Decrease the width of the last line in multiline UILabel

Question

I am implemententing a \"read more\" functionality much like the one in Apple\'s AppStore. However, I am using a multiline UILabel. Looking at Apple\'s AppStore

Answer 1

Ive just written a UILabel extension in Swift 4, using a binary search to speed up the substring calculation

It was originally based on the solution by @paul-slm but has diverged considerably

extension UILabel {

func getTruncatingText(originalString: String, newEllipsis: String, maxLines: Int?) -> String {

    let maxLines = maxLines ?? self.numberOfLines

    guard maxLines > 0 else {
        return originalString
    }

    guard self.numberOfLinesNeeded(forString: originalString) > maxLines else {
        return originalString
    }

    var truncatedString = originalString

    var low = originalString.startIndex
    var high = originalString.endIndex
    // binary search substring
    while low != high {
        let mid = originalString.index(low, offsetBy: originalString.distance(from: low, to: high)/2)
        truncatedString = String(originalString[.. Int {
    let oneLineHeight = "A".size(withAttributes: [NSAttributedStringKey.font: font]).height
    let totalHeight = self.getHeight(forString: string)
    let needed = Int(totalHeight / oneLineHeight)
    return needed
}

private func getHeight(forString string: String) -> CGFloat {
    return string.boundingRect(
        with: CGSize(width: self.bounds.size.width, height: CGFloat.greatestFiniteMagnitude),
        options: [.usesLineFragmentOrigin, .usesFontLeading],
        attributes: [NSAttributedStringKey.font: font],
        context: nil).height
}
}