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<bugzilla version="5.0.4"
          urlbase="https://www.w3.org/Bugs/Public/"
          
          maintainer="sysbot+bugzilla@w3.org"
>

    <bug>
          <bug_id>22989</bug_id>
          
          <creation_ts>2013-08-17 00:04:21 +0000</creation_ts>
          <short_desc>[WebVTT] Clarify text position algo</short_desc>
          <delta_ts>2014-01-29 11:37:10 +0000</delta_ts>
          <reporter_accessible>1</reporter_accessible>
          <cclist_accessible>1</cclist_accessible>
          <classification_id>1</classification_id>
          <classification>Unclassified</classification>
          <product>TextTracks CG</product>
          <component>WebVTT</component>
          <version>unspecified</version>
          <rep_platform>PC</rep_platform>
          <op_sys>Linux</op_sys>
          <bug_status>RESOLVED</bug_status>
          <resolution>FIXED</resolution>
          
          
          <bug_file_loc></bug_file_loc>
          <status_whiteboard>v1</status_whiteboard>
          <keywords></keywords>
          <priority>P2</priority>
          <bug_severity>normal</bug_severity>
          <target_milestone>---</target_milestone>
          
          
          <everconfirmed>1</everconfirmed>
          <reporter>rpuri</reporter>
          <assigned_to name="Silvia Pfeiffer">silviapfeiffer1</assigned_to>
          <cc>mike</cc>
    
    <cc>philipj</cc>
    
    <cc>public-texttracks</cc>
    
    <cc>rpuri</cc>
          
          <qa_contact name="This bug has no owner yet - up for the taking">dave.null</qa_contact>

      

      

      

          <comment_sort_order>oldest_to_newest</comment_sort_order>  
          <long_desc isprivate="0" >
    <commentid>92210</commentid>
    <comment_count>0</comment_count>
    <who name="">rpuri</who>
    <bug_when>2013-08-17 00:04:21 +0000</bug_when>
    <thetext>I am having trouble following a portion of the spec outlined in the latest editor&apos;s draft obtainable from: https://dvcs.w3.org/hg/text-tracks/raw-file/default/webvtt/webvtt.html

Please note the following:

1. At one place in the document, a statement is made regarding the position of &apos;cue box&apos; within the video frame. Specifically, it is said that:

&quot;The position of the cue box within the video frame&apos;s dimensions depends on the value of the computed text position anchor point.&quot;

It appears that the above statement specifies the position of the &apos;cue box&apos; in relation to the &apos;value of the computed text position anchor point&apos;.

2. At another place in the document, the following statement is made:

&quot;The value of the computed text position anchor point is set as follows:&quot;
...
...
...
&quot;4. For left aligned cues with left-to-right paragraph direction [BIDI]: the first character of each line of text is positioned at the text track cue text position point within the video frame, otherwise the last character is positioned there.&quot;

It appears that the above statement specified the &apos;value of the computed text position anchor point&apos; in relation to &apos;text track cue text position&apos; point within the video frame.

3. At another place in the document, &apos;text track cue text position&apos; is defined as:

&quot;A number giving the position of the text within the cue box. If the cue is not within a region, the value is to be interpreted as a percentage of the box&apos;s size&quot;

From above, it appears that &apos;text track cue text position&apos; is defined in relation to the &apos;cue box&apos;.

This appears like an infnite loop to me. Am i reading this incorrectly or is there a bug here?</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>92221</commentid>
    <comment_count>1</comment_count>
    <who name="Silvia Pfeiffer">silviapfeiffer1</who>
    <bug_when>2013-08-17 12:09:46 +0000</bug_when>
    <thetext>Thanks for proof-reading the latest changes.

The first part that you reference is a note and not a normative statement. Therefore, there is no infinite loop.

That note summarizes what happens in the other statements. It should probably be extended to include the computed line position, too.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>92235</commentid>
    <comment_count>2</comment_count>
    <who name="">rpuri</who>
    <bug_when>2013-08-18 15:23:25 +0000</bug_when>
    <thetext>(In reply to comment #1)
&gt; Thanks for proof-reading the latest changes.
&gt; 
&gt; The first part that you reference is a note and not a normative statement.
&gt; Therefore, there is no infinite loop.
&gt; 
&gt; That note summarizes what happens in the other statements. It should
&gt; probably be extended to include the computed line position, too.

==========================================================
Thanks for the prompt clarification.

i still have a related concern and will attempt to capture that in the following: As an example, let us consider the case of a left aligned cue for a left-to-right paragraph direction text (as in the English language). In this case:

(1): the value of &apos;computed text position anchor point&apos; is &quot;first&quot;.

(2): it appears that in this case the value of the &apos;text position&apos; attribute manipulates the position of the first character of a line of text in the cue within the video frame. Informally speaking, say if &apos;text position&apos; had a value &apos;50%&apos;, then the first character would be positioned at the middle of the video frame.

(3) if above is true, why is text position defined to be as follows? &quot;A number giving the position of the text within the cue box. If the cue is not within a region, the value is to be interpreted as a percentage of the box&apos;s size, .....&quot;
 
(4) In other words, what would be incorrect about the following definition: &quot;A number giving the position of the anchor point of the text within the video frame&quot;

(5) I guess i am not able to follow how &apos;text position&apos; gives the position of text relative to the cue box.

Any example that clarifies what i might be overlooking would help.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>99410</commentid>
    <comment_count>3</comment_count>
    <who name="Philip Jägenstedt">philipj</who>
    <bug_when>2014-01-29 11:37:10 +0000</bug_when>
    <thetext>It seems to me that this issue has also been obsoleted by change Silvia made since the bug was filed. The &quot;computed text position anchor point&quot; concept is gone and so is the &quot;percentage of the box&apos;s size&quot; problem that https://www.w3.org/Bugs/Public/show_bug.cgi?id=23030 pointed out.

If there are still problems in this area, please file a new bug.</thetext>
  </long_desc>
      
      

    </bug>

</bugzilla>