uilabel.swift

//: Playground - noun: a place where people can play

import Foundation
import UIKit
import XCPlayground

class DLLabel: UILabel {

    let textContainer = NSTextContainer()
    let layoutManager = NSLayoutManager()
    let textStorage   = NSTextStorage()

    override var frame: CGRect {
        didSet {
            textContainer.size = frame.size
        }
    }

    override var attributedText: NSAttributedString! {
        didSet {
            textStorage.setAttributedString(attributedText)
        }
    }

    override var numberOfLines: Int {
        didSet {
            textContainer.maximumNumberOfLines = numberOfLines
        }
    }

    convenience init() {
        self.init(frame: CGRectZero)
    }

    override init(frame: CGRect) {

        super.init(frame: frame)

        textContainer.lineFragmentPadding = 0
        textContainer.maximumNumberOfLines = numberOfLines
        textContainer.lineBreakMode = lineBreakMode
        textContainer.size = frame.size

        layoutManager.addTextContainer(textContainer)

        textStorage.addLayoutManager(layoutManager)

        userInteractionEnabled = true
    }

    required init(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        let touchPoint = (Array(touches).first! as! UITouch).locationInView(self)
        linkAtPoint(touchPoint)
    }

    func linkAtPoint(var point: CGPoint) {
        let range = layoutManager.glyphRangeForTextContainer(textContainer)

        var textOffset = CGPointZero
        let textBounds = layoutManager.boundingRectForGlyphRange(range, inTextContainer: textContainer)
        let paddingHeight = (self.bounds.size.height - textBounds.size.height) / 2
        if paddingHeight > 0 {
            textOffset.y = paddingHeight
        }

        point = CGPoint(x: point.x - textOffset.x, y: point.y - textOffset.y)

        let index = layoutManager.glyphIndexForPoint(point, inTextContainer: textContainer)

        let string = attributedText.string

        println(string.substringToIndex(advance(string.startIndex, index)))
    }

    override func layoutSubviews() {
        super.layoutSubviews()
        textContainer.size = frame.size
    }
    
}

let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.lineBreakMode = .ByWordWrapping
paragraphStyle.lineSpacing = 10

let font = UIFont(name: "HelveticaNeue", size: 15)!

let string1 = "I ♥ that #RainbowStarDay came back for week 2\n\nhttp://t.co/Am1qlGaYyP\n "

let text1 = NSMutableAttributedString(
    string: string1,
    attributes: [
        NSFontAttributeName: font,
        NSForegroundColorAttributeName: UIColor.blackColor(),
        NSParagraphStyleAttributeName: paragraphStyle
    ])

let text2 = NSAttributedString(
    string: "New on the React blog: an extended introduction to GraphQL by @schrockn\n\nhttps://t.co/iUVyHYBJfQ",
    attributes: [
        NSFontAttributeName: font,
        NSForegroundColorAttributeName: UIColor.blackColor(),
        NSParagraphStyleAttributeName: paragraphStyle
    ])

let text3 = NSAttributedString(
    string: "UC Davis 研究表明貓的呼嚕呼嚕聲（purring）對提高骨密度可能有幫助，建議對宇航員播放類似的 25Hz 低頻聲音。",
    attributes: [
        NSFontAttributeName: font,
        NSForegroundColorAttributeName: UIColor.blackColor(),
        NSParagraphStyleAttributeName: paragraphStyle
    ])

let view = UIView(frame: CGRect(x: 0, y: 0, width: 400, height: 320))

func makeLable() -> UILabel {
    let label = DLLabel()

    label.numberOfLines = 0

    label.tintColor = UIColor.redColor()
    label.layer.borderColor = UIColor.grayColor().CGColor
    label.layer.borderWidth = 1

    view.addSubview(label)

    return label
}

let label1 = makeLable()
label1.frame = CGRect(x: 10, y: 40, width: 100, height: 0)
label1.attributedText = text1
label1.sizeToFit()

let label2 = makeLable()
label2.frame = CGRect(x: 120, y: 40, width: 100, height: 0)
label2.attributedText = text2
label2.sizeToFit()

let label3 = makeLable()
label3.frame = CGRect(x: 230, y: 40, width: 100, height: 0)
label3.attributedText = text3
label3.sizeToFit()

XCPCaptureValue("view", view)