anchor.diff:    }
   
     Size get size(){
  -    return new Size(width, height);
  +    return new Size(_width, _height);
     }
  +  
  +  num get width(){ return _width; }
  +  num get height(){ return _height; }
   
     AffineTransform getTransform() {
       var tx = new AffineTransform();
  
positive.code:   final List<AffineTransform> _transforms;
    final HashMap<Property, Object> propertyValues;
    final bool cacheEnabled;
    num width, height, _alpha;
    Size _lastDrawSize;
    bool clip = false;
    IElementParent _parent;
  
    PElement(int this.width, int this.height, [bool this.cacheEnabled = false]) :
      _transforms = new List<AffineTransform>(),
      propertyValues = new HashMap<Property, Object>()
    {
  
negative.code:   }
  
    void _invalidateParent(){
      assert(this._parent != null);
      _parent.childInvalidated(this);
    }
  }
  