inner shadow

innerShadow.swift

import UIKit
import XCPlayground

extension UIView {
    public func addInnerShadow(topColor: UIColor = UIColor.blackColor().colorWithAlphaComponent(0.3)) {
        let shadowLayer = CAGradientLayer()
        shadowLayer.cornerRadius = layer.cornerRadius
        shadowLayer.frame = bounds
        shadowLayer.frame.size.height = 10.0
        shadowLayer.colors = [
            topColor.CGColor,
            UIColor.whiteColor().colorWithAlphaComponent(0).CGColor
        ]
        layer.addSublayer(shadowLayer)
    }
}

let baseView = UIView(frame: CGRectMake(0,0, 300,300))
baseView.backgroundColor = UIColor.whiteColor()

let view = UIView(frame: CGRectMake(20,20, 100,100))
view.backgroundColor = UIColor.greenColor()
view.layer.cornerRadius = 10.0
//view.layer.shadowColor = UIColor.grayColor().CGColor
view.layer.shadowOpacity = 1.0
view.layer.shadowOffset = CGSizeMake(0, 1.5)
view.layer.shadowRadius = 5.0
view.layer.borderColor = UIColor.greenColor().CGColor
view.layer.borderWidth = 1.0
view.addInnerShadow(UIColor.whiteColor().colorWithAlphaComponent(1.0))

baseView.addSubview(view)
XCPlaygroundPage.currentPage.liveView = baseView