[css-anchor-position] Drawing irregular shapes between two items

[JacobDB]

When anchoring between two items, it would be very useful to be able to draw irregular shapes. For example, when drawing an invisible triangle to improve hover area, such as in the mockup below.

https://www.mayank.co/blog/hover-triangles

https://www.w3.org/TR/css-anchor-position-1/

[kizu]

This could be a good use case for #8586, where allowing us to use anchor() and anchor-size() in all properties could allow us to calculate the polygon() necessary for the clip-path().

With some hacks, I'm pretty sure the hover triangles could be possible with what we have already in anchor positioning, but having an easier way of doing it could be very useful.