Set this for drawCallback

diff --git a/dygraph.js b/dygraph.js
index ea04d3e..eab46a2 100644 (file)
--- a/dygraph.js
+++ b/dygraph.js
@@ -2726,7 +2726,7 @@ Dygraph.prototype.renderGraph_ = function(is_initial_draw) {
   this.canvas_.getContext('2d').clearRect(0, 0, this.width_, this.height_);
 
   if (this.getFunctionOption("drawCallback") !== null) {
-    this.getFunctionOption("drawCallback")(this, is_initial_draw);
+    this.getFunctionOption("drawCallback").call(this, this, is_initial_draw);
   }
   if (is_initial_draw) {
     this.readyFired_ = true;