[css-color] @Profile, rgb to xyz utility code

Author: svgeesus

css-color/Overview.bs

@@ -1772,10 +1772,17 @@ are the same for colors inside the source and destination gamuts.
 <h3 id="at-profile">Specifying a color profile: the ''profile'' at-rule</h3>
 <!-- we agreed to call it profile rather than color-profile or icc-profile, for brevity -->
 
-In a very similar way to the ''<@font-face.'' at-rule, the ''<@profile>'' at-rule has a descriptor 
+The <dfn data-dfn-type='at-rule' id="at-ruledef-profile">@profile</dfn> 
+rule is a  group rule.  It consists of the at-keyword
+'@profile' followed by an identifier, followed by a group rule body.
+
+In a very similar way to the ''<@font-face.'' at-rule, the ''<@profile>'' 
+at-rule has a descriptor 
 to give the profile a name which will be used inside the stylesheet, 
 <!-- is this actualy a descriptor, or a parameter to the at-rule?-->
-and another descriptor to point to the actual data ('src', just like 'src'' in font-face.) 
+and another descriptor to point to the actual 
+data (<dfn for="@profile/src">src</dfn>, just like 
+<dfn for="@font-face/src">src</dfn> in font-face.) 
 <!-- not clear how I link to the two different descriptors therte, in bikeshed syntax -->
 
 <!-- should we add a format field to this descriptor, like with font-face src? it is always ICC format
@@ -1786,7 +1793,7 @@ In adition there is a third, optional descriptor to define the ''rendering inten
 This is only needed if the profile linked to has data for multiple rendering intents.
 
 <pre class="prod">
-	<dfn at-rule 
+	<dfn at-rule>FIXME</dfn>
 </pre>
 
 <h2 id='cmyk-colors'>

css-color/matrixmaker.html

@@ -24,6 +24,20 @@
 		const xwhite=0.3127 ;
 		const ywhite=0.3290 ;
 
+		// Relative XYZ values. Copy-paste-o-rama
+		var XWhite=xwhite/ywhite;
+		var YWhite=1;
+		var ZWhite=(1 - xwhite - ywhite)/ywhite;
+		
+		var XRed=xred/yred;
+		var YRed=1;
+		var ZRed=(1 - xred - yred)/yred;
+		
+		var XGreen=xgreen/ygreen;
+		var YGreen=1;
+		var ZGreen=(1 - xgreen - ygreen)/green;
+		
+		var white = math.matrix([])
 
 	</script>
 </html>