import 'package:flutter/material.dart';

/// A dashed rounded-rectangle outline: the target a bar is measured against.
class DashedOutline extends CustomPainter {
  final Color color;

  final double radius;

  const DashedOutline({required this.color, this.radius = 10});

  @override
  void paint(Canvas canvas, Size size) {
    if (size.height <= 0) {
      return;
    }
    final Paint paint = Paint()
      ..color = color
      ..style = PaintingStyle.stroke
      ..strokeWidth = 1.2;

    final Path outline = Path()
      ..addRRect(
          RRect.fromRectAndRadius(Offset.zero & size, Radius.circular(radius)));

    const double dash = 4;
    const double gap = 3;
    for (final metric in outline.computeMetrics()) {
      double distance = 0;
      while (distance < metric.length) {
        canvas.drawPath(metric.extractPath(distance, distance + dash), paint);
        distance = distance + dash + gap;
      }
    }
  }

  @override
  bool shouldRepaint(DashedOutline oldDelegate) =>
      oldDelegate.color != color || oldDelegate.radius != radius;
}