Dynamically Resizing Selection Box

So basically, I am working on building the in-game menu for my RPG, but I am having a time figuring out how to show which menu elements are selected. Basically, my script keeps track of which objects are selectable and moves a prefab around that has a selection box outline image component. I'd like to have the prefab dynamically resize to match the current object selected. All of this is happening on my menu canvas object. My intuition tells me I have to manipulate the rect transform width/height, but then again I'm really not sure where to begin to find the right values to generate. Any ideas or suggestions are most welcome!!! I have done a lot of searching for any similar problems but I've come up dry, so my apologies if this is old hash.

Happy coding!

 

If you make the selection box a child of the selected object, and set its anchors to stretch, then it will change its size and aspect ratio automatically based on the parent.

 

Thanks Antistone, this is the perfect solution! One thing I noticed though, if the new parent has scale values other than 1, the scale of the selection prefab seems to be automatically affected (and I'm interested in why if anyone knows...). Anyway, it is simply fixed by resetting the prefab scale attributes to 1 though.