Circular UIView, efficient when resizing

CircleView.swift

//
//  CircleView.swift
//
//  Created by Ashton Meuser on 2017-11-08.
//  Copyright © 2017 Ashton Meuser. All rights reserved.
//

import UIKit

class CircleView: UIView {
    var fillColor: UIColor = UIColor.clear
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
    
    func setup() {
        isOpaque = false
        backgroundColor = UIColor.clear
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        setNeedsDisplay()
    }
    
    override func draw(_ rect: CGRect) {
        let path = UIBezierPath(ovalIn: rect)
        fillColor.setFill()
        path.fill()
    }
}