Ignore null values when calculating scale

diff --git a/src/Chart.Core.js b/src/Chart.Core.js
index 16f9d50d1cc16449e54d0bb81674846e38e0f7b2..3a21f0abd0c7f6455a2525e5f1220307781cfd02 100755 (executable)
--- a/src/Chart.Core.js
+++ b/src/Chart.Core.js
@@ -409,8 +409,13 @@
                                maxSteps = Math.floor(drawingSize/(textSize * 1.5)),
                                skipFitting = (minSteps >= maxSteps);
 
-                       var maxValue = max(valuesArray),
-                               minValue = min(valuesArray);
+                       // Filter out null values since these would min() to zero
+                       var values = [];
+                       each(valuesArray, function( v ){
+                               v == null || values.push( v );
+                       });
+                       var minValue = min(values),
+                           maxValue = max(values);
 
                        // We need some degree of separation here to calculate the scales if all the values are the same
                        // Adding/minusing 0.5 will give us a range of 1.