X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph.js;h=4404a976ce4d1d0231f34a33623e3fb3d081f7bf;hb=bcc657d89e20b0c3cd80c768fe09301dc9a49273;hp=83d4e8c33e3de5944e15fe27f741f8e0c47e2a49;hpb=25f76ae32a735757d6c5570e966a9d3774f64117;p=dygraphs.git

diff --git a/dygraph.js b/dygraph.js
index 83d4e8c..4404a97 100644
--- a/dygraph.js
+++ b/dygraph.js
@@ -866,13 +866,13 @@ Dygraph.prototype.createDragInterface_ = function() {
     isZooming: false,
     isPanning: false,  // is this drag part of a pan?
     is2DPan: false,    // if so, is that pan 1- or 2-dimensional?
-    dragStartX: null,
-    dragStartY: null,
-    dragEndX: null,
-    dragEndY: null,
+    dragStartX: null, // pixel coordinates
+    dragStartY: null, // pixel coordinates
+    dragEndX: null, // pixel coordinates
+    dragEndY: null, // pixel coordinates
     dragDirection: null,
-    prevEndX: null,
-    prevEndY: null,
+    prevEndX: null, // pixel coordinates
+    prevEndY: null, // pixel coordinates
     prevDragDirection: null,
 
     // The value on the left side of the graph when a pan operation starts.
@@ -887,7 +887,8 @@ Dygraph.prototype.createDragInterface_ = function() {
     // panning operation.
     dateRange: null,
 
-    // Utility function to convert page-wide coordinates to canvas coords
+    // Top-left corner of the canvas, in DOM coords
+    // TODO(konigsberg): Rename topLeftCanvasX, topLeftCanvasY.
     px: 0,
     py: 0,
 
@@ -2409,9 +2410,13 @@ Dygraph.prototype.rollingAverage = function(originalData, rollPeriod) {
           count -= 1;
         }
       }
-      rollingData[i] = [originalData[i][0], [ 1.0 * mid / count,
-                                              1.0 * (mid - low) / count,
-                                              1.0 * (high - mid) / count ]];
+      if (count) {
+        rollingData[i] = [originalData[i][0], [ 1.0 * mid / count,
+                                                1.0 * (mid - low) / count,
+                                                1.0 * (high - mid) / count ]];
+      } else {
+        rollingData[i] = [originalData[i][0], [null, null, null]];
+      }
     }
   } else {
     // Calculate the rolling average for the first rollPeriod - 1 points where