add P3 to utilitties

Author: svgeesus

css-color-4/LCH-examples.html

@@ -3,29 +3,31 @@
 	<script src="math.js"></script>
     <script src="conversions.js"></script>
     <textarea id="sRGBresults"></textarea>
-    <!-- <textarea id="P3results"></textarea>
-    <textarea id="Rec2020results"></textarea> -->
+    <textarea id="P3results"></textarea>
+    <textarea id="Rec2020results"></textarea>
 	<script>
 	// convert a sampling of
     // several RGB colorspaces
     // to Lab and LCH
 
     console.log("test sRGB");
-    sRGBresults.value += 'sRGB';
-// 	for (var r =0; r <=1; r+=0.5) {
-//         for (var g =0; g <=1; g+=0.5) {
-//             for (var b =0; b <=1; b+=0.5) {
-//                 sRGBresults.value += `RGB=${r},${g},${b}
-// `;
-//                 var lab = XYZ_to_Lab(D65_to_D50(lin_sRGB_to_XYZ(lin_sRGB([r, g, b]))));
-//                 sRGBresults.value += `Lab=${lab}
-// `;
-//                 sRGBresults.value += `LCH=${Lab_to_LCH(lab)}
+    sRGBresults.value += `sRGB
 
-// `;
-//             }
-//         }
-//     };
+`;
+	for (var r =0; r <=1; r+=0.5) {
+        for (var g =0; g <=1; g+=0.5) {
+            for (var b =0; b <=1; b+=0.5) {
+                sRGBresults.value += `RGB=${r},${g},${b}
+`;
+                var lab = XYZ_to_Lab(D65_to_D50(lin_sRGB_to_XYZ(lin_sRGB([r, g, b]))));
+                sRGBresults.value += `Lab=${lab}
+`;
+                sRGBresults.value += `LCH=${Lab_to_LCH(lab)}
+
+`;
+            }
+        }
+    };
 
     console.log("image-p3");
 

css-color-4/utilities.js

@@ -35,6 +35,16 @@ function sRGB_to_LCH(RGB) {
     return Lab_to_LCH(XYZ_to_Lab(D65_to_D50(lin_sRGB_to_XYZ(lin_sRGB(RGB)))));
 }
 
+function P3_to_LCH(RGB) {
+    // convert an array of gamma-corrected display-p3 values
+    // in the 0.0 to 1.0 range
+    // to linear-light display-p3, then to CIE XYZ,
+    // then adapt from D65 to D50,
+    // then convert XYZ to CIE Lab
+    // and finally, convert to CIE LCH
+
+    return Lab_to_LCH(XYZ_to_Lab(D65_to_D50(lin_P3_to_XYZ(lin_P3(RGB)))));
+}
 function LCH_to_sRGB(LCH) {
     // convert an array of CIE LCH values
     // to CIE Lab, and then to XYZ,
@@ -47,4 +57,18 @@ function LCH_to_sRGB(LCH) {
     // so check for that :)
 
     return gam_sRGB(XYZ_to_lin_sRGB(D50_to_D65(Lab_to_XYZ(LCH_to_Lab(LCH)))));
+}
+
+function LCH_to_P3(LCH) {
+    // convert an array of CIE LCH values
+    // to CIE Lab, and then to XYZ,
+    // adapt from D50 to D65,
+    // then convert XYZ to linear-light display-p3
+    // and finally to gamma corrected display-p3
+    // for in-gamut colors, components are in the 0.0 to 1.0 range
+    // out of gamut colors may have negative components
+    // or components greater than 1.0
+    // so check for that :)
+
+    return gam_P3(XYZ_to_lin_P3(D50_to_D65(Lab_to_XYZ(LCH_to_Lab(LCH)))));
 }