Multi line label in Sprite Kit in Swift

SKMultilineLabel.swift

//
//  SKMultilineLabel.swift
//
//  Created by Craig on 10/04/2015.
//  Copyright (c) 2015 Interactive Coconut.
//  MIT License, http://www.opensource.org/licenses/mit-license.php
//
/*   USE:
 (most component parameters have defaults)
 let multiLabel = SKMultilineLabel(text: "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.", labelWidth: 250, pos: CGPoint(x: size.width / 2, y: size.height / 2))
 self.addChild(multiLabel)
 */

import SpriteKit

class SKMultilineLabel: SKNode {
    //props
    var labelWidth:Int {didSet {update()}}
    var labelHeight:Int = 0
    var text:String {didSet {update()}}
    var fontName:String {didSet {update()}}
    var fontSize:CGFloat {didSet {update()}}
    var pos:CGPoint {didSet {update()}}
    var fontColor:UIColor {didSet {update()}}
    var leading:Int {didSet {update()}}
    var alignment:SKLabelHorizontalAlignmentMode {didSet {update()}}
    var dontUpdate = false
    var shouldShowBorder:Bool = false {didSet {update()}}
    //display objects
    var rect:SKShapeNode?
    var labels:[SKLabelNode] = []
    
    init(text:String, labelWidth:Int, pos:CGPoint, fontName:String="ChalkboardSE-Regular",fontSize:CGFloat=10,fontColor:UIColor=UIColor.white,leading:Int? = nil, alignment:SKLabelHorizontalAlignmentMode = .center, shouldShowBorder:Bool = false)
    {
        self.text = text
        self.labelWidth = labelWidth
        self.pos = pos
        self.fontName = fontName
        self.fontSize = fontSize
        self.fontColor = fontColor
        self.leading = leading ?? Int(fontSize)
        self.shouldShowBorder = shouldShowBorder
        self.alignment = alignment
        
        super.init()
        
        self.update()
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    //if you want to change properties without updating the text field,
    //  set dontUpdate to false and call the update method manually.
    func update() {
        if (dontUpdate) {return}
        if (labels.count>0) {
            for label in labels {
                label.removeFromParent()
            }
            labels = []
        }
        let separators = NSCharacterSet.whitespacesAndNewlines
        let words = (text as NSString).components(separatedBy: separators)
        var finalLine = false
        var wordCount = -1
        var lineCount = 0
        while (!finalLine) {
            lineCount+=1
            var lineLength = CGFloat(0)
            var lineString = ""
            var lineStringBeforeAddingWord = ""
            
            // creation of the SKLabelNode itself
            let label = SKLabelNode(fontNamed: fontName)
            // name each label node so you can animate it if u wish
            label.name = "line\(lineCount)"
            label.horizontalAlignmentMode = alignment
            label.fontSize = fontSize
            label.fontColor = fontColor
            
            while lineLength < CGFloat(labelWidth)
            {
                wordCount+=1
                if wordCount > words.count-1
                {
                    //label.text = "\(lineString) \(words[wordCount])"
                    finalLine = true
                    break
                }
                else
                {
                    lineStringBeforeAddingWord = lineString
                    lineString = "\(lineString) \(words[wordCount])"
                    label.text = lineString
                    lineLength = label.frame.width
                }
            }
            if lineLength > 0 {
                wordCount-=1
                if (!finalLine) {
                    lineString = lineStringBeforeAddingWord
                }
                label.text = lineString
                var linePos = pos
                if (alignment == .left) {
                    linePos.x -= CGFloat(labelWidth / 2)
                } else if (alignment == .right) {
                    linePos.x += CGFloat(labelWidth / 2)
                }
                linePos.y += CGFloat(-leading * lineCount)
                label.position = CGPoint(x:linePos.x , y:linePos.y )
                self.addChild(label)
                labels.append(label)
            }
            
        }
        labelHeight = lineCount * leading
        showBorder()
    }
    func showBorder() {
        if (!shouldShowBorder) {return}
        if let rect = self.rect {
            self.removeChildren(in: [rect])
        }
        self.rect = SKShapeNode(rectOf: CGSize(width: labelWidth, height: labelHeight))
        if let rect = self.rect {
            rect.strokeColor = UIColor.white
            rect.lineWidth = 1
            rect.position = CGPoint(x: pos.x, y: pos.y - (CGFloat(labelHeight) / 2.0))
            self.addChild(rect)
        }
        
    }
}

I've updated your code with small visual fixes:

• removing parenthesis when using if and while as it's not needed in Swift
• extracted 2 small functions from update() to comply to standard SwiftLint configuration
• replaced initial if in every function with guard

https://gist.github.com/krodak/0194179ac3142beff54c99bb52209b4a

I'm impressed. I think you should use SKColor as opposed to UIColor, though.

Strange things happens when you set fontSize bigger then 12 - sometimes text is cut or it crashes because of infinite loop (lineCount increments constantly).