Do not add interpolated points between points with null values.

curvedLines.js

@@ -205,11 +205,14 @@ ____________________________________________________
 				result.push(points[curX]);
 				result.push(points[curY]);
 
-				//add curve point
+				//add curve point; skip between nulls
+				if (typeof points[curX] === 'number' && typeof points[curY] === 'number'
+					&& typeof points[curX + ps] === 'number' && typeof points[curY + ps] === 'number') {
 					for (var x = (xStart += xStep); x < xEnd; x += xStep) {
 						result.push(x);
 						result.push(splines[j](x));
 					}
+				}
 				
 				j++;
 			}