offsetAngle method

double offsetAngle([
  1. Offset center = Offset.zero
])

给定一个点的坐标和圆心坐标求，求点的偏移角度

Implementation

double offsetAngle([Offset center = Offset.zero]) {
  double d = atan2(dy - center.dy, dx - center.dx);
  if (d < 0) {
    d += 2 * pi;
  }
  return d * 180 / pi;
}