Android Camera2 - Draw Circle Focus Area

I'm trying to develop a custom application that uses Camera 2 API and I would like to add the feature 'tap to focus'. In other words, when I tap on the screen to focus, it shows a

Solution 1:

May be enough is draw circle of tap area, not focus area? In this case You can save X and Y pos of tap and use it as center of circle. And You can use any tutorial for drawing over camera preview, like that.