anchor.diff:        for (int j = 0 ; j < data.length ; j++) {
           var d = data[j] ;
           
  -        var vX = d.valueY ;
  -        var vY = d.valueX ;
  -        
  -        double valXRatio = (vX-yValsMin) / yValsRange ;
  -        double valYRatio = (vY-xValMin) / xValRange ;
  -        
  -        num valX = axisXinit.x + axixXwidth * valYRatio ;
  -        num valY = axisYend.y + axixYheight * (1-valXRatio) ;
  +        var vX = d.valueX ;
  +        var vY = d.valueY ;
  +        
  +        double valXRatio = (vX-xValMin) / xValRange ;
  +        double valYRatio = (vY-yValsMin) / yValsRange ;
  +        
  +        num valX = axisXinit.x + axixXwidth * valXRatio ;
  +        num valY = axisYend.y + axixYheight * (1-valYRatio) ;
           
           points.add( new Point(valX,valY) ) ;
           
  
positive.code:     
      super.drawChart(chart, context) ;
      
      List<List<Point>> seriesPoints = ret[0] ;
      List<String> seriesColors = ret[1] ;
      num xAxisX = ret[2] ;
  
negative.code:     
      List<num> yVals = chart.getYValues() ;
      
      if (yVals.isEmpty) return null ;
      
      num yValsMin = yVals.first ;
      num yValsMax = yVals.last ;
      
  