DreamZap I'll be totally honest with you: I'd fear serious brain damage if I attempted that. 🤪
Setting up the vertices for a scale9 / tile grid was extremely complicated, because Starling's textures are much more than what it seems at first glance. You can have a texture frame, i.e. extend the texture with transparency on all sides; and the texture may be a SubTexture, displaying only part of a bigger texture (which might be a SubTexture itself) – and that part might be rotated! Those grids must take all of that into account.
So I'm afraid I'd rather not touch that code ever again. 😬
(Look here and you'll see what I mean. 😉)