demo.swift

import UIKit

@IBDesignable
class CustomizedTabBar: UITabBar {

	private var shapeLayer: CALayer?

	private func addShape() {
		let shapeLayer = CAShapeLayer()
		shapeLayer.path = createPath2()
		shapeLayer.strokeColor = UIColor.lightGray.cgColor
		shapeLayer.fillColor = UIColor.white.cgColor
		shapeLayer.lineWidth = 1.0

		if let oldShapeLayer = self.shapeLayer {
			self.layer.replaceSublayer(oldShapeLayer, with: shapeLayer)
		} else {
			self.layer.insertSublayer(shapeLayer, at: 0)
		}

		self.shapeLayer = shapeLayer
	}

	override func draw(_ rect: CGRect) {
		self.addShape()
	}
	override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
        let buttonRadius: CGFloat = 35
        return abs(self.center.x - point.x) > buttonRadius || abs(point.y) > buttonRadius
	}
    
    func createPath2() -> CGPath {

        let height: CGFloat = 37.0
        let path = UIBezierPath()
        let centerWidth = self.frame.width / 2

        path.move(to: CGPoint(x: 0, y: 0)) // start top left
        path.addLine(to: CGPoint(x: (centerWidth - height * 2), y: 0)) // the beginning of the trough



        // first curve down
        path.addCurve(to: CGPoint(x: centerWidth, y: -40),
                      controlPoint1: CGPoint(x: (centerWidth - 30), y: 0), controlPoint2: CGPoint(x: centerWidth - 35, y: -37))
        // second curve up
        path.addCurve(to: CGPoint(x: (centerWidth + height * 2), y: 0),
                      controlPoint1: CGPoint(x: centerWidth + 35, y: -37), controlPoint2: CGPoint(x: (centerWidth + 30), y: 0))

       //  complete the rect
        path.addLine(to: CGPoint(x: self.frame.width, y: 0))
        path.addLine(to: CGPoint(x: self.frame.width, y: self.frame.height))
        path.addLine(to: CGPoint(x: 0, y: self.frame.height))
        path.close()

        return path.cgPath
    }
}

extension CGFloat {
	var degreesToRadians: CGFloat { return self * .pi / 180 }
	var radiansToDegrees: CGFloat { return self * 180 / .pi }
}