paint method

@override void paint(Canvas cv, Size size, double progress, Offset center, Color color, { double radiusMultiplier = 1.0, Offset positionOffset = Offset.zero, })

Implementation

@override
void paint(Canvas cv, Size size, double progress, Offset center, Color color,
    {double radiusMultiplier = 1.0, 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 partikel (deterministik)
  final angles = List<double>.generate(
    particleCount,
    (i) => useUniformAngle
        ? (i / particleCount) * 2 * math.pi
        : rnd.nextDouble() * 2 * math.pi,
  );

  for (int i = 0; i < particleCount; i++) {
    // delay ringan antar partikel
    final delay = i * 0.02;
    final rawT = progress - delay;
    if (rawT <= 0) continue;

    // normalisasi agar setiap partikel selesai di progress==1
    final t = (rawT / (1 - delay)).clamp(0.0, 1.0);

    final angle = angles[i];

    // ─── posisi radial ───
    double dist;
    if (t < _tailRetractEnd) {
      dist = spawnRadius; // tetap di tepi
    } else {
      final tt = (t - _tailRetractEnd) / (1 - _tailRetractEnd); // 0‑1
      dist = spawnRadius * (1 - _easeInQuad(tt)); // implosion
    }
    final pos = c + Offset(math.cos(angle), math.sin(angle)) * dist;

    // ─── tail length ───
    double tailLen;
    if (t < _tailRetractEnd) {
      final tailT = 1 - (t / _tailRetractEnd); // 1→0
      tailLen = circleRadius * tailFactor * tailT * radiusMultiplier;
    } else {
      tailLen = 0;
    }

    // ─── skala & opasitas dot ───
    final scale = t < _tailRetractEnd
        ? 1.0
        : 1 -
            ((t - _tailRetractEnd) / (1 - _tailRetractEnd)) *
                .4; // sedikit mengecil
    final opacity = t < _tailRetractEnd
        ? 1.0
        : 1 - ((t - _tailRetractEnd) / (1 - _tailRetractEnd)); // fade out

    // ─── warna ───
    Color col = color;
    if (enableHueTilt) {
      final hsl = HSLColor.fromColor(color);
      final hueShift = (angle / (2 * math.pi)) * 360 * hueTiltRange;
      col = hsl
          .withHue((hsl.hue + hueShift) % 360)
          .withSaturation((hsl.saturation * saturationBoost).clamp(0.0, 1.0))
          .toColor();
    }
    col = col.withOpacity(opacity.toDouble());

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

    // ─── gambar tail (jika masih ada) ───
    if (tailLen > 0) {
      final tailEnd =
          pos + Offset(math.cos(angle), math.sin(angle)) * tailLen;
      cv.drawLine(
          pos,
          tailEnd,
          Paint()
            ..color = col
            ..strokeWidth = rad * .8
            ..strokeCap = StrokeCap.round);
    }
  }
}