Flutter How can I make this animation "smoother" - flutter

Question

How can I make this animation "smoother" (currently is restarts harshly on the 5 second refresh). I'd like for it to reverse maybe from the last angle?
I call this widget as this:
SpinnerAnimation(body: Icon(FontAwesomeIcons.earthAmericas, size: 33, color: Colors.white,),),
import 'dart:async';
import 'dart:math' as math;
import 'package:flutter/material.dart';
class SpinnerAnimation extends StatefulWidget {
late final Widget body;
SpinnerAnimation({required this.body});
#override
_SpinnerAnimationState createState() =>
_SpinnerAnimationState(body: this.body);
}
class _SpinnerAnimationState extends State<SpinnerAnimation>
with SingleTickerProviderStateMixin {
late final Widget body;
_SpinnerAnimationState({required this.body});
late AnimationController _controller;
double change_rotation_speed = 1.2;
#override
void initState() {
super.initState();
_controller = AnimationController(
duration: const Duration(seconds: 10),
vsync: this,
)..repeat();
//timer repeat every 5 seconds:
Timer.periodic(Duration(seconds: 5), (Timer t) => change_rotation_speed = randoDoubleGeneratorWithRange(1.2, 5) );
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return AnimatedBuilder(
animation: _controller,
child: body,
builder: (BuildContext context, Widget? child) {
return Transform.rotate(
angle: _controller.value * change_rotation_speed * math.pi,
child: child,
);
},
);
}
double randoDoubleGeneratorWithRange(double min, double max) {
//return a random double value:
var random = new Random();
double result = min + random.nextDouble() * (max - min);
//print(result);
return result;
}
}

Answer 1

You can use RotationTransition and with Animation
.............
late AnimationController _controller;
late Animation<double> animationRotation;
#override
void initState() {
super.initState();
_controller = AnimationController(
duration: const Duration(seconds: 5),
vsync: this,
)..repeat(revere:true); // set true for reverse animation
animationRotation =
Tween<double>(begin: 0.0, end: 1.0).animate(_controller);
}
........
#override
Widget build(BuildContext context) {
return AnimatedBuilder(
animation: _controller,
child: body,
builder: (BuildContext context, Widget? child) {
return RotationTransition(
turns: animationRotation,
child: child,
);
},
);
here demo link on Dartpad: https://dartpad.dev/?id=e316af128311c0b42d7aef2fd9e037df