anchor.diff:    void set scale(double scale) {
       assert(scale != null);
       _scaleX = _scaleY = scale;
  -    _invalidateTransformMatrix();
  +    invalidateTransformMatrix();
     }
   
     /// The horizontal scale of this node relative its parent.
  
positive.code:   void set rotation(double rotation) {
      assert(rotation != null);
      _rotation = rotation;
      _invalidateTransformMatrix();
    }
  
    /// The position of this node relative to its parent.
  
negative.code:   ///
    ///     Matrix4 matrix = myNode.transformMatrix;
    Matrix4 get transformMatrix {
      if (_transformMatrix == null) {
        _transformMatrix = computeTransformMatrix();
      }
      return _transformMatrix;
    }
  
    Matrix4 computeTransformMatrix() {
      double cx, sx, cy, sy;
  
      if (_rotation == 0.0) {
  