code: public boolean isUniform(double eps) {
  		double v1 = xx * xx + yx * yx;
  		double v2 = xy * xy + yy * yy;
  		double e = (v1 + v2) * eps;
  		return Math.abs(v1 - v2) <= e && Math.abs(xx * xy + yx * yy) <= e;
  	}
docs: Returns TRUE if this transformation is a uniform transformation.
  
  The uniform transformation is a transformation, which transforms a square
  to a square.