Animation is slow in flutter - flutter

Question

I am animating line in canvas in flutter.i am using AnimationController to control the animation. When i animate a single line, it is get animated without any lag or performance issue.But when i animate more than 10 lines it gets struck and lagging when rendering the line.In each frame redraw is getting called in order to animate the line .How to overcome this issue.
Code Snippet
class CrossPainter extends CustomPainter {
Paint _paint;
double _fraction;
CrossPainter(this._fraction) {
_paint = Paint()
..color = Colors.blue
..strokeWidth = 10.0
..strokeCap = StrokeCap.round;
}
#override
void paint(Canvas canvas, Size size) {
canvas.clipRect(Rect.fromLTRB(0, 0, _fraction * size.width , size.height));
canvas.drawLine(Offset(0.0, 0.0), Offset(size.width , size.height ), _paint);
canvas.drawLine(Offset(size.width, 0.0), Offset(size.width - size.width, size.height ), _paint);
}
#override
bool shouldRepaint(CrossPainter oldDelegate) {
return oldDelegate._fraction != _fraction;
}
}
typedef FadeBuilder = Widget Function(BuildContext, double);
class _AnimationWrapper extends StatefulWidget {
const _AnimationWrapper({this.builder});
final FadeBuilder builder;
#override
_AnimationWrapperState createState() => _AnimationWrapperState();
}
class _AnimationWrapperState extends State<_AnimationWrapper> with SingleTickerProviderStateMixin {
double opacity = 0.0;
double _fraction = 0.0;
Animation<double> animation;
AnimationController controller;
#override
void initState() {
super.initState();
controller = AnimationController(duration: Duration(milliseconds: 3000), vsync: this);
animation = Tween(begin: 0.0, end: 1.0).animate(controller)
..addListener(() {
setState(() {
_fraction = animation.value;
});
}
);
controller.forward();
}
#override void didUpdateWidget(_AnimationWrapper oldWidget) {
// TODO: implement didUpdateWidget
super.didUpdateWidget(oldWidget);
}
#override
Widget build(BuildContext context) {
return CustomPaint(painter: CrossPainter(_fraction));
}
}
Thanks
Ashwin

Answer 1

If I understand your problem correct - these lags caused by debug mode. There are always small problems with animation in debug.
Try to build release apk and launch it