How to use mouse to rotate actor in game like in editor viewport

I need use mouse to control an actor’s rotation.But it doesn’t stiasfy me.Here is my snopshot. I want the smooth way like what we rotate actors in editor viewport. Any suggestion for me is appreciating.Btw, I try to find the source code which influence the EditorViewport’s actor transform,yet I didn’t find where it is.

Apparently this does it, and is free:

Or check this out from Everynone:

Ty,I download that plugin and find it helpful