如何在Flutter中设置圆形图表边缘的样式

import 'package:flutter/material.dart';
import 'dart:math';

class CircularChart extends StatelessWidget {
  final double radius;
  final double strokeWidth;
  final Color strokeColor;
  final Color fillColor;
  final double percentage;

  CircularChart({
    required this.radius,
    required this.strokeWidth,
    required this.strokeColor,
    required this.fillColor,
    required this.percentage,
  });

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: _CircularChartPainter(
        radius: radius,
        strokeWidth: strokeWidth,
        strokeColor: strokeColor,
        fillColor: fillColor,
        percentage: percentage,
      ),
    );
  }
}

class _CircularChartPainter extends CustomPainter {
  final double radius;
  final double strokeWidth;
  final Color strokeColor;
  final Color fillColor;
  final double percentage;

  _CircularChartPainter({
    required this.radius,
    required this.strokeWidth,
    required this.strokeColor,
    required this.fillColor,
    required this.percentage,
  });

  @override
  void paint(Canvas canvas, Size size) {
    final center = Offset(size.width / 2, size.height / 2);
    final startAngle = -pi / 2;
    final sweepAngle = 2 * pi * percentage;

    final paint = Paint()
      ..style = PaintingStyle.stroke
      ..strokeWidth = strokeWidth
      ..color = strokeColor;

    canvas.drawCircle(center, radius, paint);

    final fillPaint = Paint()
      ..style = PaintingStyle.fill
      ..color = fillColor;

    canvas.drawArc(
      Rect.fromCircle(center: center, radius: radius),
      startAngle,
      sweepAngle,
      true,
      fillPaint,
    );
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) {
    return true;
  }
}

void main() {
  runApp(MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: Text('Circular Chart'),
      ),
      body: Center(
        child: CircularChart(
          radius: 100,
          strokeWidth: 10,
          strokeColor: Colors.grey,
          fillColor: Colors.blue,
          percentage: 0.75,
        ),
      ),
    ),
  ));
}