[css-grid-2] Handle intrinsic size contribution to flexible tracks instead of ignoring their contents completely. #2177

Author: fantasai

css-grid-1/Overview.bs

@@ -3789,7 +3789,8 @@ Resolve Intrinsic Track Sizes</h3>
 
 		<li id="algo-single-span-items">
 			<strong>Size tracks to fit non-spanning items:</strong>
-			For each track with an intrinsic <a>track sizing function</a>,
+			For each track with an intrinsic <a>track sizing function</a>
+			and not a <a>flexible sizing function</a>,
 			consider the items in it with a span of 1:
 
 			<dl class="switch">
@@ -3847,7 +3848,7 @@ Resolve Intrinsic Track Sizes</h3>
 			increase the <a>growth limit</a> to match the <a>base size</a>.
 
 		<li id="algo-spanning-items">
-			<strong>Increase sizes to accommodate spanning items:</strong>
+			<strong>Increase sizes to accommodate spanning items crossing content-sized tracks:</strong>
 			Next, consider the items with a span of 2
 			that do not span a track with a <a>flexible sizing function</a>,
 			treating a <a>min track sizing function</a> of ''auto''
@@ -3939,6 +3940,27 @@ Resolve Intrinsic Track Sizes</h3>
 
 			Repeat incrementally for items with greater spans until all items have been considered.
 
+		<li id="algo-spanning-flex-items">
+			<strong>Increase sizes to accommodate spanning items crossing flexible tracks:</strong>
+			Next, repeat the previous step
+			instead considering (together, rather than grouped by span size)
+			all items
+			that <em>do</em> span a track with a <a>flexible sizing function</a>
+			while
+			<ul>
+				<li>
+					treating flexible tracks as having
+					a <a>max track sizing function</a> equal to their <a>min track sizing function</a>
+				<li>
+					distributing space <em>only</em> to flexible tracks
+					(i.e. treating all other tracks as having a <a>fixed sizing function</a>
+					of their current <a>base size</a>)
+				<li>
+					distributing space to such tracks
+					according to the ratios of their <a>flexible sizing functions</a>
+					rather than distributing space equally
+			</ul>
+
 		<li id="algo-finite-growth">
 			If any track still has an infinite <a>growth limit</a>
 			(because, for example, it had no items placed in it),
@@ -4305,6 +4327,45 @@ Major Changes</h4>
 			they must be resolved against the inline dimension, as for blocks.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/2085">Issue 2085</a>)
 
+		<li id="change-2017-span-flexible-tracks">
+			Adjusted handling of items spanning flexible tracks
+			to intrinsic track sizes so that
+			they contribute to the size of flexible tracks that have an intrinsic min
+			rather than being ignored.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/2177">Issue 2177</a>)
+			<blockquote>
+				<ul>
+					<li>
+						<strong>Size tracks to fit non-spanning items:</strong>
+						For each track with an intrinsic <a>track sizing function</a>
+						<ins>and not a <a>flexible sizing function</a></ins>,
+						consider the items in it with a span of 1:
+					<li>
+						&hellip;
+					<li>
+						<ins><strong>Increase sizes to accommodate spanning items crossing flexible tracks:</strong>
+						Next, repeat the previous step
+						instead considering (together, rather than grouped by span size)
+						all items
+						that <em>do</em> span a track with a <a>flexible sizing function</a>
+						while
+						<ul>
+							<li>
+								treating flexible tracks as having
+								a <a>max track sizing function</a> equal to their <a>min track sizing function</a>
+							<li>
+								distributing space <em>only</em> to flexible tracks
+								(i.e. treating all other tracks as having a <a>fixed sizing function</a>
+								of their current <a>base size</a>)
+							<li>
+								distributing space to such tracks
+								according to the ratios of their <a>flexible sizing functions</a>
+								rather than distributing space equally
+						</ul>
+						</ins>
+				</ul>
+			</blockquote>
+
 		<li id="change-2017-repeat-serialization">
 			Require the used value of a track listing
 			to be serialized without using ''repeat()'' notation.