visual on hue
        
        visual on color opacity
        
        pieces | auto split | check: min > dataMin; max < dataMax; 
        
        pieces | auto split | check: minOpen/maxOpen
        
        pieces | check: auto-sort
        
        continuous | check: area that greater than dataMax
        
        continuous | log axis | inverse axis | gradient on xAxis
        
        continuous | positive and negative | check: min > dataMin; max < dataMax; 
        
        category axis