[css-inline-3] Add raise/drop keywords as syntactic sugar for '1' / omitted drop values. #2955

Author: fantasai

css-inline-3/Overview.bs

@@ -613,7 +613,7 @@ Creating Initial Letters: the 'initial-letters' property</h3>
 
 	<pre class="propdef">
 	Name: <dfn id="propdef-initial-letters">initial-letters</dfn>
-	Value: normal | [<<number>> <<integer>>?]
+	Value: normal | <<number>> <<integer>> | <<number>> && [ drop | raise ]?
 	Initial: normal
 	Applies to: certain inline-level boxes and <css>::first-letter</css> and inside <css>::marker</css> boxes (<a href="#first-most-inline-level">see prose</a>)
 	Inherited: no
@@ -625,7 +625,8 @@ Creating Initial Letters: the 'initial-letters' property</h3>
 	ISSUE: Renaming this property (and the others in this section)
 	is currently <a href="https://github.com/w3c/csswg-drafts/issues/2950">under discussion</a>.
 
-	This property specifies styling for dropped, raised, and sunken initial letters.
+	This property specifies styling for dropped, raised, and sunken initial letters
+	by specifying their <a lt="initial letter size">size</a> and <a lt="initial letter sink">sink</a>.
 	It takes the following values:
 
 	<dl dfn-for=initial-letters dfn-type=value>
@@ -648,10 +649,21 @@ Creating Initial Letters: the 'initial-letters' property</h3>
 			A value of ''1'' indicates a <a>raised initial</a>;
 			values greater than ''1'' indiciate a <a>sunken initial</a>.
 			Values less than one are invalid.
-			If omitted, it duplicates the first argument,
+
+		<dt><dfn>raise</dfn>
+		<dd>
+			Computes to an <a>initial letter sink</a> of ''1''.
+
+		<dt><dfn>drop</dfn>
+		<dd>
+			Computes to an <a>initial letter sink</a>
+			equal to the <a>initial letter size</a>
 			floored to the nearest positive whole number.
 	</dl>
 
+	If the <a>initial letter sink</a> value is omitted,
+	''drop'' is assumed.
+
 	An <dfn lt="initial letter | initial letter box">initial letter</dfn> is
 	an <a>in-flow</a> box
 	to which 'initial-letters' applies and is not ''initial-letters/normal'';
@@ -662,7 +674,9 @@ Creating Initial Letters: the 'initial-letters' property</h3>
 
 		<dl>
 			<dt>''initial-letters: 3''
-			<dt>(''initial-letters: 3 3'')
+			<dt>''initial-letters: 3 3''
+			<dt>''initial-letters: 3 drop''
+			<dt>''initial-letters: drop 3''
 			<dd>
 				Represents a <a>dropped initial</a> 3 lines high, 3 lines deep.
 
@@ -677,6 +691,8 @@ Creating Initial Letters: the 'initial-letters' property</h3>
 					alt="3 lines high, 2 lines deep">
 
 			<dt>''initial-letters: 3 1''
+			<dt>''initial-letters: 3 raise''
+			<dt>''initial-letters: raise 3''
 			<dd>
 				Represents a <a>raised initial</a> 3 lines high, 1 line deep.