--- a/ttml2/spec/ttml2-changes.html Wed Aug 28 13:21:48 2013 -0600
+++ b/ttml2/spec/ttml2-changes.html Wed Aug 28 13:38:55 2013 -0600
@@ -74,6 +74,9 @@
* In 8.3, add <border-color>, <border-style>, and <border-width>
value expressions.
+* In 8.3.12, add 'vw', 'vh', 'vmin', and 'vmax' units of measure in order to express
+ lengths as a percentage of the root container region (as viewport).
+
* In 8.4.4, add semantics for determining specified style set and computed style set
for 'set' element.
--- a/ttml2/spec/ttml2.xml Wed Aug 28 13:21:48 2013 -0600
+++ b/ttml2/spec/ttml2.xml Wed Aug 28 13:38:55 2013 -0600
@@ -6831,6 +6831,10 @@
: "px"
| "em"
| "c" // abbreviation of "cell"
+ | "vw"
+ | "vh"
+ | "vmin"
+ | "vmax"
</eg>
</td>
</tr>
@@ -6853,6 +6857,14 @@
<p>The semantics of the unit of measure <code>c</code> (cell) are
defined by the parameter <specref
ref="parameter-attribute-cellResolution"/>.</p>
+<p>The unit of measure <code>vw</code> and <code>vh</code> are defined as
+one percent (1%) of the width and height of the <emph>Root Container Region</emph>, respectively.
+For example, the length <code>25vw</code> is interpreted as 25% of the width of
+the <emph>Root Container Region</emph>.</p>
+<p>The units of measure <code>vmin</code> and <code>vmax</code> are defined as
+the minimum and maxium of <code>vw</code> and <code>vh</code>, respectively. For example,
+the length <code>25vmin</code> is interpreted as the minimum of 25% of the width and
+25% of the height of the <emph>Root Container Region</code></p>
</div3>
<div3 id="style-value-namedColor">
<head><namedColor></head>