Fix for issue #2536 (#2803)

* Fix for issue #2536

* Adjusted documentation for fix.

* Adjustments due to review

* Grrrrr whitespace

* Fixed Travis issue

docs/graph3d/index.html

@@ -532,8 +532,8 @@ var options = {
       <td>xBarWidth</td>
       <td>number</td>
       <td>none</td>
-      <td>The width of bars in x direction. By default, the width is equal to the distance
-        between the data points, such that bars adjoin each other.
+      <td>The width of bars in x direction. By default, the width is equal to the smallest distance
+        between the data points.
         Only applicable for styles <code>'bar'</code> and <code>'bar-color'</code>.</td>
     </tr>
 
@@ -575,8 +575,8 @@ var options = {
       <td>yBarWidth</td>
       <td>number</td>
       <td>none</td>
-      <td>The width of bars in y direction. By default, the width is equal to the distance
-        between the data points, such that bars adjoin each other.
+      <td>The width of bars in y direction. By default, the width is equal to the smallest distance
+        between the data points.
         Only applicable for styles <code>'bar'</code> and <code>'bar-color'</code>.</td>
     </tr>
 

lib/graph3d/Graph3d.js

@@ -327,7 +327,34 @@ Graph3d.prototype.getDistinctValues = function(data, column) {
       distinctValues.push(data[i][column]);
     }
   }
-  return distinctValues;
+  return distinctValues.sort(function(a,b) { return a - b; });
+}
+
+
+/**
+ * Determine the smallest difference between the values for given
+ * column in the passed data set.
+ *
+ * @returns {Number|null} Smallest difference value or
+ *                        null, if it can't be determined.
+ */
+Graph3d.prototype.getSmallestDifference = function(data, column) {
+  var values = this.getDistinctValues(data, column);
+  var diffs  = [];
+
+  // Get all the distinct diffs
+  // Array values is assumed to be sorted here
+  var smallest_diff = null;
+
+  for (var i = 1; i < values.length; i++) {
+    var diff = values[i] - values[i - 1];
+
+    if (smallest_diff == null || smallest_diff > diff ) {
+      smallest_diff = diff;
+    }
+  }
+
+  return smallest_diff;
 }
 
 
@@ -467,16 +494,14 @@ Graph3d.prototype._dataInitialize = function (rawData, style) {
       this.xBarWidth = this.defaultXBarWidth;
     }
     else {
-      var dataX = this.getDistinctValues(data,this.colX);
-      this.xBarWidth = (dataX[1] - dataX[0]) || 1;
+      this.xBarWidth = this.getSmallestDifference(data, this.colX) || 1;
     }
 
     if (this.defaultYBarWidth !== undefined) {
       this.yBarWidth = this.defaultYBarWidth;
     }
     else {
-      var dataY = this.getDistinctValues(data,this.colY);
-      this.yBarWidth = (dataY[1] - dataY[0]) || 1;
+      this.yBarWidth = this.getSmallestDifference(data, this.colY) || 1;
     }
   }
 
@@ -2449,4 +2474,4 @@ Graph3d.prototype.setSize = function(width, height) {
 // -----------------------------------------------------------------------------
 
 
-module.exports = Graph3d;
+module.exports = Graph3d;