getPoint method

@override Vector? getPoint(num t, [ Vector? optionalTarget ])

Implementation

@override
Vector? getPoint(num t, [Vector? optionalTarget]) {
  final point = optionalTarget ?? Vector2();

  const twoPi = math.pi * 2;
  num deltaAngle = aEndAngle - aStartAngle;
  final samePoints = deltaAngle.abs() < MathUtils.epsilon;

  // ensures that deltaAngle is 0 .. 2 PI
  while (deltaAngle < 0) {
    deltaAngle += twoPi;
  }
  while (deltaAngle > twoPi) {
    deltaAngle -= twoPi;
  }

  if (deltaAngle < MathUtils.epsilon) {
    if (samePoints) {
      deltaAngle = 0;
    } else {
      deltaAngle = twoPi;
    }
  }

  if (aClockwise == true && !samePoints) {
    if (deltaAngle == twoPi) {
      deltaAngle = -twoPi;
    } else {
      deltaAngle = deltaAngle - twoPi;
    }
  }

  final angle = aStartAngle + t * deltaAngle;
  double x = aX + xRadius * math.cos(angle);
  double y = aY + yRadius * math.sin(angle);

  if (aRotation != 0) {
    final cos = math.cos(aRotation);
    final sin = math.sin(aRotation);

    final tx = x - aX;
    final ty = y - aY;

    // Rotate the point about the center of the ellipse.
    x = tx * cos - ty * sin + aX;
    y = tx * sin + ty * cos + aY;
  }

  return point.setValues(x, y);
}