Off-screen indicator

I’m trying to make a UMG widget with icon indicating the direction of actor that just went off camera view and sticks to the border of screen only. The thing is this indicator must constantly be changing it’s position on screen according to the position of the actor which can be still moving.

I’ve tried making a vector between the player pawn and the desired actor but don’t really know how to use it properly (not to mention screen resolution that could be changed by a player).

Thanks in advance.

^Reference picture​