[css-inline-3] non-zero borders/padding blocks leading-trim. w3c#5237

Author: fantasai

css-inline-3/Overview.bs

@@ -1300,7 +1300,7 @@ Half-Leading Control: the 'leading-trim' property</h3>
 	On [=block containers=],
 	specifies whether to trim [=half-leading=]
 	at the start/end of its content
-	to the corresponding 'text-edge' metric of its [=root inline box=]
+	to the corresponding 'text-edge' metric
 	to better match the box’s [=content edge=] to its text content.
 
 	This property has no effect when 'text-edge' is ''text-edge/leading''.
@@ -1324,7 +1324,9 @@ Half-Leading Control: the 'leading-trim' property</h3>
 			For [=block containers=]:
 			trim the [=block-start=] side of the <a>first formatted line</a>
 			to the corresponding 'text-edge' metric of its [=root inline box=].
-			(If there is no such line, there is no effect.)
+			If there is no such line,
+			or if there is intervening non-zero padding or borders,
+			there is no effect.
 
 			For [=inline boxes=]:
 			trims the [=block-end=] side of the box
@@ -1336,7 +1338,9 @@ Half-Leading Control: the 'leading-trim' property</h3>
 			For [=block containers=]:
 			trim the [=block-end=] side of the last formatted line
 			to the corresponding 'text-edge' metric of its [=root inline box=].
-			(If there is no such line, there is no effect.)
+			If there is no such line,
+			or if there is intervening non-zero padding or borders,
+			there is no effect.
 
 			For [=inline boxes=]:
 			trims the [=block-end=] side of the box
@@ -2916,6 +2920,9 @@ Changes</h2>
 		to handle common practices for certain Indic scripts.
 		See <a href="https://www.w3.org/TR/ilreq/#h_scripts_without_hanging_baseline">Indic Layout Requirements</a>.
 		(<a href="https://github.com/w3c/csswg-drafts/issues/864">Issue 864</a>)
+
+		<li>Make non-zero padding and border block effects of 'leading-trim' from ancestors.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/5237">Issue 5237</a>)
 	</ul>
 
 	Changes since the