[css-ruby] inter-character annotations only happen in horizontal text

Author: frivoal

css-ruby-1/Overview.bs

@@ -740,8 +740,9 @@ Ruby Layout</h2>
 <h3 id="inter-character-layout">
 Inter-character Ruby Layout</h3>
 
-	Inter-character annotations have special layout.
-	When 'ruby-position' indicates ''inter-character'' annotations,
+	[=Inter-character annotations=] have special layout.
+	In [=horizontal writing mode=],
+	when the value 'ruby-position' is ''inter-character'',
 	the affected [=ruby annotation boxes=]
 	are spliced into and measured as part of the layout of the [=base level=].
 	The [=ruby base container=] must be sized to include both the [=ruby base boxes=]
@@ -750,9 +751,9 @@ Inter-character Ruby Layout</h3>
 	so that its content box coincides with that of the [=ruby base container=].
 
 	For the purpose of laying out other levels of annotations,
-	an ''inter-character'' annotation effectively becomes part of its base.
+	an [=inter-character annotation=] effectively becomes part of its base.
 	<span class="issue">Or should it become a quasi-base between two bases?</span>
-	A spanning ''inter-character'' annotation is placed after
+	A spanning [=inter-character annotation=] is placed after
 	all the bases that it spans.
 
 <h3 id="box-style">
@@ -799,7 +800,7 @@ Breaking Across Lines</h3>
 	Whenever ruby breaks across lines, [=ruby annotations=] must stay
 	with their respective [=ruby bases=].
 	The line <em>must not</em> break between a [=ruby base=] and its [=annotations=],
-	even in the case of ''inter-character'' [=annotations=].
+	even in the case of [=inter-character annotations=].
 
 	<div class="figure">
 		<img src="images/r-break-b.gif"
@@ -867,7 +868,7 @@ Breaking Within Bases</h4>
 	but it is recommended that the UA attempt to proportionally balance
 	the amount of content inside each fragment.
 
-	There are no line breaking opportunities within ''inter-character'' [=annotations=].
+	There are no line breaking opportunities within [=inter-character annotations=].
 
 	Ruby alignment takes place within each fragment, after line-breaking.
 
@@ -1037,8 +1038,12 @@ Ruby Positioning: the 'ruby-position' property</h3>
 
 		<dt><dfn>inter-character</dfn></dt>
 		<dd>
+			If the [=writing mode=] of the enclosing [=ruby container=] is [=vertical writing mode|vertical=],
+			this value has the same effect as ''over''.
+
+			Otherwise, the ruby text becomes a <dfn dfn>inter-character annotation</dfn>.
 			The ruby text appears on the right of the base in horizontal text.
-			This value forces the computed value of 'writing-mode' of the [=ruby annotation container=] to be ''vertical-rl''.
+			This forces the computed value of 'writing-mode' of the [=ruby annotation container=] to be ''vertical-rl''.
 
 			This value is provided for the special case of traditional Chinese
 			as used especially in Taiwan: