Autoshrink fontsize of UILabeltext siwft - swift

Question

I have a multiline UILabel text which expands dynamically according to the text length. I have setup proper auto layout in storyboard and grows bigger if the text is lengthy.
But i want to reduce the font size to 24 if its 2-line and to 20 if its 3-line text.
If text is single line then, font size should be 34.
I tried minimum font scale = 20/34 = .58
but no use. Please suggest a solution

Answer 1

You could use a switch statement to determine the font size when a certain number of lines have been after changing the label's text.
Using the actualNumberOfLines() algorithm from https://stackoverflow.com/a/60993649/12783209 allows you to redeclare the font for this label whenever necessary.
func changeFontSizeIfNeeded(on label: inout UILabel){
switch label.actualNumberOfLines{
case 2:
label.font = label.font.withSize(24)
case 3:
label.font = label.font.withSize(20)
default:
//Change this to be the default font size
label.font = label.font.withSize(30)
}
}
And add this extension to your project:
extension UILabel{
func actualNumberOfLines()-> Int {
// You have to call layoutIfNeeded() if you are using autoLayout
self.layoutIfNeeded()
let myText = self.text! as NSString
let rect = CGSize(width: self.bounds.width, height: CGFloat.greatestFiniteMagnitude)
let labelSize = myText.boundingRect(with: rect, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: self.font as Any], context: nil)
return Int(ceil(CGFloat(labelSize.height) / self.font.lineHeight))
}
}