position property
The position of the widget pass to PageTransformer.transform
A position describes how visible the widget is.
The widget in the center of the screen' which is full visible, position is 0.0.
The widge in the left ,may be hidden, of the screen's position is less than 0.0, -1.0 when out of the screen.
The widge in the right ,may be hidden, of the screen's position is greater than 0.0, 1.0 when out of the screen
Implementation
final double position;