cgi?id=28257

--- Comment #10 from Silvia Pfeiffer <silviapfeiffer1@gmail.com> ---
(In reply to Addison Phillips from comment #9)
> I understand the problem of needing to position cues under a specific part
> of the screen (such as which side the speaking character appears on). In
> this case, you would want to use direction-specific keywords like 'left' and
> 'right' to ensure that the cue box doesn't "mirror" when the language is
> changed to Arabic and end up on the wrong side. But in other, more general,
> cases, you *do* want the mirroring to occur.


There is no use case in captioning where you want the mirroring of the cue box
to happen. The thing that should change direction is the text inside it, not
the box.


> In looking at the text this morning I see the formal description of these
> words in Section 3.1 under 'position' says:
> 
> ---
> If the cue text alignment is start or left, return 0 and abort these steps.
> 
> If the cue text alignment is end or right, return 100 and abort these steps.
> 
> If the cue text alignment is middle, return 50 and abort these steps.
> ---
> 
> This means that the direction neutral words are just synonyms for their
> direction specific brethren and we haven't solved the problem.


No it doesn't. You've skipped over the most important part of that section.
Here is the full quote:

--
A text track cue has a text track cue computed text position whose value is
that returned by the following algorithm, which is defined in terms of the
other aspects of the cue:

1. If the text track cue text position is numeric, then return the value of the
text track cue text position and abort these steps. (Otherwise, the text track
cue text position is the special value auto.)

2. If the text track cue text alignment is start or left, return 0 and abort
these steps.

3. If the text track cue text alignment is end or right, return 100 and abort
these steps.

4. If the text track cue text alignment is middle, return 50 and abort these
steps.
--


What it says is that: if the cue box position is not set explicitly (that's
1.), then the cue box's position depends on the alignment of the text inside
the box.

Further, the note below that text explains how this works for right-to-left
text:

--
Even for horizontal cues with right-to-left paragraph direction text, the cue
box is positioned from the left edge of the video frame. This allows defining a
rendering space template which can be filled with either left-to-right or
right-to-left paragraph direction text. If such a cue box template is created
with start or end aligned text, it is best to also specify a size since
otherwise the text may flip from one side of the video frame to the other.
--


It's a little tricky to follow, but it's correct.

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Received on Tuesday, 24 November 2015 11:46:52 UTC

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