thumb_shape.dart

import 'package:flutter/material.dart';

class CircleThumbShape extends SliderComponentShape {

  final double thumbRadius;

  const CircleThumbShape({
    this.thumbRadius = 6.0,
  });
  
  @override
  Size getPreferredSize(bool isEnabled, bool isDiscrete) {
    return Size.fromRadius(thumbRadius);
  }

  @override
  void paint(PaintingContext context, Offset center, {Animation<double> activationAnimation, Animation<double> enableAnimation, bool isDiscrete, TextPainter labelPainter, RenderBox parentBox, SliderThemeData sliderTheme, TextDirection textDirection, double value}) {
    // We need to draw the thumb here
  }

}