1 
  2 /**
  3  * A stacked graph that is centered around the x-axis
  4  * 
  5  * @class
  6  * @param target
  7  * @augments StackedGraph
  8  * @returns
  9  */
 10 function ThemeRiver(target){
 11 	StackedGraph.call(this, target);
 12 }
 13 
 14 ThemeRiver.prototype = new StackedGraph();
 15 
 16 /**
 17  * Centering is done by offsetting the baseline by the half of the sum.
 18  */
 19 ThemeRiver.prototype.baselineAt = function(x){
 20 	return -0.5*this.sumAt(x);
 21 //	return -0.5*this._timeSeriesSums[x];
 22 };
 23