[css-inline-3] Add “fill line box” switch for inline boxes. w3c#1974

Author: fantasai

css-inline-3/Overview.bs

@@ -287,6 +287,51 @@ Alignment Shift: 'baseline-shift' longhand</h4>
 
 	Issue: We would prefer to remove this, and are looking for feedback from SVG user agents as to whether it's necessary.
 
+<h2 id="inline-box-dimensions">
+Drawing Inline Boxes</h2>
+
+<h3 id="line-fill">
+Inline Box Heights: the 'something-or-other' property</h3>
+
+	<pre class="propdef">
+	Name: something-or-other
+	Value: normal | fill
+	Initial: normal
+	Applies to: <a>inline boxes</a>
+	Inherited: no
+	Percentages: n/a
+	Computed value: as specified
+	</pre>
+
+	This property specifies how the <a>logical height</a>
+	of the <a>content area</a> of an <a>inline box</a>
+	is measured
+	and how it is aligned with its contents.
+	(It has no effect on the size or position of the box’s contents.)
+	Values have the following meanings:
+
+	<dl dfn-for="something-or-other" dfn-type=value>
+		<dt><dfn>normal</dfn>
+		<dd>
+			The <a>content area</a> of the <a>inline box</a>
+			is sized and position to fit its (possibly hypothetical) text
+			as specified in <a href="https://www.w3.org/TR/CSS2/visudet.html#inline-non-replaced">CSS2&sect;10.6.1</a>.
+
+		<dt><dfn>fill</dfn>
+		<dd>
+			The <a>logical height</a> of the <a>content area</a>
+			is calculated as the <a>stretch fit</a>
+			into the line box.
+			The box is then positioned such that its <a>margin edges</a>
+			coincide with the line box’s edges.
+	</dl>
+
+	Issue: We need a meaningful name for this property.
+
+	Issue: We might want to use this opportunity to more precisely define ''something-or-other/normal'',
+	rename it to match,
+	and possibly introduce any other values that may seem necessary.
+
 <h2 id="initial-letter-styling">
 <!--<a name="Initial"></a>-->
 Initial Letters</h2>