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Bug 14338 - <track> What does line position auto actually do?
Summary: <track> What does line position auto actually do?
Status: RESOLVED FIXED
Alias: None
Product: HTML WG
Classification: Unclassified
Component: HTML5 spec (show other bugs)
Version: unspecified
Hardware: Other other
: P3 blocker
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: HTML WG Bugzilla archive list
URL: http://www.whatwg.org/specs/web-apps/...
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-09-30 08:08 UTC by contributor
Modified: 2011-10-26 23:01 UTC (History)
8 users (show)

See Also:


Attachments

Description contributor 2011-09-30 08:08:28 UTC
Specification: http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html
Multipage: http://www.whatwg.org/C#text-track-cue-automatic-line-position
Complete: http://www.whatwg.org/c#text-track-cue-automatic-line-position

Comment:
<track> What does line position auto actually do?

Posted from: 83.218.67.122 by philipj@opera.com
User agent: Opera/9.80 (X11; Linux x86_64; U; Edition Next; en) Presto/2.9.205 Version/12.00
Comment 1 Philip Jägenstedt 2011-09-30 08:10:41 UTC
"A line position: Either a number giving the position of the lines of the cue, to be interpreted as defined by the writing direction and snap-to-lines flag of the cue, or the special value auto, which means the position is to depend on the other active tracks."

What should auto actually do here? Is it equivalent to -1, or is it completely UA-defined? If so, why?
Comment 2 Ian 'Hixie' Hickson 2011-10-02 16:37:58 UTC
It's all defined in the rendering section.
Comment 3 Philip Jägenstedt 2011-10-03 08:23:35 UTC
We can't find anything about "auto" and "line position" in http://www.whatwg.org/specs/web-apps/current-work/multipage/rendering.html#webvtt-cue-text-rendering-rules
Comment 4 Anne 2011-10-03 08:31:23 UTC
I can see line position referenced several times, but the algorithm does not seem to account for the "auto" value. E.g. it has let top be y-position followed by vw, which would not work for auto.
Comment 5 Ian 'Hixie' Hickson 2011-10-03 23:41:44 UTC
Yeah, wow. That's weird. I wonder how I missed that.

The DOM attribute for it also seems to be wrong (it gives a positive line number instead of a negative one).

I think I should fix this by introduce a new term "text track cue computed line position" which has the same value as the line position, unless it's auto, in which case it determines its value automatically, in the same way that the DOM attribute does now, except with a negated line number. Then, use that term in the rendering, and to define the DOM attribute.
Comment 6 Ian 'Hixie' Hickson 2011-10-26 23:00:29 UTC
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document:
   http://dev.w3.org/html5/decision-policy/decision-policy.html

Status: Accepted
Change Description: see diff given below
Rationale: see comment 5
Comment 7 contributor 2011-10-26 23:01:40 UTC
Checked in as WHATWG revision r6769.
Check-in comment: Somehow the automatic feature of cue line position was never properly specified.
http://html5.org/tools/web-apps-tracker?from=6768&to=6769