half_circle_progress_bar_painter_paint_v2.dart

@override
void paint(Canvas canvas, Size size) {
  final center = size.bottomCenter(Offset(0, -dotRadius));

  var radius = startBarRadius;

  for (var layer = 0; layer < layers; layer++) {
    final lengthOfHalfCircle = pi * radius;

    final dotsNumber = (lengthOfHalfCircle / _dotsSizeWithSpacing).floor();

    final angleStep = _halfCircle / (dotsNumber - 1);
    var angle = _startAngle;

    final progressItems = (dotsNumber * progress).toInt();

    for (var dot = 0; dot < dotsNumber; dot++) {
      final radian = pi * 2 * angle / _circle;

      canvas.drawCircle(
        Offset(
          radius * sin(radian) + center.dx,
          radius * cos(radian) + center.dy,
        ),
        dotRadius,
        dot < progressItems ? _progressPaint : _paint,
      );

      angle -= angleStep;
    }

    radius += _dotDiameter + layersSpacing;
  }
}