[css-inline-3] initial letter is aligned using its top point when size < sink. w3c#5329

Author: fantasai

css-inline-3/Overview.bs

@@ -2151,18 +2151,34 @@ Block-axis Positioning and Kerning</h4>
 
 	In the <a>block axis</a>, the <a>initial letter</a> is positioned
 	with respect to the [=line box=] in which it [=originates=]
-	as required to satisfy its <a>under</a> alignment point ('initial-letter-align')
-	at its specified [=initial letter sink|sink=] ('initial-letter'),
-	i.e. it is positioned
+	as required to satisfy its alignment ('initial-letter-align')
+	and specified [=initial letter sink|sink=] ('initial-letter'):
+
+	* If its [=initial letter size|size=] is greater than or equal to
+		its [=initial letter sink|sink=],
+		[=the initial letter=] is positioned
+		to satisfy its <a>under</a> alignment,
+		and then shifted by
+		([=initial letter sink|sink=] - 1) &times; 'line-height' of [=containing block=]
+		towards the [=containing block=]’s [=block end=].
+
+	* If its [=initial letter size|size=] is less than
+		its [=initial letter sink|sink=],
+		[=the initial letter=] is positioned
+		to satisfy its <a>over</a> alignment.
+
+	Note: An [=initial letter=] is essentially positioned
 	such that it would sink the number of lines
 	specified by 'initial-letter'’s second argument
 	and align to the requisite <a>under</a> alignment point
 	if it was assumed that its containing block held only
 	the <a>initial letter</a> itself
 	followed by an infinite sequence of plain text
 	as the direct contents of its <a>root inline box</a>.
+	Its position is not affected by line height inconsistencies
+	introduced by the contents of the impacted line boxes.
 
-	 <figure>
+	<figure>
 		<img src="images/infinite-text.png" width="300"
 		     alt="Constant-sized text underlay shows how initial letter alignment
 		          is not affected by the content of the spanned lines.">