code: function Matrix2D(a, b, c, d, e, f) {
      _classCallCheck(this, Matrix2D);
  
      this.a = a !== undefined ? a : 1;
      this.b = b !== undefined ? b : 0;
      this.c = c !== undefined ? c : 0;
      this.d = d !== undefined ? d : 1;
      this.e = e !== undefined ? e : 0;
      this.f = f !== undefined ? f : 0;
    }
docs: Matrix2D
  
  [a c e]
  [b d f]
  [0 0 1]
  
  @param {number} a
  @param {number} b
  @param {number} c
  @param {number} d
  @param {number} e
  @param {number} f
  @returns {module:kld-affine.Matrix2D}