Rotation of a `Shape` relative to its `Layout`

Thanks for all the time you've been putting into this crate recently.

I would like to plot a confidence interval on a ScatterPolar plot, using an ellipse:

This looks very similar to this example from the book, but it also requires the abilty to rotate the ellipse relative to the layout.

Is it possible to rotate a shape? Am I missing a more obvious solution?

从 issue 中链接的 ScatterPolar 示例所使用的 Shape 和 Layout 行为入手，并将其与所请求的置信区间椭圆进行比较。确定应如何表示和记录相对于 layout 的旋转。完成意味着 Shape 可以针对这一用例进行旋转，并且该行为在更新后的示例或测试中得到演示。