How to find actual number of lines of UILabel?

Question

How can I find the actual number of lines of a UILabel after I have initialized it with a text and a font? I have set its numberOfLines property to 0, so it will expand to however many lines are necessary. But then, how can I find out how many lines it finally got after I set its text?

I found similar questions, but none seems to provide a concise answer and it seems to me that it must be really easy to get it without any overhead on juggling around with the boundingRectWithSize or sizeWithFont,...

Answer 1

None of these worked for me. Below one did,

Swift 4.2:

extension UILabel {     func calculateMaxLines() -> Int {         let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))         let charSize = font.lineHeight         let text = (self.text ?? "") as NSString         let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)         let linesRoundedUp = Int(ceil(textSize.height/charSize))          return linesRoundedUp     }     } 

Swift 4/4.1:

extension UILabel {      func calculateMaxLines() -> Int {         let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))         let charSize = font.lineHeight         let text = (self.text ?? "") as NSString         let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [.font: font], context: nil)         let linesRoundedUp = Int(ceil(textSize.height/charSize))          return linesRoundedUp     }  } 

Swift 3:

extension UILabel {      func calculateMaxLines() -> Int {         let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))         let charSize = font.lineHeight         let text = (self.text ?? "") as NSString         let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)         let linesRoundedUp = Int(ceil(textSize.height/charSize))          return linesRoundedUp     }  } 

Answer 2

Swift 5 (IOS 12.2)

Get max number of lines required for a label to render the text without truncation.

extension UILabel {     var maxNumberOfLines: Int {         let maxSize = CGSize(width: frame.size.width, height: CGFloat(MAXFLOAT))         let text = (self.text ?? "") as NSString         let textHeight = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [.font: font], context: nil).height         let lineHeight = font.lineHeight         return Int(ceil(textHeight / lineHeight))     } } 

Get max number of lines can be displayed in a label with constrained bounds. Use this property after assigning text to label.

extension UILabel {     var numberOfVisibleLines: Int {         let maxSize = CGSize(width: frame.size.width, height: CGFloat(MAXFLOAT))         let textHeight = sizeThatFits(maxSize).height         let lineHeight = font.lineHeight         return Int(ceil(textHeight / lineHeight))     } } 

Usage

print(yourLabel.maxNumberOfLines) print(yourLabel.numberOfVisibleLines)