code: function(x, y){
                  if(x < 0 || y < 0)
                      return;
  
                  var me = this,
                      heatmap = me.get("heatmap"),
                      data = me.get("data");
  
                  if(!data[x])
                      data[x] = [];
  
                  if(!data[x][y])
                      data[x][y] = 0;
  
                  // if count parameter is set increment by count otherwise by 1
                  data[x][y]+=(arguments.length<3)?1:arguments[2];
                  
                  me.set("data", data);
                  // do we have a new maximum?
                  if(me.max < data[x][y]){
                      // max changed, we need to redraw all existing(lower) datapoints
                      heatmap.get("actx").clearRect(0,0,heatmap.get("width"),heatmap.get("height"));
                      me.setDataSet({ max: data[x][y], data: data }, true);
                      return;
                  }
                  heatmap.drawAlpha(x, y, data[x][y], true);
              }
docs: function for adding datapoints to the store datapoints are usually defined by x and y but could also contain a third parameter which represents the occurrence