[css-sizing-3] Defer 'stretch' and 'fit-content' to Level 4 per WG resolution.

Author: fantasai

css-sizing-3/Overview.bs

@@ -2,8 +2,8 @@
 Title: CSS Intrinsic & Extrinsic Sizing Module Level 3
 Shortname: css-sizing
 Level: 3
-Status: WD
-Work Status: Revising
+Status: ED
+Work Status: Refining
 Group: csswg
 ED: https://drafts.csswg.org/css-sizing-3/
 TR: https://www.w3.org/TR/css-sizing-3/
@@ -146,14 +146,20 @@ Auto Box Sizes</h3>
 		: <dfn>stretch-fit size</dfn>
 		: <dfn>stretch-fit inline size</dfn>
 		: <dfn>stretch-fit block size</dfn>
-		:: Roughly, the <a>size</a> a box would take
-			if it filled the <a>available space</a>
-			in the given axis.
-			(See [[#extrinsic]].)
+		:: The <a>size</a> a box would take
+			if its <a>outer size</a> filled the <a>available space</a>
+			in the given axis;
+			in other words, the <a>stretch fit</a> into the <a>available space</a>,
+			if that is <a>definite</a>.
+			Undefined if the <a>available space</a> is <a>indefinite</a>.
 
 			Note: For the <a>inline axis</a>, this is called the “available width” in <a href="https://www.w3.org/TR/CSS2/visudet.html#float-width">CSS2.1§10.3.5</a>
 			and computed by the rules in <a href="https://www.w3.org/TR/CSS2/visudet.html#blockwidth">CSS2.1§10.3.3</a>.
 
+			Note: Calculations involving this size need to specify a fallback behavior
+			for when the <a>available space</a> is <a>indefinite</a>
+			if that happens to be possible.
+
 		: <dfn lt="max-content | max-content size">max-content size</dfn>
 		:: A box’s “ideal” <a>size</a> in a given axis when given infinite available space.
 			Usually this is the smallest <a>size</a> the box could take in that axis
@@ -247,7 +253,7 @@ New Keywords for 'width' and 'height'</h3>
 
 	<pre class=propdef partial>
 	Name: width, max-width, height, max-height
-	New values: stretch | max-content | min-content | fit-content | fit-content(<<length-percentage>>)
+	New values: max-content | min-content | fit-content(<<length-percentage>>)
 	</pre>
 
 	<pre class=propdef partial>
@@ -260,6 +266,7 @@ New Keywords for 'width' and 'height'</h3>
 		defined above):
 
 	<dl dfn-type=value dfn-for="width, min-width, max-width, height, min-height, max-height">
+<!--
 		<dt><dfn for="width, max-width, height, max-height">stretch</dfn>
 		<dd>
 			If 'align-self' or 'justify-self' (as appropriate to the relevant axis)
@@ -275,6 +282,7 @@ New Keywords for 'width' and 'height'</h3>
 			for non-replaced blocks in normal flow, see <a href="https://www.w3.org/TR/CSS2/visudet.html#blockwidth">CSS2.1§10.3.3</a>.
 			It allows re-using this formula for boxes that are otherwise shrink-wrapped,
 			like tables.
+-->
 
 		<dt><dfn>max-content</dfn>
 		<dd>
@@ -287,15 +295,15 @@ New Keywords for 'width' and 'height'</h3>
 			If specified for the inline axis,
 			use the <a>min-content inline size</a>;
 			otherwise compute to the property’s <a>initial value</a>.
-
+<!--
 		<dt><dfn for="width, max-width, height, max-height">fit-content</dfn>
 		<dd>
 			If specified for the inline axis,
 			use the <a>fit-content inline size</a>
 			i.e.
 			<code>min(''width/max-content'', max(''width/min-content'', ''width/stretch''))</code>;
 			otherwise compute to the property’s <a>initial value</a>.
-
+-->
 		<dt><dfn for="width, max-width, height, max-height">fit-content(<<length-percentage>>)</dfn>
 		<dd>
 			If specified for the inline axis,
@@ -306,24 +314,39 @@ New Keywords for 'width' and 'height'</h3>
 			otherwise compute to the property’s <a>initial value</a>.
 	</dl>
 
-	Issue: Is ''width/stretch'' stable enough or should we defer to L4?
+	Note: This section previously defined ''width/stretch'' and ''width/fit-content''
+	as keywords representing the <a>stretch-fit size</a> and <a>fit-content size</a>,
+	respectively.
+	These keywords have been deferred to Level 4
+	(along with an additional ''width/contain'' keyword that
+	behaves similarly to ''width/stretch''
+	but preserves the intrinsic aspect ratio, if any)
+	to better work out the implications in situations with
+	<a>indefinite</a> <a>available space</a>.
 
 	Note: To size an element such that it avoids overlapping sibling floats,
 	make sure it's a <a>formatting context</a> root.
 	For some layout modes, such as Grid and Flexbox,
 	this is true automatically.
 	For Block layout, this means using ''display: flow-root;''.
 
+<h4 id="behave-auto">
+“Behaving as ''width/auto''”</h4>
+
+<!-- THIS NEED SOME THINKING THROUGH, WE DID WEIRD THINGS WITH FLEXBOX/GRID
 	Note: Percentages resolved against the intrinsic sizes
 	(''width/max-content'', ''width/min-content'', ''width/fit-content'')
 	will behave as ''width/auto''.
+-->
 	<!-- <a href="https://www.w3.org/TR/CSS2/visudet.html#the-height-property">as defined by CSS 2</a>. [[!CSS2]] -->
 	<!-- Restore the above when 2.1 is updated and published with the new "behaves as" text we resolved on. -->
 
 	To have a common term for both when
 	'width'/'height' computes to ''width/auto''
-	and when it is defined to behave as ''width/auto''
-	(as in the case above),
+	and when it is defined to behave as if ''width/auto'' were specified
+	(as in the case of <a href="https://www.w3.org/TR/CSS2/visudet.html#the-height-property">block percentage heights</a>
+	resolving against an <a>indefinite</a> size,
+	see <a href="https://www.w3.org/TR/CSS2/visudet.html#the-height-property">CSS2&sect;10.5</a>),
 	the property is said to <dfn export lt="behave as auto|behaves as auto|behaving as auto">behave as auto</dfn>
 	in both of these cases.
 
@@ -346,35 +369,42 @@ Column Sizing Keywords</h3>
 
 	<pre class="propdef partial">
 	Name: column-width
-	New values: stretch | max-content | min-content | fit-content | fit-content(<<length-percentage>>)
+	New values: max-content | min-content | fit-content(<<length-percentage>>)
 	</pre>
 
 	<p>When  used as values for 'column-width',
 		the new keywords specify the optimal column width:
 
 	<dl dfn-type=value dfn-for="column-width">
+<!--
 		<dt><dfn>stretch</dfn>
 		<dd>Specifies the optimal column width as the <a>stretch-fit inline size</a>
 			of the multi-column element.
-
+-->
 		<dt><dfn>max-content</dfn>
 		<dd>Specifies the optimal column width as the <a>max-content inline size</a>
 			of the multi-column element's contents.
 
 		<dt><dfn>min-content</dfn>
 		<dd>Specifies the optimal column width as the <a>min-content inline size</a>
 			of the multi-column element's contents.
-
+<!--
 		<dt><dfn>fit-content</dfn>
 		<dd>Specifies the optimal column width as
 			<code>min(<a>max-content inline size</a>, max(<a>min-content inline size</a>, <a>stretch-fit inline size</a>))</code>.
-
+-->
 		<dt><dfn>fit-content(<<length-percentage>>)</dfn>
 		<dd>
 			Specifies the optimal column width as
 			<code>min(<a>max-content size</a>, max(<a>min-content size</a>, <<length-percentage>>))</code>
 	</dl>
 
+	Note: The column width does not vary by column.
+	When the column width is informed by the multi-column element's contents
+	(as in the keywords above),
+	all of its contents are taken under consideration
+	and the calculated width is shared by all the columns.
+
 <h2 id='intrinsic'>
 Intrinsic Size Determination</h2>
 
@@ -672,8 +702,8 @@ Changes</h2>
 		<li>Compute new keywords to the initial value, not to a potentially non-existent ''width/auto'', when applied to the block axis.
 		<li>Specify that percent sizes on replaced elements zero out their min-content contribution.
 		<li>Fix confusing/wrong definition of percentage sizes resolved against a dependent containing block.
-		<li>
-		  ISSUE: Drop ''width/stretch'' for now?
+		<li>Deferred the ''width/stretch'' and ''width/fit-content'' keywords to Level 4
+			to allow for further consideration of their behavior in <a>indefinite</a> containing blocks.
 	</ul>
 
 <h2 class=no-num id="acknowledgments">