Outline UILabel text in UILabel Subclass

Question

I\'m trying hard to find a way to simply add an outline/stroke/contour to my UILabel text. Talking about a stroke around the letters of the text not around the background of

Answer 1

Below is what I used in my App written in Swift 4.1

Swift 4.x

let strokeTextAttributes: [NSAttributedStringKey: Any] = [
    NSAttributedStringKey.strokeColor: UIColor.black,
    NSAttributedStringKey.foregroundColor : UIColor.white,
    NSAttributedStringKey.strokeWidth : -3.0,
    NSAttributedStringKey.font : UIFont.boldSystemFont(ofSize: 18)
]

Answer 2

Update to Swift 5

This answer is built on Anandnimje and J.Doe answers, and is meant to update and streamline it to make the usage clearer and simpler.

Simply use these two functions:

func outline(string:String, font:String, size:CGFloat, outlineSize:Float, textColor:UIColor, outlineColor:UIColor) -> NSMutableAttributedString {
    return NSMutableAttributedString(string:string,
                                     attributes: outlineAttributes(font: UIFont(name: font, size: size)!,
                                                        outlineSize: outlineSize, textColor: textColor, outlineColor: outlineColor))
}

func outlineAttributes(font: UIFont, outlineSize: Float, textColor: UIColor, outlineColor: UIColor) -> [NSAttributedString.Key: Any]{
    return [
        NSAttributedString.Key.strokeColor : outlineColor,
        NSAttributedString.Key.foregroundColor : textColor,
        NSAttributedString.Key.strokeWidth : -outlineSize,
        NSAttributedString.Key.font : font
    ]
}

Then use outline with your labels as the following:

label.attributedText = outline(string: "Label Text", font: "HelveticaNeue", size: 14, outlineSize: 4, textColor: .white, outlineColor: .black)

Answer 3

Here you have class with implementation, copy and paste to playgrond for test:

    class StrokedLabel: UILabel {

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

                let customizedText = NSMutableAttributedString(string: newValue,
                                                               attributes: strokeTextAttributes)


                attributedText = customizedText
            }
        }
    }


//////////// PLAYGROUND IMPLEMENTATION PART /////////
    let text = "Stroked text"

// UILabel subclass initialization
    let label = StrokedLabel(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
// simple assign String to 'strockedText' property to see the results
    label.strockedText = text

    label.backgroundColor = UIColor.white


    label

Swift 4.2

import UIKit

class StrokedLabel: UILabel {

var strockedText: String = "" {
    willSet(newValue) {
        let strokeTextAttributes : [NSAttributedString.Key : Any] = [
            NSAttributedString.Key.strokeColor : UIColor.black,
            NSAttributedString.Key.foregroundColor : UIColor.white,
            NSAttributedString.Key.strokeWidth : -4.0,
            NSAttributedString.Key.font : UIFont.boldSystemFont(ofSize: 30)
            ] as [NSAttributedString.Key  : Any]

        let customizedText = NSMutableAttributedString(string: newValue,
                                                       attributes: strokeTextAttributes)


        attributedText = customizedText
    }
}

}

//////////// PLAYGROUND IMPLEMENTATION PART /////////
  let text = "Stroked text"

  // UILabel subclass initialization
  let label = StrokedLabel(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
  // simple assign String to 'strockedText' property to see the results
  label.strockedText = text

  label.backgroundColor = UIColor.clear


  label

Maybe refactoring for this class will be welcomed, but should work for you at this form

As you can see usage is very convenient.

Answer 4

@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.

Answer 5

Your code works for me if I set the type of the attributes dictionary, like this:

let strokeTextAttributes: [String: Any] = [
  // etc...
]

Maybe that's all your missing?

Answer 6

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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