Add missing file for whiteboard

www/whiteboard/colors.js

@@ -0,0 +1,52 @@
+define(function () {
+    var padZero = function (str, len) {
+        len = len || 2;
+        var zeros = new Array(len).join('0');
+        return (zeros + str).slice(-len);
+    };
+    var invertColor = function (hex) {
+        if (hex.indexOf('#') === 0) {
+            hex = hex.slice(1);
+        }
+        // convert 3-digit hex to 6-digits.
+        if (hex.length === 3) {
+            hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
+        }
+        if (hex.length !== 6) {
+            console.error(hex);
+            throw new Error('Invalid HEX color.');
+        }
+        // invert color components
+        var r = (255 - parseInt(hex.slice(0, 2), 16)).toString(16),
+            g = (255 - parseInt(hex.slice(2, 4), 16)).toString(16),
+            b = (255 - parseInt(hex.slice(4, 6), 16)).toString(16);
+        // pad each with zeros and return
+        return '#' + padZero(r) + padZero(g) + padZero(b);
+    };
+    var rgb2hex = function (rgb) {
+        if (rgb.indexOf('#') === 0) { return rgb; }
+        rgb = rgb.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);
+        var hex = function (x) {
+            return ("0" + parseInt(x).toString(16)).slice(-2);
+        };
+        return "#" + hex(rgb[1]) + hex(rgb[2]) + hex(rgb[3]);
+    };
+    var hex2rgba = function (hex, opacity) {
+        if (hex.indexOf('#') === 0) {
+            hex = hex.slice(1);
+        }
+        if (hex.length === 3) {
+            hex = hex[0] + hex[0] + hex[1] + hex[1] + hex[2] + hex[2];
+        }
+        if (!opacity) { opacity = 1; }
+        var r = parseInt(hex.slice(0,2), 16);
+        var g = parseInt(hex.slice(2,4), 16);
+        var b = parseInt(hex.slice(4,6), 16);
+        return 'rgba('+r+', '+g+', '+b+', '+opacity+')';
+    };
+    return {
+        invert: invertColor,
+        rgb2hex: rgb2hex,
+        hex2rgba: hex2rgba
+    };
+});