[css-ruby] Details on inter-character ruby layout

Author: frivoal

css-ruby-1/Overview.bs

@@ -19,6 +19,7 @@ Abstract: This module describes the rendering model and formatting controls rela
 </pre>
 <pre class=link-defaults>
 spec:css-text-3; type:dfn; text:character
+spec:css-box-4; type:dfn; text:content area
 </pre>
 
 
@@ -440,10 +441,10 @@ Annotation Pairing</h3>
 	However, if there are multiple [=annotation levels=],
 	it can be associated with multiple [=ruby annotations=].
 
-	Once [=pairing=] is complete, <dfn local-lt=column>ruby column</dfn> units are defined,
+	Once [=pairing=] is complete, <dfn local-lt=column>ruby columns</dfn> are defined,
 	each represented by a single [=ruby base=]
 	and one [=ruby annotation=] (possibly an empty, anonymous one)
-	from each [=annotation level=] in its [=ruby segment=].
+	from each [=interlinear=] [=annotation level=] in its [=ruby segment=].
 
 <h4 id="segment-pairing">
 Segment Pairing and Annotation Levels</h4>
@@ -692,7 +693,7 @@ Ruby Layout</h2>
 	it is sized and positioned
 	as if it contained a single empty [=ruby base=].)
 
-	[=Inter-linear=] [=ruby annotations=] within a level
+	[=Interlinear=] [=ruby annotations=] within a level
 	are aligned to each other in the block axis
 	as if they were [=inline boxes=]
 	participating in the same [=inline formatting context=],
@@ -772,20 +773,59 @@ Ruby Layout</h2>
 Inter-character Ruby Layout</h3>
 
 	[=Inter-character annotations=] have special layout.
-	In [=horizontal writing mode=],
-	when the value 'ruby-position' is ''inter-character'',
-	the affected [=ruby annotation boxes=]
+	[=Inter-character=] [=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=]
-	as well as the ''inter-character'' [=ruby annotation boxes=].
-	The affected [=ruby annotation container=] is similarly sized
-	so that its content box coincides with that of the [=ruby base container=].
+	Each [=ruby annotation=] is inserted to the right of the [=ruby base=] it is paired with;
+	a [=spanning=] [=inter-character annotation=] is placed after
+	the rightmost of all the bases that it spans.
+	[=Inter-character=] [=ruby annotations=] are laid out
+	exactly like [=inline blocks=],
+	except as described below.
+
+	Note: As per the definition of ''inter-character'',
+	[=inter-character annotations=] always have a ''vertical-rl'' 'writing-mode',
+	and only exist in [=horizontal writing mode|horizontal=] [=ruby containers=].
+
+	Each [=ruby annotation=] is placed immediately to the right of the relevant [=ruby base=],
+	before any [=inter-base white space=] (or [=inter-segment white space=]).
+	If multiple [=inter-character=] [=ruby annotation boxes=] are placed against the same [=ruby base=],
+	their [=margin boxes=] are stacked rightwards without intervening space,
+	in increasing [=level=] order.
+
+	If the [=automatic size|automatic height=] of the [=ruby annotation box=]’s [=content area=]
+	would be shorter than the height of the [=content box=]
+	of the [=ruby base=] after which it is placed,
+	its [=content box=] height is increased to match that height exactly.
+
+	The alignment of the [=ruby annotation box=]
+	depends on the 'ruby-align' property on the [=ruby annotation=]:
+
+	<ul>
+		<li>
+			If 'ruby-align' is ''ruby-align/start'',
+			the top edge of the [=ruby annotation=]'s [=content box=] is aligned
+			with the top edge of the [=ruby base=]'s [=content box=].
+
+			<li>
+				Otherwise,
+				the center of the [=ruby annotation=]'s [=content box=] is vertically aligned
+				with the center of the [=ruby base=]'s [=content box=].
+	</ul>
+
+	The [=ruby annotation container box=] of an [=inter-character=] annotation
+	is sized and placed so that its content box coincides exactly with that of the [=ruby base container box=].
+
+	Note: The size and position of [=inter-character=] [=ruby annotation container boxes=]
+	has no effect on layout.
+	The above definition is merely so that programmatically inquiring about them
+	produces deterministic results.
+
+	For the purpose of [[#ruby-align-property|alignment]]
+	and column sizing (as discussed in [[#ruby-layout]]),
+	[=inter-character=] [=ruby annotations=] are not considered
+	to be part of the same [=column=] as the base to with they are attached;
+	rather, they effectively form a [=column=] of their own.
 
-	For the purpose of laying out other levels of annotations,
-	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
-	all the bases that it spans.
 
 <h3 id="box-style">
 Styling Ruby Boxes</h3>
@@ -1108,9 +1148,8 @@ Ruby Positioning: the 'ruby-position' property</h3>
 	are called <dfn local-lt="interlinear">interlinear annotations</dfn>.
 
 	If multiple [=ruby annotation containers=] have the same 'ruby-position',
-	they stack along the block axis for [=interlinear annotations=],
-	and along the inline axis for [=inter-character annotations=],
-	with lower levels of annotation closer to the base text.
+	they stack outwards from the base text.
+
 
 <h3 id="collapsed-ruby">
 Sharing Annotation Space: the 'ruby-merge' property</h3>
@@ -1212,8 +1251,11 @@ Ruby Text Distribution: the 'ruby-align' property</h3>
 	Note that space distributed by 'ruby-align' is unrelated to, and independent of,
 	any space distributed due to justification.
 
-	Note: It is the content within the boxes that is aligned in the excess space,
-	not the boxes themselves.
+	For [=inter-character=] annotations,
+	this property can also affect the alignment of the box itself
+	(see [[#inter-character-layout]]).
+	It otherwise only affects the alignment of content within the box,
+	not the size or position of the box itself.
 
 	Values have the following meanings:
 	<dl dfn-for=ruby-align dfn-type=value>