如你所见这里。

对于轮换，没有属性。但是这段代码使用shift属性来应用旋转。

For the rotation, there is no properties. But this code using the shift properties to apply the rotation.

在z1中，你有坐标（p，q）也可以计算正常，但只需将2D旋转矩阵应用于坐标，就可以使用移位属性。

In z1, you have the coordinate (p,q) compute normaly as well, but just by applying the 2D rotation matrix to your coordinate, you can use the shift properties.

注意，此代码更改了符号每个地方，为什么没有减去z1而不是z2。

And notice, this code change a the sign every where, that why there no minus in z1 instead of z2.

Rotation : [cos(theta) -sin(theta);
            sin(theta) cos(theta)];