[ttml1,ttml2] add notes elaborating meaning of "closest supported value"
authorGlenn Adams <glenn@skynav.com>
Tue, 27 Aug 2013 12:30:56 -0600
changeset 512 24ed1e6adcdd
parent 511 83a53e788366
child 513 2b7e64ab0f59
[ttml1,ttml2] add notes elaborating meaning of "closest supported value"
ttml1/spec/ttml1-changes.html
ttml1/spec/ttml1.xml
ttml2/spec/ttml2.xml
--- a/ttml1/spec/ttml1-changes.html	Tue Aug 27 12:14:15 2013 -0600
+++ b/ttml1/spec/ttml1-changes.html	Tue Aug 27 12:30:56 2013 -0600
@@ -74,25 +74,31 @@
   tt element, since it doesn't support TTS style properties, and since style content
   style inheritance stops at body and region style inheritance stops at region.
 
-* In 8.2.9, improve compatibility with CSS and XSL-FO implementations by interpreting
-  'normal' line height as 120% (1.2 multiplier) of relevant font size instead of 100%
-  (1.0 multiplier).
-
 * In 8.2.9, elaborate semantics for resolving percentage font size on region element,
   in which case computed cell size is used as a reference.
 
 * In 8.2.9, elaborate note that explains use of single cell-based length to also include
   case of two cell-based lengths.
 
+* In 8.2.9, add note clarifying the meaning of closest supported value.
+
 * In 8.2.12, correct typo where "initial" value was written, but "computed" value
   intended.
 
 * In 8.2.12, clarify that the interpretation of "normal" is scoped by descendants in a
   intermediate synchronic document.
 
+* In 8.2.12, improve compatibility with CSS and XSL-FO implementations by interpreting
+  'normal' line height as 120% (1.2 multiplier) of relevant font size instead of 100%
+  (1.0 multiplier).
+
 * In 8.2.13, correct typo where "initial" value was written, but "computed" value
   intended.
 
+* In 8.3.1, add note clarifying the meaning of closest supported value.
+
+* In 8.3.2, add note clarifying the meaning of closest supported value.
+
 * In 8.4.2.1, add note clarifying that the body element, and not the tt element, is the
   outermost element from which content style inheritance occurs.
 
--- a/ttml1/spec/ttml1.xml	Tue Aug 27 12:14:15 2013 -0600
+++ b/ttml1/spec/ttml1.xml	Tue Aug 27 12:30:56 2013 -0600
@@ -4278,6 +4278,10 @@
 then a presentation processor must interpret the attribute as if the closest supported value were
 specified.</p>
 <note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed font size and the supported font size is minimized.</p>
+</note>
+<note role="elaboration">
 <p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
 the <emph>cell</emph> length unit as defined by <specref ref="style-value-length"/>.
 When a single &lt;length&gt; is expressed using cell units, then it refers to the height of
@@ -6077,6 +6081,10 @@
 <p>If a presentation processor does not support a specific,
 valid opacity value, then it must interpret it as being equal to the
 closest supported value.</p>
+<note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed opacity and the supported opacity is minimized.</p>
+</note>
 </div3>
 <div3 id="style-value-color">
 <head>&lt;color&gt;</head>
@@ -6134,6 +6142,10 @@
 <p>If a presentation processor does not support a specific,
 valid color or alpha value, then it must interpret it as being equal
 to the closest supported value.</p>
+<note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed color or alpha and the supported color or alpha in the RGB color space is minimized.</p>
+</note>
 </div3>
 <div3 id="style-value-digit">
 <head>&lt;digit&gt;</head>
--- a/ttml2/spec/ttml2.xml	Tue Aug 27 12:14:15 2013 -0600
+++ b/ttml2/spec/ttml2.xml	Tue Aug 27 12:30:56 2013 -0600
@@ -4487,6 +4487,10 @@
 then a presentation processor must interpret the attribute as if the closest supported value were
 specified.</p>
 <note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed font size and the supported font size is minimized.</p>
+</note>
+<note role="elaboration">
 <p>The expression <code>1c</code> means one cell, where <code>'c'</code> expresses
 the <emph>cell</emph> length unit as defined by <specref ref="style-value-length"/>.
 When a single &lt;length&gt; is expressed using cell units, then it refers to the height of
@@ -6388,6 +6392,10 @@
 <p>If a presentation processor does not support a specific,
 valid opacity value, then it must interpret it as being equal to the
 closest supported value.</p>
+<note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed opacity and the supported opacity is minimized.</p>
+</note>
 </div3>
 
 <div3 id="style-value-border-color">
@@ -6520,6 +6528,10 @@
 <p>If a presentation processor does not support a specific,
 valid color or alpha value, then it must interpret it as being equal
 to the closest supported value.</p>
+<note role="elaboration">
+<p>In this context, the phrase <emph>closest supported value</emph> means the value for which the Euclidean distance between
+the computed color or alpha and the supported color or alpha in the RGB color space is minimized.</p>
+</note>
 </div3>
 <div3 id="style-value-digit">
 <head>&lt;digit&gt;</head>