function isArc(curve,  circle) {
    var tolerance = Math.min(arcThreshold * error, arcTolerance * circle.radius / 100);

    return [0, 1/4, 1/2, 3/4, 1].every(function(point) {
        return Math.abs(getDistance(getCubicBezierPoint(curve, point), circle.center) - circle.radius) <= tolerance;
    });
}
Checks if a curve fits the given circe.

@param {Object} circle
@param {Array} curve
@return {Boolean}