drawShadow method
Implementation
void drawShadow(Canvas canvas, Size size) async{
canvas.drawPath(
Path()
..addRect(
Rect.fromPoints(Offset(-15, -15), Offset(size.width+15, size.height+15)))
..addOval(
Rect.fromPoints(Offset(0, 0), Offset(size.width, size.height)))
..fillType = PathFillType.evenOdd,
Paint()
..color= NUIColors.NUIBlack.withOpacity(0.3)
..maskFilter = MaskFilter.blur(BlurStyle.normal, convertRadiusToSigma(3))
);
}