You can use slop to calculate angle
deltaY = Y //(of Box Point 2 is (0,0) so Delta = Y2-Y1=Y2);
deltaX = X //(of Box);
Than angle in degrees is
Degrees = arctan(deltaY / deltaX) * 180 / PI
If atan2 is present in library use(JavaScript)
Degrees = Math.atan2(deltaY ,deltaX) * 180 / PI