off screen widget stay on screen

Hello i am looking to do like in this video, with blueprint :
Off screen Indicator test build UE4 - YouTube ,
when the widget is outside the screen, it stays on the border instead of disapearing.
I can find easyly the screen position of my widget ( project world to screen of that actor ), but to move it I try to use set render translation of the widget, but it is in local screen space ( and so always 0,0 ), can’t just clamp the values to lock it onscreen …
Wonder if anyone got an idea, thanks !