anchor.diff:  
     double _stepWidth;
     double get stepWidth => _stepWidth;
  -  void set stepWidth(double value) {
  -    if (value == _stepWidth)
  -      return;
  -    _stepWidth = value;
  +  void set stepWidth(double newStepWidth) {
  +    if (newStepWidth == _stepWidth)
  +      return;
  +    _stepWidth = newStepWidth;
       markNeedsLayout();
     }
   
     double _stepHeight;
     double get stepHeight => _stepHeight;
  -  void set stepHeight(double value) {
  -    if (value == _stepHeight)
  -      return;
  -    _stepHeight = value;
  +  void set stepHeight(double newStepHeight) {
  +    if (newStepHeight == _stepHeight)
  +      return;
  +    _stepHeight = newStepHeight;
       markNeedsLayout();
     }
   
  
positive.code:   final BoxPainter _painter;
  
    BoxDecoration get decoration => _painter.decoration;
    void set decoration (BoxDecoration value) {
      assert(value != null);
      if (value == _painter.decoration)
        return;
      _removeBackgroundImageListenerIfNeeded();
      _painter.decoration = value;
      _addBackgroundImageListenerIfNeeded();
      markNeedsPaint();
    }
  
negative.code: 
    double _xRadius;
    double get xRadius => _xRadius;
    void set xRadius (double newXRadius) {
      assert(newXRadius != null);
      if (_xRadius == newXRadius)
        return;
      _xRadius = newXRadius;
      markNeedsPaint();
    }
  
    double _yRadius;
    double get yRadius => _yRadius;
    void set yRadius (double newYRadius) {
      assert(newYRadius != null);
      if (_yRadius == newYRadius)
        return;
      _yRadius = newYRadius;
      markNeedsPaint();
    }
  
  