[css-sizing-3] Fix the definitions of replaced max-content sizes. w3c#6072

Author: tabatkins

css-sizing-3/Overview.bs

@@ -868,66 +868,69 @@ Intrinsic Sizes</h3>
 	and if its containing block was <em>zero</em>-sized in that axis.
 	(In other words, the minimum size it has when sized as “shrink-to-fit”.)
 
-	The <a>max-content size</a> of a box in each axis
-	is the size it would have if it was
-	a float given an ''width/auto'' size in that axis
-	(and no <a lt="min size">minimum</a> or <a>maximum size</a> in that axis),
-	and if its containing block was <em>infinitely</em>-sized in that axis.
-	(In other words, the maximum size it has when sized as “shrink-to-fit”.)
-
-	The [=min-content size=] and [=max-content size=] are collectively referred to
-	as the [=intrinsic sizes=].
-
-	Note: Note that when the box has a [=preferred aspect ratio=],
-	size constraints in the opposite dimension will transfer through
-	and can affect the ''width/auto'' size in the considered one.
-	See <a href="https://www.w3.org/TR/CSS2/visudet.html">CSS2&sect;10</a>.
-
-	If the <a>max-content size</a> would depend
-	on the size of the containing block
-	(as it sometimes does for images with a [=natural aspect ratio=] but no [=natural dimensions|natural size=],
-	see <a href="https://www.w3.org/TR/CSS2/visudet.html#inline-replaced-width">CSS2&sect;10.3.2</a>)
-	such that it can't be calculated against an infinitely-sized containing block
-	then:
-
-	<dl>
-		<dt>For boxes with a [=preferred aspect ratio=], but no [=natural dimensions|natural size=]:
-		<dd>
-			* If the <a>available space</a> is <a>definite</a>
-				in the <a>inline axis</a>,
-				use the <a>stretch fit</a> into that size for the inline size
-				and calculate the block size using the aspect ratio.
-			* Otherwise
-				if the box has a <<length>> as its [=computed value=]
-				for 'min-width' or 'min-height',
-				use that size and calculate the other dimension using the aspect ratio;
-				if both dimensions have a <<length>> minimum,
-				choose the one that results in the larger overall size.
-
-				Note: This case was previous calculated from a 300x150 default size,
-				rather than the box's min size.
-				This is believed to be a better behavior,
-				and likely to be web compatible,
-				but please send feedback to the CSSWG if there are any problems.
-			* Otherwise
-				use an [=inline size=] matching
-				the corresponding dimension of the [=initial containing block=]
-				and calculate the other dimension using the aspect ratio.
-
-		<dt>For boxes without a [=preferred aspect ratio=]:
-		<dd>
-			* If the <a>available space</a> is <a>definite</a>
-				in the appropriate dimension,
-				use the <a>stretch fit</a> into that size in that dimension.
-			* Otherwise,
-				if the box has a <<length>> as its [=computed value|computed=]
-				[=minimum size=] ('min-width'/'min-height') in that dimension,
-				use that size.
-			* Otherwise,
-				use ''300px'' for the width
-				and/or ''150px'' for the height
-				as needed.
-	</dl>
+The <a>max-content size</a> of a box in each axis
+is the size it would have if it was
+a float given an ''width/auto'' size in that axis
+(and no <a lt="min size">minimum</a> or <a>maximum size</a> in that axis),
+and if its containing block was <em>infinitely</em>-sized in that axis.
+(In other words, the maximum size it has when sized as “shrink-to-fit”.)
+
+The [=min-content size=] and [=max-content size=] are collectively referred to
+as the [=intrinsic sizes=].
+
+Note: Note that when the box has a [=preferred aspect ratio=],
+size constraints in the opposite dimension will transfer through
+and can affect the ''width/auto'' size in the considered one.
+See <a href="https://www.w3.org/TR/CSS2/visudet.html">CSS2&sect;10</a>.
+
+This specification does not define how to determine the sizes of floats.
+Please refer to [[CSS2]].
+However, the [=max-content size=] of a [=replaced element=] with no [=natural size=]
+is defined below:
+
+<dl>
+	<dt>For [=replaced=] elements with a [=preferred aspect ratio=]:
+	<dd>
+		* If the <a>available space</a> is <a>definite</a>
+			in the <a>inline axis</a>,
+			use the <a>stretch fit</a> into that size for the inline size
+			and calculate the block size using the aspect ratio.
+			<!-- Technically undefined in CSS2, but this was recommended. -->
+
+		* Otherwise
+			if the box has a <<length>> as its [=computed value=]
+			for 'min-width' or 'min-height',
+			use that size and calculate the other dimension using the aspect ratio;
+			if both dimensions have a <<length>> minimum,
+			choose the one that results in the larger overall size.
+
+			Note: This case was previous calculated from a 300x150 default size,
+			rather than the box's min size.
+			This is believed to be a better behavior,
+			and likely to be web compatible,
+			but please send feedback to the CSSWG if there are any problems.
+			<!-- Brand new behavior not defined in CSS2 -->
+
+		* Otherwise
+			use an [=inline size=] matching
+			the corresponding dimension of the [=initial containing block=]
+			and calculate the other dimension using the aspect ratio.
+			<!-- More brand-new behavior, to prevent max-content size from going infinite. -->
+
+	<dt>For [=replaced elements=] without a [=preferred aspect ratio=]:
+	<dd>
+		* If the box has a <<length>> as its [=computed value|computed=]
+			[=minimum size=] ('min-width'/'min-height') in that dimension,
+			use that size.
+			<!-- New behavior made possible by auto initial value;
+				we think it's good, not 100% sure if Web-compatible. -->
+
+		* Otherwise,
+			use ''300px'' for the width
+			and/or ''150px'' for the height
+			as needed.
+			<!-- Required by CSS2 (due to Web-compat). -->
+</dl>
 
 	Since a block-level or inline-level replaced element
 	whose 'height' or 'width' <a>behaves as auto</a>