Here is one approach...
Use CoreText functions to get an array of the wrapped-lines from the label. If the last line has at least 1 character, but fewer than 4 characters, and the full text is greater than 4 characters, insert a line-feed 4-characters from the end of the text and update the label.
So, based on a default UILabel
- 17-pt System font - with a fixed-width of 123-pts
and wrapping set to Character Wrap
, it looks like this:

After running the fixLabelWrap(...)
function it looks like this:

Sample code:
class CharWrapViewController: UIViewController {
@IBOutlet var theLabel: UILabel!
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
fixLabelWrap(theLabel)
}
func fixLabelWrap(_ label: UILabel) -> Void {
// get the text from the label
var text = theLabel.text ?? ""
// get an array of the char-wrapped text
let lines = getLinesArrayOfString(in: theLabel)
// if it is more than one line
if lines.count > 1 {
// get the last line
if let lastLine = lines.last {
// if the last line has at least 1 char, is less than 4 chars, and
// the full text is greater than 4 chars
if lastLine.count > 0 && lastLine.count < 4 && text.count > 4 {
// insert a line-feed 4 chars before the end
text.insert("\n", at: text.index(text.endIndex, offsetBy: -4))
// update the text in the label
theLabel.text = text
}
}
}
}
func getLinesArrayOfString(in label: UILabel) -> [String] {
/// An empty string's array
var linesArray = [String]()
guard let text = label.text, let attStr = label.attributedText else { return linesArray }
let rect = label.frame
let frameSetter: CTFramesetter = CTFramesetterCreateWithAttributedString(attStr as CFAttributedString)
let path: CGMutablePath = CGMutablePath()
path.addRect(CGRect(x: 0, y: 0, width: rect.size.width, height: 100000), transform: .identity)
let frame: CTFrame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), path, nil)
guard let lines = CTFrameGetLines(frame) as? [Any] else {return linesArray}
for line in lines {
let lineRef = line as! CTLine
let lineRange: CFRange = CTLineGetStringRange(lineRef)
let range = NSRange(location: lineRange.location, length: lineRange.length)
let lineString: String = (text as NSString).substring(with: range)
linesArray.append(lineString)
}
return linesArray
}
}
Note: the getLinesArrayOfString(...)
function is a slightly modified version of the post found here: https://stackoverflow.com/a/14413484/6257435