[css-color-4] More precise clamping of values, helps w3c#3845

Author: svgeesus

css-color-4/Overview.bs

@@ -916,7 +916,7 @@ HSL Colors: ''hsl()'' and ''hsla()'' functions</h2>
 	while ''100%'' is white and ''0%'' is black.
 	If the saturation or lightness are less than ''0%''
 	or greater than ''100%'',
-	they are clipped to those values before being converted to an RGB color.
+	they are clamped to those values before being converted to an RGB color.
 
 	The final argument specifies the alpha channel of the color.
 	It's interpreted identically to the fourth argument of the ''rgb()'' function.
@@ -1755,9 +1755,10 @@ Specifying Lab and LCH: the lab() and lch() functional notations</h3>
 	similar to the lightness argument of ''hsl()''.
 	However, CIE Lightness <em>can</em> exceed this range on some systems,
 	with extra-bright whites using a lightness up to ''400''.
-	Values less than ''0'' must be clipped to ''0''; values greater than
+	Values less than ''0'' must be clamped to ''0'' at computed-value time;
+	values greater than
 	''100'' are permitted (for forwards compatibility with High Dynamic Range (HDR),
-	and must not be clipped.
+	and must not be clamped.
 
 	The second and third arguments are the distances along the "a" and "b" axises
 	in the Lab colorspace,
@@ -1784,7 +1785,7 @@ Specifying Lab and LCH: the lab() and lch() functional notations</h3>
 	while its maximum is theoretically unbounded
 	(but in practice does not exceed ''230'').
 	If the provided value is negative,
-	it is clamped to ''0''.
+	it is clamped to ''0'' at computed-value time.
 
 	The third argument is the hue.
 	It's interpreted identically to the <<hue>> argument of ''hsl()'',
@@ -2358,7 +2359,7 @@ Device-dependent CMYK Colors: the ''device-cmyk()'' function</h2>
 	These two usages are equivalent, and map to each other linearly.
 	Values less than 0 or 0%, or greater than 1 or 100%,
 	are not invalid;
-	instead, they are clamped to 0/0% or 1/100%.
+	instead, they are clamped to 0/0% or 1/100% at computed-value time.
 
 	The fifth argument specifies the alpha channel of the color.
 	It's interpreted identically to the fourth argument of the ''rgb()'' function.