getPolygonVertices

The vertices of a regular sides-gon scaled to exactly fill a width × height box, starting at the apex (the -π/2 angle) and running clockwise.

This is the generator behind the triangle, diamond, pentagon, hexagon and octagon outlines, exported so that anything drawing a preview of one of those — a placement ghost, a custom geo type — calls it instead of restating the trigonometry. The result always fills the box exactly, so its bounds are the box.