From 06c0e1ee108f0fa627b6b2c39f70cf64869ce91d Mon Sep 17 00:00:00 2001
From: Shawn <sorourke@elliottbayenergy.com>
Date: Mon, 25 Nov 2013 13:59:47 -0800
Subject: [PATCH 1/1] Speed up renerding of stacked graph by avoiding the loop
 in updateNextPoint(), when stackedGraphNaNFill = 'none'.

---
 dygraph.js | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/dygraph.js b/dygraph.js
index a96b98f..85885e2 100644
--- a/dygraph.js
+++ b/dygraph.js
@@ -2366,19 +2366,24 @@ Dygraph.stackPoints_ = function(
 
     var actualYval = point.yval;
     if (isNaN(actualYval) || actualYval === null) {
-      // Interpolate/extend for stacking purposes if possible.
-      updateNextPoint(i);
-      if (prevPoint && nextPoint && fillMethod != 'none') {
-        // Use linear interpolation between prevPoint and nextPoint.
-        actualYval = prevPoint.yval + (nextPoint.yval - prevPoint.yval) *
-            ((xval - prevPoint.xval) / (nextPoint.xval - prevPoint.xval));
-      } else if (prevPoint && fillMethod == 'all') {
-        actualYval = prevPoint.yval;
-      } else if (nextPoint && fillMethod == 'all') {
-        actualYval = nextPoint.yval;
-      } else {
+      if(fillMethod == 'none') {
         actualYval = 0;
       }
+      else {
+        // Interpolate/extend for stacking purposes if possible.
+        updateNextPoint(i);
+        if (prevPoint && nextPoint && fillMethod != 'none') {
+          // Use linear interpolation between prevPoint and nextPoint.
+          actualYval = prevPoint.yval + (nextPoint.yval - prevPoint.yval) *
+              ((xval - prevPoint.xval) / (nextPoint.xval - prevPoint.xval));
+        } else if (prevPoint && fillMethod == 'all') {
+          actualYval = prevPoint.yval;
+        } else if (nextPoint && fillMethod == 'all') {
+          actualYval = nextPoint.yval;
+        } else {
+          actualYval = 0;
+        }
+      }
     } else {
       prevPoint = point;
     }
-- 
2.7.4