anchor.diff:    
     num get x => valueX ;
     num get y => valueY ;
  +  
  +  operator == (XChartsData o) {
  +    return super==(o)
  +        && this.valueY == o.valueY
  +        && this.valueX == o.valueX ;
  +  }
   
     Point get point => new Point(x,y) ;
     Point get centerPoint => new Point(x + (width != null ? width/2 : 0) , y + (height != null ? height/2 : 0) ) ;
  
positive.code:   
    XChartsDataSeries( this.name , this.data , [ this.color , this.enabled = true ]) {
      sortData() ;  
    }
    
    void sortData() {
  
negative.code:   String get labelX => _labelX != null ? _labelX : valueX.toString() ;
    String get labelY => _labelY != null ? _labelY : valueY.toString() ;
    
    void set labelY(String label) {
        this._labelY = label;           
    }
    
    void set labelX(String label) {
        this._labelX = label;           
    }
     
  
  //   set labelY => _labelY != null ? _labelY : valueY.toString() ;
    
    XChartsData( this.valueX , this.valueY , [this._labelX , this._labelY , this.hint]) ;
    
    XChartsData clone() {
  