TextKit 2: NSTextLayoutManager only gives 1 incorrect text fragment

My goal is to be able to tap on words accurately.... I'm having a small nightmare with TextKit not providing frames for fragments in the way I'd expect, it's clear I'm not setting it up correctly but I can't find the parameter that is causing it.

The NSTextLayoutFragment it returns is just for the first single line in its entirety, I'd like the frames of each word / character / word fragment / whatever it can do to achieve the goal.

class Label: UILabel {

    private var textStorage: NSTextContentStorage? {
        guard let attributedText else { return nil }
        let textStorage = NSTextContentStorage()
        let textContainer = NSTextContainer()
        let textLayoutManager = NSTextLayoutManager()

       // textContainer.size = bounds.size // neither works, nor does 0.0
        textContainer.size = CGSize(width: bounds.size.width, 
                                    height: .greatestFiniteMagnitude)
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = lineBreakMode
       // textContainer.widthTracksTextView = false // makes no difference
        textLayoutManager.textContainer = textContainer
        textStorage.addTextLayoutManager(textLayoutManager)
        textStorage.attributedString = attributedText
       // textStorage.textStorage?.append(attributedText)
        
        return textStorage
    }


    public var characterMap: [CGRect] {
        
        setNeedsLayout()
        layoutIfNeeded()
        
        guard let textStorage,
              let layoutManager = textStorage.textLayoutManagers.first,
              let textContainer = layoutManager.textContainer else { return [] }

        
        layoutManager.enumerateSubstrings(from: textStorage.documentRange.location,
                                          options: [.byWords]) { string, range, textRange, pointer in
            print("String:", string, range, textRange)
        }
        
        var rects = [CGRect]()

        layoutManager.enumerateTextLayoutFragments(from: layoutManager.documentRange.endLocation,
                                                   options: [.reverse, .ensuresLayout]) { layoutFragment in
            rects.append(layoutFragment.layoutFragmentFrame)
            return true
        }

        print("TextFrame:", textContainer.size)
        print(rects)
        return rects
    }

Test string:

"Lorem ipsum dolor ⚡️ sit amet, www.google.com consectetur 🌧😭 adipiscing elit"

layoutManager.enumerateSubstrings works correctly, I get a list of words like this...

String: Optional("Lorem") 0...5 Optional(NSCountableTextRange: {0, 6})
String: Optional("ipsum") 6...11 Optional(NSCountableTextRange: {6, 6})
String: Optional("dolor") 12...17 Optional(NSCountableTextRange: {12, 9})
String: Optional("sit") 21...24 Optional(NSCountableTextRange: {21, 4})
String: Optional("amet") 25...29 Optional(NSCountableTextRange: {25, 6})
String: Optional("www.google.com") 31...45 Optional(NSCountableTextRange: {31, 15})
String: Optional("consectetur") 46...57 Optional(NSCountableTextRange: {46, 17})
String: Optional("adipiscing") 63...73 Optional(NSCountableTextRange: {63, 11})
String: Optional("elit") 74...78 nil

textContainer.size is also correct TextFrame: (361.0, 133.66666666666666)

but layoutManager.enumerateTextLayoutFragments returns only this

[(0.0, 0.0, 357.0078125, 33.4140625)]

What am I missing to get the layoutManager to fragment the way I'd like it? I've tried TextKit 1 and I had the same problem, the scope is limited to the first line.

Solution

Ok I've found the reason for the single line... it was the attributedText that overrode the lineBreakMode with its paragraphStyle

    private var textStorage: NSTextStorage? {
        guard let attributedText,
              let lineBreakMode = (attributes[.paragraphStyle] as? NSMutableParagraphStyle)?.lineBreakMode
        else { return nil }
        
        let layoutManager = NSLayoutManager()
        let textStorage = NSTextStorage(attributedString: attributedText)
        let textContainer = NSTextContainer(size: CGSize(width: bounds.size.width,
                                                         height: CGFloat.greatestFiniteMagnitude))
        textContainer.lineFragmentPadding = 0
        textContainer.maximumNumberOfLines = numberOfLines
        textContainer.lineBreakMode = lineBreakMode
        
        layoutManager.addTextContainer(textContainer)
        textStorage.addLayoutManager(layoutManager)
        
        return textStorage
    }
    
    private var textContentStorage: NSTextContentStorage? {
        
        guard let attributedText,
              let lineBreakMode = (attributes[.paragraphStyle] as? NSMutableParagraphStyle)?.lineBreakMode
        else { return nil }
                
        let textStorage = NSTextContentStorage()
        let textLayoutManager = NSTextLayoutManager()
        let textContainer = NSTextContainer(size: CGSize(width: bounds.size.width,
                                                         height: CGFloat.greatestFiniteMagnitude))

        textStorage.attributedString = attributedText
        textContainer.lineFragmentPadding = 0.0
        textContainer.lineBreakMode = lineBreakMode // numberOfLines == 1 ? .byTruncatingTail : .byWordWrapping
        textContainer.maximumNumberOfLines = numberOfLines
        
        textLayoutManager.textContainer = textContainer
        textStorage.addTextLayoutManager(textLayoutManager)
        textLayoutManager.ensureLayout(for: textStorage.documentRange)
        textLayoutManager.textViewportLayoutController.layoutViewport()
        
        return textStorage
    }

I used a mixture of TextKit 1 and TextKit 2 to get the word rects... behold!

    public var wordMap: [CGRect] {

//        setNeedsLayout() // up to you if you want to assume layout or not
//        layoutIfNeeded()
        
        guard let textStorage,
              let layoutManager = textStorage.layoutManagers.first,
              let textContainer = layoutManager.textContainers.first,
              let textContentStorage,
              let textLayoutManager = textContentStorage.textLayoutManagers.first else { return [] }
   
        var ranges = [NSRange]()
        textLayoutManager.enumerateSubstrings(from: textContentStorage.documentRange.location,
                                          options: [.byWords]) { string, range, textRange, pointer in
            let start = textLayoutManager.offset(from: textContentStorage.documentRange.location,
                                                 to: range.location)
            let length = textLayoutManager.offset(from: range.location,
                                                  to: range.endLocation)
            ranges.append(NSRange(location: start, length: length))
        }

        return ranges.map { layoutManager.boundingRect(forGlyphRange: $0, in: textContainer) }
    }