[css-multicol] The column-gap property is now defined in CSS-ALIGN. Fixes #3641

Author: rachelandrew

css-multicol-1/Overview.bs

@@ -26,6 +26,8 @@ Link Defaults: css-color (property) color, css2 (property) max-height, css-backg
 <pre class="link-defaults">
 spec:css-sizing-3; type:property; text:min-height
 spec:css-break-4; type:dfn; text:fragment
+spec:css-align-3; type:property; text:column-gap
+spec:css-align-3; type:value; for:column-gap; text:normal
 </pre>
 
 <style type="text/css">
@@ -713,16 +715,13 @@ Column gaps and rules</h2>
 <h3 id='cg'>
 'column-gap'</h3>
 
-	<pre class=propdef>
-	Name: column-gap
-	Value: <<length-percentage>> | normal
-	Initial: normal
-	Applies to: <a>multicol containers</a>
-	Inherited: no
-	Percentages: refer to the content width of the multi-column container
-	Computed value: the keyword ''column-gap/normal'' or a computed <<length-percentage>> value
-	Animation type: by computed value type
-	</pre>
+	The 'column-gap' property is defined in [[!CSS3-ALIGN]].
+
+	In a [=multi-column formatting context=] 
+	the used value of ''normal'' for the 'column-gap' property is ''1em''. 
+	This ensures columns are readable when the initial values are used.
+	If there is a column rule between columns, 
+	it will appear in the middle of the gap.
 
 	<wpt>
 	multicol-gap-animation-001.html
@@ -733,40 +732,13 @@ Column gaps and rules</h2>
 	multicol-gap-large-001.xht
 	multicol-gap-large-002.xht
 	multicol-gap-negative-001.xht
+	multicol-gap-000.xht
+	multicol-gap-002.xht
+	multicol-gap-percentage-001.html
+	multicol-gap-001.xht
+	multicol-gap-003.xht
 	</wpt>
 
-	<i>'column-gap' accepting <<length-percentage>> is at risk,
-	and may be reverted to <<length>>.</i>
-
-	<dl dfn-type=value dfn-for=column-gap>
-		<dt><dfn><<length-percentage>></dfn>
-		<dd>
-			Specifies the gap between columns.
-			If there is a column rule between columns,
-			it will appear in the middle of the gap.
-
-			The <<length>> or <<percentage>> cannot be negative.
-
-			<wpt>
-			multicol-gap-000.xht
-			multicol-gap-002.xht
-			multicol-gap-percentage-001.html
-			</wpt>
-
-		<dt><dfn>normal</dfn>
-		<dd>
-			Identical to <a value for="column-gap">&lt;length-percentage></a>,
-			but with a used value of ''1em''.
-
-			<wpt>
-			multicol-gap-001.xht
-			multicol-gap-003.xht
-			</wpt>
-	</dl>
-
-	
-
-
 <h3 id='crc'>
 'column-rule-color'</h3>
 
@@ -1434,6 +1406,8 @@ This appendix is <em>informative</em>.
 
 <h3 id="changes-from-20180528">Changes from the <a href="https://www.w3.org/TR/2018/WD-css-multicol-1-20180528/">Working Draft (WD) of 28 May 2018</a></h3>
 <ul>
+	<li>Moved the definition of the 'column-gap' property to [[CSS3-ALIGN]] and added a paragraph detailing the specifics of 'column-gap' in multicol:
+	<br />"In a multi-column formatting context the used value of normal for the column-gap property is 1em. This ensures columns are readable when the initial values are used. If there is a column rule between columns, it will appear in the middle of the gap." <a href="https://github.com/w3c/csswg-drafts/issues/3641">Resolved 4 June 2019.</a></li>
 	<li>Reworded the section <a href="#the-multi-column-model">The multi-column model</a>, based on input from Morten Stenshorne in <a href="https://github.com/w3c/csswg-drafts/issues/2203#issuecomment-431695940">issue 2203</a>.</li>
 	<li>Removed the at-risk marker from the length-percentage value for 'column-gap'. <a href="https://github.com/w3c/csswg-drafts/issues/3988">Resolved 4 June 2019.</a></li>
 	<li>Added the paragraph "In continuous contexts, this property will only be consulted if the length of columns has been constrained in the block dimension, including min and max constraints (e.g., 'height', 'min-height', 'max-height'). Otherwise, columns will automatically be balanced." This paragraph (without the additional detail regarding min and max constraints) was commented out in 2012, causing an interoperability issue. Also corrected the example of content ending up all in the first column, by adding the height constraint. Resolved <a href="https://github.com/w3c/csswg-drafts/issues/3224#issuecomment-468089503">28 February 2019</a></li>
@@ -1443,6 +1417,7 @@ This appendix is <em>informative</em>.
 </ul>
 
 <h3 id="changes-from-20171005">Changes from the <a href="https://www.w3.org/TR/2017/WD-css-multicol-1-20171005/">Working Draft (WD) of 5 October 2017</a></h3>
+<ul>
 	<li>Changed references to paged media to refer to fragmented contexts. Resolved <a href="https://github.com/w3c/csswg-drafts/issues/1746#issuecomment-380731574">12 Apr 2018</a>.</li>
 	<li>Changed a line regarding the <code>column-fill</code> property:
 	<br><q>In continuous media, this property does not have any effect in