How to check current font size of UILabel?

Question

I have 3 UILabels and I want to set same (the smallest one from all of 3 possibilities) font for all of them. What is the problem? I don\'t know how to check the cu

Answer 1

This is one way to get the current size of the UILabel pointsize although I know of more ways if this does not work. This is the cleanest and fastest. See example and extension included.

import UIKit

class ViewController: UIViewController {

    lazy var label1 : UILabel = {
        let lbl = UILabel(frame: CGRect(x: 20, y: 80, width: self.view.bounds.width - 40, height: 40))
        lbl.text = "This is some large text to make it fit to size with a big font size"
        lbl.font = UIFont.systemFont(ofSize: 50, weight: .bold)
        lbl.textColor = .black
        lbl.minimumScaleFactor = 0.01
        lbl.adjustsFontSizeToFitWidth = true
        lbl.numberOfLines = 0
        return lbl
    }()

    lazy var label2 : UILabel = {
        let lbl = UILabel(frame: CGRect(x: 20, y: label1.frame.maxY + 5, width: self.view.bounds.width - 40, height: 40))
        lbl.text = "This is one line"
        lbl.font = UIFont.systemFont(ofSize: 20, weight: .bold)
        lbl.textColor = .black
        lbl.minimumScaleFactor = 0.01
        lbl.adjustsFontSizeToFitWidth = true
        lbl.numberOfLines = 0
        return lbl
    }()

    lazy var label3 : UILabel = {
        let lbl = UILabel(frame: CGRect(x: 20, y: label2.frame.maxY + 10, width: self.view.bounds.width - 40, height: 80))
        lbl.text = "This is some large text to make it fit to size with a big font size"
        lbl.font = UIFont.systemFont(ofSize: 100, weight: .bold)
        lbl.textColor = .black
        lbl.minimumScaleFactor = 0.01
        lbl.adjustsFontSizeToFitWidth = true
        lbl.numberOfLines = 0
        return lbl
    }()


    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.view.addSubview(label1)
        self.view.addSubview(label2)
        self.view.addSubview(label3)

        var minSize : CGFloat = .greatestFiniteMagnitude
        for sub in self.view.subviews{
            if let lbl = sub as? UILabel{
                //get the size
                let font = lbl.adjustedFont()
                print("the size is \(font.pointSize)")
                minSize = min(font.pointSize,minSize)
            }
        }
        print("the minimum for all fonts is \(minSize)")
        print("i am going to delay for 3 seconds and then reset all the labels to the minimum size :)")
        DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 3.0) {
            for sub in self.view.subviews{
                if let lbl = sub as? UILabel{
                    lbl.font = lbl.font.withSize(minSize)
                }
            }
        }
    }
}
extension UILabel{
    func adjustedFont()->UIFont {
        guard let txt = text else {
            return self.font
        }
        let attributes: [NSAttributedString.Key: Any] = [.font: self.font]
        let attributedString = NSAttributedString(string: txt, attributes: attributes)
        let drawingContext = NSStringDrawingContext()
        drawingContext.minimumScaleFactor = self.minimumScaleFactor
        attributedString.boundingRect(with: bounds.size,
                                      options: [.usesLineFragmentOrigin,.usesFontLeading],
                                      context: drawingContext)

        let fontSize = font.pointSize * drawingContext.actualScaleFactor
        return font.withSize(CGFloat(floor(Double(fontSize))))
    }
}

Example in Action