[css-values-4] Specify the 'none' argument for clamp(). w3c#9713

Author: tabatkins

css-values-4/Overview.bs

@@ -3145,6 +3145,14 @@ Comparison Functions: ''min()'', ''max()'', and ''clamp()''</h3>
 	(That is, given ''clamp(MIN, VAL, MAX)'',
 	it represents exactly the same value as ''max(MIN, min(VAL, MAX))'').
 
+	Either the min or max calculations
+	(or even both)
+	can instead be the keyword <dfn value for=clamp()>none</dfn>,
+	which indicates the value is <em>not</em> clamped from that side.
+	(That is, ''clamp(MIN, VAL, none)'' is equivalent to ''max(MIN, VAL)'',
+	''clamp(none, VAL, MAX)'' is equivalent to ''min(VAL, MAX)'',
+	and ''clamp(none, VAL, none)'' is equivalent to just ''calc(VAL)''.)
+
 	For all three functions,
 	the argument [=calculations=] can resolve to any <<number>>, <<dimension>>, or <<percentage>>,
 	but must have a [=consistent type=]
@@ -3187,8 +3195,19 @@ Comparison Functions: ''min()'', ''max()'', and ''clamp()''</h3>
 			font-size: clamp(12px, 10 * (1vw + 1vh) / 2, 100px);
 		}
 		</pre>
+
+		Or, if you only wanted to impose a minimum size,
+		but allow the font-size to grow as large as it wants:
+
+		<pre class=lang-css>
+		.type {
+			/* Force the font-size to be at least 12px */
+			font-size: clamp(12px, 10 * (1vw + 1vh) / 2, none);
+		}
+		</pre>
 	</div>
 
+
 	<div class=note>
 		Note that ''clamp()'',
 		matching CSS conventions elsewhere,
@@ -4193,7 +4212,7 @@ Syntax</h3>
 	<<calc()>>  = calc( <<calc-sum>> )
 	<<min()>>   = min( <<calc-sum>># )
 	<<max()>>   = max( <<calc-sum>># )
-	<<clamp()>> = clamp( <<calc-sum>>#{3} )
+	<<clamp()>> = clamp( [ <<calc-sum>> | none ], <<calc-sum>>, [ <<calc-sum>> | none ] )
 	<<round()>> = round( <<rounding-strategy>>?, <<calc-sum>>, <<calc-sum>> )
 	<<mod()>>   = mod( <<calc-sum>>, <<calc-sum>> )
 	<<rem()>>   = rem( <<calc-sum>>, <<calc-sum>> )
@@ -5495,7 +5514,13 @@ Recent Changes</h3>
 
 	(This is a subset of [[#additions-L3]].)
 
+	Substantial changes since <a href="https://www.w3.org/TR/2023/WD-css-values-4-20231218/">18 December 2023 WD</a>:
+
+	* Added the ''clamp()/none'' values to ''clamp()'',
+		(<a href="https://github.com/w3c/csswg-drafts/issues/9713">Issue 9713</a>)
+
 	Substantial changes since <a href="https://www.w3.org/TR/2023/WD-css-values-4-20231027/">27 October 2023 WD</a>:
+
 	* Pinned the [=default viewport-percentage units=] to the [=large viewport-percentage units=]--
 		despite violation of the “avoid dataloss by default principle”--
 		given existing interoperability and presumed Web-compat restriction.