Easy to use extension on swift 3
extension CALayer {
func addGradienBorder(colors:[UIColor] = [UIColor.red,UIColor.blue], width:CGFloat = 1) {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = CGRect(origin: .zero, size: self.bounds.size)
gradientLayer.startPoint = CGPoint(x:0.0, y:0.5)
gradientLayer.endPoint = CGPoint(x:1.0, y:0.5)
gradientLayer.colors = colors.map({$0.cgColor})
let shapeLayer = CAShapeLayer()
shapeLayer.lineWidth = width
shapeLayer.path = UIBezierPath(rect: self.bounds).cgPath
shapeLayer.fillColor = nil
shapeLayer.strokeColor = UIColor.black.cgColor
gradientLayer.mask = shapeLayer
self.addSublayer(gradientLayer)
}
}
use to your view, example
yourView.addGradienBorder(color: UIColor.black, opacity: 0.1, offset: CGSize(width:2 , height: 5), radius: 3, viewCornerRadius: 3.0)