paint method

@override void paint(Canvas cv, Size size, double p, Offset center, Color color, { double radiusMultiplier = 1, Offset positionOffset = Offset.zero, })

Implementation

@override
void paint(Canvas cv, Size size, double p, Offset center, Color color,
    {double radiusMultiplier = 1, Offset positionOffset = Offset.zero}) {
  final c = center + positionOffset;
  final rnd = math.Random(42);
  final minSide = math.min(size.width, size.height);

  final spawnRadius = minSide * spawnScale * radiusMultiplier;

  // sudut tetap
  final angles = List<double>.generate(
    particleCount,
    (i) => useUniformAngle
        ? (i / particleCount) * 2 * math.pi
        : rnd.nextDouble() * 2 * math.pi,
  );

  for (var i = 0; i < particleCount; i++) {
    final delay = i * 0.02;
    final rawT = p - delay;
    if (rawT <= 0) continue;

    final t = (rawT / (1 - delay)).clamp(0.0, 1.0);
    final angle = angles[i];

    // ── posisi radial ──
    double dist;
    if (t < _spawnEnd) {
      final tt = t / _spawnEnd; // 0‑1
      dist = spawnRadius * (1 - _easeOutQuad(tt));
    } else if (t < _convergeEnd) {
      final tt = (t - _spawnEnd) / (_convergeEnd - _spawnEnd);
      dist = spawnRadius * (1 - _easeInBack(tt));
    } else {
      final tt = (t - _convergeEnd) / (1 - _convergeEnd);
      dist = spawnRadius * (0.15 * (1 - tt)); // makin dekat ke 0
    }

    final pos = c + Offset(math.cos(angle), math.sin(angle)) * dist;

    // ── skala & opasitas ──
    final scale = t < _spawnEnd
        ? t / _spawnEnd
        : t > _convergeEnd
            ? (1 - t) / (1 - _convergeEnd)
            : 1.0;

    final opacity = scale; // sama‑sama turun/naik

    // ── warna ──
    Color col = color;
    if (enableHueTilt) {
      final hsl = HSLColor.fromColor(color);
      final shift = (angle / (2 * math.pi)) * 360 * hueTiltRange;
      col = hsl
          .withHue((hsl.hue + shift) % 360)
          .withSaturation((hsl.saturation * saturationBoost).clamp(0, 1))
          .toColor();
    }
    col = col.withOpacity(opacity.toDouble());

    // ── gambar ──
    final rad = circleRadius * radiusMultiplier * scale;
    cv.drawCircle(pos, rad, Paint()..color = col);

    final tailLen = rad * tailFactor;
    final tailEnd = pos + Offset(math.cos(angle), math.sin(angle)) * tailLen;
    cv.drawLine(
        pos,
        tailEnd,
        Paint()
          ..color = col
          ..strokeWidth = rad * .8
          ..strokeCap = StrokeCap.round);
  }
}