[css-inline-3] Editorial clean-up; fix integration of leading-trim/text-edge

Author: fantasai

css-inline-3/Overview.bs

@@ -940,11 +940,12 @@ Line Spacing: the 'line-height' property</h3>
 	Animation type: by computed value type
 	</pre>
 
-	This property specifies the <dfn>preferred line height</dfn>:
-	the [=logical height=] of the [=inline box=]
-	as used in the [[#line-layout|calculation of the line box height]].
+	This property specifies the box’s <dfn>preferred line height</dfn>,
+	which is used in calculating its “[=layout bounds=]”,
+	i.e. its contribution to the [=logical height=] of its [=line box=].
+	(See [[#inline-height]].)
 
-	Note: Because it inherits to the [=root inline box=]
+	Note: Because it applies to the [=root inline box=]
 	when specified on a [=block container=],
 	'line-height' effectively establishes
 	the minimum height of the block’s [=line boxes=].
@@ -956,11 +957,10 @@ Line Spacing: the 'line-height' property</h3>
 		<dd>
 			Determine the [=preferred line height=]
 			automatically based on font metrics.
-			See [[#inline-height]].
 
 		<dt><dfn><<length>></dfn>
 		<dd>
-			The specified length is used as the [=preferred line height=]
+			The specified length is used as the [=preferred line height=].
 			Negative values are illegal.
 
 		<dt><dfn><<number>></dfn>
@@ -978,9 +978,9 @@ Line Spacing: the 'line-height' property</h3>
 			Negative values are illegal.
 	</dl>
 
-	Note: Glyphs from fonts other than the [=first available font=]
-	do not impact the [=layout bounds=] or [=baseline=] position
-	of an [=inline box=] with a non-''line-height/normal'' 'line-height'.
+	Note: Metrics from fonts other than the [=first available font=]
+	only impact the [=layout bounds=]
+	of an [=inline box=] with ''line-height: normal''.
 
 	<div class="example">
 		The three rules in the example below have the same used line height:
@@ -1002,9 +1002,10 @@ Line Spacing: the 'line-height' property</h3>
 	See also <a href="https://github.com/w3c/csswg-drafts/issues/3118">Issue 3118</a>
 	and <a href="https://github.com/w3c/csswg-drafts/issues/2165">Issue 2165</a>.
 
-	Note: Although margins, borders, and padding of [=inline boxes=]
-	do not enter into the line height calculation,
-	they are still rendered around these boxes.
+	Note: When 'text-edge' is ''text-edge/leading'',
+	the margins, borders, and padding of [=inline boxes=]
+	do not affect the line box’s height calculation.
+	However, they are still rendered around these boxes.
 	This means that if the size specified by 'line-height'
 	is less than the size of the box,
 	backgrounds and borders can “bleed” into adjoining line boxes,
@@ -1024,7 +1025,6 @@ Inline Box Edge Metrics: the 'text-edge' property</h3>
 	Animation type: discrete
 	</pre>
 
-
 	ISSUE: This is an early draft of a proposal,
 	and might change significantly
 	as design critiques and use cases are registered
@@ -1035,13 +1035,14 @@ Inline Box Edge Metrics: the 'text-edge' property</h3>
 	are sized in the [=block axis=] based on their font metrics.
 	The 'text-edge' property controls which metrics are used.
 
-	This property defines which metric is used
-	as the basis for the [=over=] and [=under=] edges
-	of the [=layout bounds=] of the [=inline box=].
-	The 'leading-trim' property can be used
+	The chosen metrics are used as the basis
+	for the [=layout bounds=] of the [=inline box=]
+	(if it is not the [=root inline box=]).
+	The 'leading-trim' property can be used in conjunction
 	to match the [=content edges=] to these same metrics.
-	The first value specifies the <dfn>text over edge</dfn>;
-	the second value specifies the <dfn>text under edge</dfn>.
+
+	The first value specifies the text [=over=] edge;
+	the second value specifies the text [=under=] edge.
 	If only one value is specified,
 	both edges are assigned that same keyword if possible;
 	else ''text-edge/text'' is assumed as the missing value.
@@ -1054,7 +1055,7 @@ Inline Box Edge Metrics: the 'text-edge' property</h3>
 	caused by ascents above the specified metrics
 	(such as for diacritics),
 	so authors using these values need to be careful
-	to provide sufficient spacing above the line.
+	to provide sufficient spacing for the text.
 
 	Values have the following meanings:
 
@@ -1095,7 +1096,7 @@ Inline Box Edge Metrics: the 'text-edge' property</h3>
 	Unless 'text-edge' is ''text-edge/leading''--
 	in which case the box’s own 'line-height' is used to add spacing--
 	the box’s margin, padding, and border also contribute
-	to the size of the [=line box=].
+	to the [=layout bounds=].
 
 	<figure>
 		<img src="images/text-edge.png" width="480"
@@ -1163,14 +1164,14 @@ Calculating the Logical Height Contributions (“Layout Bounds”) of Inline Box
 	may also be incorporated into <var>A</var> and <var>D</var>
 	by adding half to each side as [=half-leading=].
 
-	When its computed 'line-height' is ''line-height/normal'',
+	<strong>When its computed 'line-height' is ''line-height/normal''</strong>,
 	the [=layout bounds=] of an inline box encloses all its glyphs,
 	going from the highest <var>A</var> to the deepest <var>D</var>.
 	(Note that glyphs in a single box
 	can come from different fonts
 	and thus might not all have the same <var>A</var> and <var>D</var>.)
 
-	When its computed 'line-height' is not ''line-height/normal'',
+	<strong>When its computed 'line-height' is not ''line-height/normal''</strong>,
 	its [=layout bounds=] are derived solely from
 	metrics of its [=first available font=]
 	(ignoring glyphs from other fonts),
@@ -1210,26 +1211,24 @@ Half-Leading Control: the 'leading-trim' property</h3>
 
 	To ensure consistent spacing in the basic case of running text,
 	CSS line layout introduces leading both above and below
-	the text content of each line.
+	the text content of each line
+	as needed to ensure its 'line-height'.
 	In addition, the ascent and descent font metrics themselves
-	include extra space above and below the most common glyph sizes
+	often include extra space above and below the most typical glyph shapes
 	in order to accommodate occasional characters and diacritics
-	which ascend or descend beyond the typical bounds.
-	This prevents subsequent lines of text from overlapping each other.
+	that ascend or descend beyond the typical bounds.
+	This prevents adjacent lines of text from overlapping each other.
 	However, all this extra spacing interferes with visual alignment
 	and with control over effective (visually-apparent) spacing.
 
-	The 'leading-trim' properties allow controlling the spacing above and below
-	the first and last lines of a block.
-	It allows precise control over spacing;
-	moreover, by relying on font metrics rather than hard-coded lengths,
+	The 'leading-trim' property allows trimming
+	this additional space above and below
+	the first and last lines of a block,
+	allowing more precise control over spacing around the glyphs.
+	Moreover, by relying on font metrics rather than hard-coded lengths,
 	it allows content to be resized, rewrapped, and rendered in a variety of fonts
 	while maintaining that spacing.
 
-	Note: Content and ink overflowing a box
-	due to non-initial values of 'leading-trim'
-	is handled the same as content that would overflow the box or line box otherwise.
-
 	<div class="example">
 		<!-- Example from Weston Thayer in https://github.com/w3c/csswg-drafts/issues/3240#issuecomment-432375650 -->
 
@@ -1323,6 +1322,10 @@ Half-Leading Control: the 'leading-trim' property</h3>
 	to the corresponding 'text-edge' metric
 	to better match the box’s [=content edge=] to its text content.
 
+	Note: Content and ink overflowing a box
+	due to non-initial values of 'leading-trim'
+	is handled the same as content that would overflow the box or line box otherwise.
+
 	This property has no effect when 'text-edge' is ''text-edge/leading''.
 
 	Values have the following meanings: