Scaling header(appBar) with scroll interactions
Scale your header according to scroll position.
overlapContent onto center of
flexibleSpace's bottom. Its width will expand and border radius will decrease
flexibleSpace is shrinking to standard
AppBar which opacity
will change from 0 to 1.
Okey If I confuse you enough,
Look at the GIF, it explains it better =)
Inspired by ScalingLayout