fix alpha calculation for toHEX()

projects/coloration/src/lib/coloration.ts

@@ -219,7 +219,7 @@ export class Coloration {
     toHEX(): string {
         return this.calcColor ? this.value<string>(
             () => '#' + (0x1000000 + this.calcColor.intColor).toString(16).slice(1)
-                + (this.calcColor.alpha < 1 ? (0x100 + Math.round(this.calcColor.alpha * 256)).toString(16).slice(1) : '')
+                + (this.calcColor.alpha < 1 ? (0x100 + Math.round(this.calcColor.alpha * 255)).toString(16).slice(1) : '')
         ) : null;
     }
 
@@ -283,7 +283,7 @@ export class Coloration {
                 ? matchHex[5]
                 : (matchHex[3] ? matchHex[3][1] + matchHex[3][1] : undefined);
             intColor = parseInt(hexaColor, 16);
-            alpha = hexaAlpha !== undefined ? parseInt(hexaAlpha, 16) / 256 : 1;
+            alpha = hexaAlpha !== undefined ? parseInt(hexaAlpha, 16) / 255 : 1;
         }
 
         if (intColor === undefined) {