[css-text] Simplify letter-spacing: normal definition per <http://lists.w3.org/Archives/Public/www-style/2013Aug/0212.html>

Author: fantasai

css-ruby/Overview.src.html

@@ -3,6 +3,7 @@
 Issues:
 	bidi
 	box layout/sizing
+	clean up inter-character vs. parallel layout requirements
 
 Redo all examples with consistent font. (M+ 2p?)
 
@@ -614,10 +615,92 @@ <h4 id="break-between">
 <h4 id="break-within">
 Breaking within bases</h4>
 
-	<p class="issue">Fill in this section...
+	<p>For longer base texts, it is sometimes appropriate to allow breaking within a base-annotation pair.
+	For example, if an English sentence is annotated with its Japanese translation,
+	allowing the text to wrap allows for reasonable line breaking behavior in the paragraph.
+
+	<p class="issue">
+	Insert scanned example so people don't think this is just the ramblings of an insane spec-writer.
+
+	<p>Line-breaking within a <i>ruby base</i> is only allowed if the 'white-space' property
+	of the <i>ruby base</i> and all its parallel <i>annotations</i> allow it,
+	and there exists a <i>soft wrap opportunity</i> <em>within</em> (i.e. not at the start or end)
+	the content of each base/annotation box.
+	Since there is no structural correspondance between fragments of content
+	within <i>ruby bases</i> and <i>annotations</i>,
+	the UA may break at any set of opportunities;
+	but it is recommended that the UA attempt to proportionally balance
+	the amount of content inside each fragment.
 
 	<p>There are no line breaking opportunities within ''inter-character'' <i>annotations</i>.
 
+	<p>Ruby alignment takes place within each fragment, after line-breaking.
+
+<h3 id="ruby-bidi">
+Bidi Reordering</h3>
+
+	<p class="issue">The easiest thing would be to treat each <i>ruby base</i> as an embedding of its 'direction'.
+	But this means that implicit bidi reordering is scoped to within a single base.
+
+	<p>The Unicode bidirectional algorithm orders logically-stored text for visual presentation
+	when characters from scripts of opposing directionalities are mixed
+	within a single paragraph.
+	(See [[CSS3-WRITING-MODES]] for a more in-depth discussion of bidirectional text in CSS.)
+	Bidi reordering of ruby-annotation pairs is controlled by the ordering of the base text, as follows:
+
+<h4 id="bidi-B">Proposal B</h4>
+
+	<p class="note">This proposal is simpler, but will require more frequent tagging of mixed-directionality content.
+
+	<p>To avoid the interference of the <i>annotations</i> in the ordering of base text,
+	all annotations are ignored for the purpose of resolving neutral characters in the base level.
+
+	<p>To preserve the correspondance of <i>ruby annotations</i>
+	to their respective <i>ruby bases</i>,
+	a few restrictions are imposed:
+	<ul>
+		<li>The contents of a <i>ruby base</i> must remain contiguous.
+			To this end, the contents of 
+		<li>All <i>bases</i> spanned by a single <i>annotation</i> must remain contiguous.
+	</ul>
+
+		<li>When a <i>ruby base</i> is moved due to bidi reordering,
+			all of its corresponding <i>ruby annotations</i> must follow.
+
+<h4 id="bidi-B">Proposal B</h4>
+
+	<p class="note">This preserves some aspects of implicit bidi.
+	For example, annotating each half of "first-second" would not cause the word to reverse itself to "second-first" within an opposite-order paragraph.
+
+	<p>To avoid the interference of the <i>annotations</i> in the ordering of the base text,
+	all annotations are ignored for the purpose of resolving neutral characters in the base text;
+	and the base text is resolved exactly as if each <i>ruby base</i> were
+	just a normal <i>inline box</i> embedded in the <i>ruby container</i>'s inline formatting context.
+
+	<p>Furthermore, to preserve the correspondance of <i>ruby annotations</i>
+	to their respective <i>ruby bases</i>,
+	a few restrictions are imposed:
+	<ul>
+		<li>
+		<li>The contents of a <i>ruby base</i> must remain contiguous.
+		<li>All <i>bases</i> spanned by a single <i>annotation</i> must remain contiguous.
+	</ul>
+	<p>To this end, the text of <i>ruby base</i> boxes that are not <i>bidi-isolated</i>
+	must have its embedding level increased by two;
+	and if an <i>annotation</i> spans more than one <i>ruby base</i>,
+	the spanned text's embedding level
+	(or the embedding level assigned to the isolation, if the <i>ruby base</i> is <i>bidi-isolated</i>)
+	is further increased by two.
+
+	<p>
+
+<!--
+	<p>
+	Each <i>ruby base</i> within a <i>ruby container</i> is treated
+	as a strong character with the directionality of its 'direction' property.
+	When resolving the embedding levels of 
+-->
+
 <h3 id="line-height">
 Ruby box and line stacking</h3>