Outline UILabel text in UILabel Subclass

@anandnimje answer converted to Swift 4.2 and wrapped it into a function:

public func stroke(font: UIFont, strokeWidth: Float, insideColor: UIColor, strokeColor: UIColor) -> [NSAttributedStringKey: Any]{
    return [
        NSAttributedStringKey.strokeColor : strokeColor,
        NSAttributedStringKey.foregroundColor : insideColor,
        NSAttributedStringKey.strokeWidth : -strokeWidth,
        NSAttributedStringKey.font : font
        ]
}

Usage:

label.attributedText = NSMutableAttributedString(string: "Hello World", 
attributes: stroke(font: UIFont(name: "SourceSansPro-Black", size: 20)!, 
strokeWidth: 4, insideColor: .white, strokeColor: .black))

Make sure you have the right name for your UIFont, else it crashes. Should never be a problem if you have the right name.

This code works for me.

Swift 3

let strokeTextAttributes = [
  NSStrokeColorAttributeName : UIColor.black,
  NSForegroundColorAttributeName : UIColor.white,
  NSStrokeWidthAttributeName : -4.0,
  NSFontAttributeName : UIFont.boldSystemFont(ofSize: 30)
] as [String : Any]

myLabel.attributedText = NSMutableAttributedString(string: "Test me i have color.", attributes: strokeTextAttributes)

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Swift 4.2 & 5.1

let strokeTextAttributes = [
  NSAttributedString.Key.strokeColor : UIColor.red,
  NSAttributedString.Key.foregroundColor : UIColor.white,
  NSAttributedString.Key.strokeWidth : -4.0,
  NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 30)]
  as [NSAttributedString.Key : Any]

labelOutLine.attributedText = NSMutableAttributedString(string: "Your outline text", attributes: strokeTextAttributes)

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