isPointAlongCircle function
Implementation
bool isPointAlongCircle(Offset point, Offset center, double radius) {
/// distance is root(sqr(x2 - x1) + sqr(y2 - y1))
/// i.e., (7,8) and (3,2) -> 7.21
var d1 = pow(point.dx - center.dx, 2);
var d2 = pow(point.dy - center.dy, 2);
var distance = sqrt(d1 + d2);
return (distance - radius).abs() < 10;
}