drilldown.js in highcharts-rails-4.1.4

- old
+ new
@@ -29,27 +29,35 @@
 		ddSeriesId = 1;
 
 	// Utilities
 	/*
 	 * Return an intermediate color between two colors, according to pos where 0
-	 * is the from color and 1 is the to color
+	 * is the from color and 1 is the to color. This method is copied from ColorAxis.js
+	 * and should always be kept updated, until we get AMD support.
 	 */
 	function tweenColors(from, to, pos) {
 		// Check for has alpha, because rgba colors perform worse due to lack of
 		// support in WebKit.
-		var hasAlpha;
+		var hasAlpha,
+			ret;
 
-		from = from.rgba;
-		to = to.rgba;
-		hasAlpha = (to[3] !== 1 || from[3] !== 1);
-		if (!to.length || !from.length) {
+		// Unsupported color, return to-color (#3920)
+		if (!to.rgba.length || !from.rgba.length) {
 			Highcharts.error(23);
+			ret = to.raw;
+
+		// Interpolate
+		} else {
+			from = from.rgba;
+			to = to.rgba;
+			hasAlpha = (to[3] !== 1 || from[3] !== 1);
+			ret = (hasAlpha ? 'rgba(' : 'rgb(') + 
+				Math.round(to[0] + (from[0] - to[0]) * (1 - pos)) + ',' + 
+				Math.round(to[1] + (from[1] - to[1]) * (1 - pos)) + ',' + 
+				Math.round(to[2] + (from[2] - to[2]) * (1 - pos)) + 
+				(hasAlpha ? (',' + (to[3] + (from[3] - to[3]) * (1 - pos))) : '') + ')';
 		}
-		return (hasAlpha ? 'rgba(' : 'rgb(') + 
-			Math.round(to[0] + (from[0] - to[0]) * (1 - pos)) + ',' + 
-			Math.round(to[1] + (from[1] - to[1]) * (1 - pos)) + ',' + 
-			Math.round(to[2] + (from[2] - to[2]) * (1 - pos)) + 
-			(hasAlpha ? (',' + (to[3] + (from[3] - to[3]) * (1 - pos))) : '') + ')';
+		return ret;
 	}
 	/**
 	 * Handle animation of the color attributes directly
 	 */
 	each(['fill', 'stroke'], function (prop) {