Extension to set an extended hitbox on UIButtons.

UIButton+hitBox.swift

//
//  UIBotton+hitBox.swift
//
//  LICENSE: MIT
//

import UIKit

extension UIButton {

    private struct AssociatedKeys {
        static var hitBoxValue = "filibaba_hit_box"
    }

    var hitBox: UIEdgeInsets? {
        get {
            guard let value = objc_getAssociatedObject(self, &AssociatedKeys.hitBoxValue) as? NSValue else {
                return nil
            }

            let insets = value.UIEdgeInsetsValue()
            return insets
        }
        set {
            if let newValue = newValue {
                let value = NSValue(UIEdgeInsets: newValue)
                objc_setAssociatedObject(self, &AssociatedKeys.hitBoxValue, value, .OBJC_ASSOCIATION_COPY_NONATOMIC)
            } else {
                objc_setAssociatedObject(self, &AssociatedKeys.hitBoxValue, nil, .OBJC_ASSOCIATION_COPY_NONATOMIC)
            }
        }
    }

    public override func pointInside(point: CGPoint, withEvent event: UIEvent?) -> Bool {
        guard let hitBox = self.hitBox where self.enabled && !self.hidden else {
            return super.pointInside(point, withEvent: event)
        }

        let relativeFrame = self.bounds
        let hitFrame = UIEdgeInsetsInsetRect(relativeFrame, hitBox)

        return hitFrame.contains(point)
    }
    
}

Usage:

// Needs to be negative to extend _outwards_.
myButton.hitBox = UIEdgeInsets(top: -16, left: -16, bottom: -16, right: -16)