How to draw a text string using Core Graphics

Paul Hudson    October 26th 2018    @twostraws

To draw text in Core Graphics is trivial because every Swift string has a built-in draw(with:) method that takes an array of attributes and a position and size. There is, like always, some Core Graphics set up work to do, but this next code snippet is a complete example you can re-use easily:

let renderer = UIGraphicsImageRenderer(size: CGSize(width: 512, height: 512))
let img = renderer.image { ctx in
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.alignment = .center

    let attrs = [NSAttributedString.Key.font: UIFont(name: "HelveticaNeue-Thin", size: 36)!, NSAttributedString.Key.paragraphStyle: paragraphStyle]

    let string = "How much wood would a woodchuck\nchuck if a woodchuck would chuck wood?"
    string.draw(with: CGRect(x: 32, y: 32, width: 448, height: 448), options: .usesLineFragmentOrigin, attributes: attrs, context: nil)
}

Available from iOS 4.0 – see Hacking with Swift tutorial 27

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