- From: Ian Hickson via cvs-syncmail <cvsmail@w3.org>
- Date: Tue, 24 Apr 2012 21:14:44 +0000
- To: public-html-commits@w3.org
Update of /sources/public/html5/webvtt
In directory hutz:/tmp/cvs-serv4509
Modified Files:
Overview.html
Log Message:
Try to clarify line breaking, balancing, and bidi handling in WebVTT. (whatwg r7062)
Index: Overview.html
===================================================================
RCS file: /sources/public/html5/webvtt/Overview.html,v
retrieving revision 1.13
retrieving revision 1.14
diff -u -d -r1.13 -r1.14
--- Overview.html 19 Apr 2012 22:54:21 -0000 1.13
+++ Overview.html 24 Apr 2012 21:14:41 -0000 1.14
@@ -122,7 +122,7 @@
<header class=head id=head><!-- the following line added by request of Ian Jacobs --><p class=logo><a href=http://www.w3.org/><img alt=W3C height=48 src=http://www.w3.org/Icons/w3c_home width=72></a></p>
<hgroup><h1 class="no-num no-toc">WebVTT</h1>
- <h2 class="no-num no-toc">Living Standard — Last Updated 19 April 2012</h2>
+ <h2 class="no-num no-toc">Living Standard — Last Updated 24 April 2012</h2>
</hgroup><dl><dt>Latest version:</dt>
<dd><a href=http://http://dev.w3.org/html5/webvtt/>http://dev.w3.org/html5/webvtt/</a></dd>
<dt>Participate:</dt>
@@ -2125,18 +2125,14 @@
<li>
<p>Apply the Unicode Bidirectional Algorithm's Paragraph Level
- steps to <var title="">nodes</var> using the following
- constraints, to determine the <i>paragraph embedding level</i>
- of the cue: <a href=#refsBIDI>[BIDI]</a></p>
-
- <ul><li><var title="">nodes</var> represents a single paragraph.</li>
-
- <li>The paragraph's text consists of the concatenation of the
- values of each <a href=#webvtt-text-object>WebVTT Text Object</a> in <var title="">nodes</var>, in a pre-order, depth-first traversal,
- excluding <a href=#webvtt-ruby-text-object title="WebVTT Ruby Text Object">WebVTT Ruby
- Text Objects</a> and their descendants.</li>
+ steps to the concatenation of the values of each <a href=#webvtt-text-object>WebVTT
+ Text Object</a> in <var title="">nodes</var>, in a pre-order,
+ depth-first traversal, excluding <a href=#webvtt-ruby-text-object title="WebVTT Ruby Text
+ Object">WebVTT Ruby Text Objects</a> and their descendants,
+ to determine the <i>paragraph embedding level</i> of the first
+ Unicode paragraph of the cue. <a href=#refsBIDI>[BIDI]</a></p>
- </ul></li>
+ </li>
<li>
@@ -2372,14 +2368,26 @@
were calculated earlier in this algorithm.)</li>
<li>Text runs must be wrapped according to the CSS
- line-wrapping rules, except that additionally, regardless of
- the value of the 'white-space' property, lines must be wrapped
- at the edge of their containing blocks, even if doing so
- requires splitting a word where there is no line breaking
- opportunity. (Thus, normally text wraps as needed, but if there
- is a particularly long word, it does not overflow as it
- normally would in CSS, it is instead forcibly wrapped at the
- box's edge.)</li>
+ line-wrapping rules, with the following additional constraints:
+
+ <ul><li>Regardless of the value of the 'white-space' property,
+ lines must be wrapped at the edge of their containing blocks,
+ even if doing so requires splitting a word where there is no
+ line breaking opportunity. (Thus, normally text wraps as
+ needed, but if there is a particularly long word, it does not
+ overflow as it normally would in CSS, it is instead forcibly
+ wrapped at the box's edge.)</li>
+
+ <li>Regardless of the value of the 'white-space' property,
+ any line breaks inserted by the user agent for the purposes
+ of line wrapping must be placed so as to minimise Δ
+ across each run of consecutive lines between preserved
+ newlines in the source. Δ for a set of lines is defined
+ as the sum over each line of the absolute of the difference
+ between the line's length and the mean line length of the
+ set.</li>
+
+ </ul></li>
<li>The viewport (and initial containing block) is
<var title="">video</var>'s rendering area.</li>
@@ -2623,8 +2631,8 @@
<h4 id=applying-css-properties-to-webvtt-node-objects><span class=secno>3.5.1 </span>Applying CSS properties to <a href=#webvtt-node-object title="WebVTT Node Object">WebVTT Node Objects</a></h4>
<p>When following the <a href=#rules-for-updating-the-display-of-webvtt-text-tracks>rules for updating the display of WebVTT
- text tracks</a>, user agents must set properties of <a href=#webvtt-node-object title="WebVTT Node Object">WebVTT Node Objects</a> as defined in
- this section. <a href=#refsCSS>[CSS]</a></p>
+ text tracks</a>, user agents must set properties of <a href=#webvtt-node-object title="WebVTT Node Object">WebVTT Node Objects</a> at the CSS
+ user agent cascade layer as defined in this section. <a href=#refsCSS>[CSS]</a></p>
<p>On the (root) <a href=#list-of-webvtt-node-objects>List of WebVTT Node Objects</a>, the
'position' property must be set to 'absolute', the 'direction'
@@ -2662,6 +2670,9 @@
of WebVTT Node Objects</a>, if supported.</p> <!-- 'text-outline'
is in CSS3 Text, but Tab says that's awaiting medical attention. -->
+ <p>The 'white-space' property on the (root) <a href=#list-of-webvtt-node-objects>List of WebVTT
+ Node Objects</a> must be set to 'pre-wrap'. <a href=#refsCSS>[CSS]</a></p>
+
<p>The 'font-style' property on <a href=#webvtt-italic-object title="WebVTT Italic
Object">WebVTT Italic Objects</a> must be set to 'italic'.</p>
@@ -2678,10 +2689,6 @@
Object">WebVTT Ruby Text Objects</a> must be set to
'ruby-text'. <a href=#refsCSSRUBY>[CSSRUBY]</a></p>
- <p>If there are style sheets that apply to the <a href=#media-element>media
- element</a> or other playback mechanism, then they must be
- interpreted as defined in the next section.</p>
-
<p>All other non-inherited properties must be set to their initial
values; inherited properties on the root <a href=#list-of-webvtt-node-objects>List of WebVTT Node
Objects</a> must inherit their values from the <a href=#media-element>media
@@ -2692,6 +2699,10 @@
<a href=#list-of-webvtt-node-objects>List of WebVTT Node Objects</a> must take their initial
values.</p>
+ <p>If there are style sheets that apply to the <a href=#media-element>media
+ element</a> or other playback mechanism, then they must be
+ interpreted as defined in the next section.</p>
+
<h4 id=css-extensions><span class=secno>3.5.2 </span>CSS extensions</h4>
@@ -2744,6 +2755,7 @@
<li>the properties corresponding to the 'background' shorthand</li>
<li>the properties corresponding to the 'outline' shorthand</li>
<li>the properties corresponding to the 'font' shorthand, including 'line-height'</li>
+ <li>'white-space'</li>
<!-- add more... -->
<!-- definitely not:
display, float, position, top, left, right, bottom, width,
@@ -2838,7 +2850,7 @@
<li>the properties corresponding to the 'outline' shorthand</li>
<li>properties relating to the transition and animation features</li>
<!-- add more... -->
- <!-- but definitely not anything that affects dimensions of boxes, e.g. the 'font' shorthand's properties -->
+ <!-- but definitely not anything that affects dimensions of boxes, e.g. the 'font' shorthand's properties or 'white-space'; those are listed below instead -->
</ul><!--v2
Would be nice to support transitions that are directional,
e.g. changing text fill colour or shadow size of the start of a
@@ -2850,6 +2862,7 @@
the <a href=#past-pseudo-class title=past-pseudo-class>':past'</a> and <a href=#future-pseudo-class title=future-pseudo-class>':future'</a> pseudo-classes:</p>
<ul class=brief><li>the properties corresponding to the 'font' shorthand, including 'line-height'</li>
+ <li>'white-space'</li>
<!-- add more... -->
<!-- definitely not:
display, float, position, top, left, right, bottom, width,
Received on Tuesday, 24 April 2012 21:14:48 UTC