draw text on CAShapelayer - swift

Question

I am drawing a line using coregraphics and I want to draw some text using core graphics.
My code is as follows;
import UIKit
class ArrowLineLayer: CAShapeLayer {
var startingGlyph : CGRect!
override init() {
super.init()
let fontName = "HelveticaNeue-Bold"
let font = UIFont(name:fontName , size: 15)
let measurementString = "28 cm" as NSString
measurementString.draw(at: CGPoint(x:150,y:100), withAttributes: [NSAttributedStringKey.font: font!])
}
func drawArrow(frame:CGRect)
{
self.frame = frame
self.lineWidth = 3
self.strokeColor = UIColor.red.cgColor
self.lineCap = "round"
let path = CGMutablePath()
path.move(to: CGPoint(x:100 , y:100))
path.addLine(to: CGPoint(x:200 , y:100))
let radius: CGFloat = 5.0
let rect = CGRect(x:100 - radius, y: 100 - radius , width: 2 * radius, height: 2 * radius)
startingGlyph = rect
path.addPath(UIBezierPath(ovalIn: rect).cgPath)
self.path = path
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
}
and then later I initialise this layer and add it to main view layer. I can see the line but text is not visible.I don't want to use the CATextlayer because I want to keep the whole logic at one place. Can anyone please point me what I am missing?
Regards,
neena

Answer 1

You can create UIBezierPath with the NSAttributedString and then append this path to your exist path.
extension UIBezierPath {
convenience init(text: NSAttributedString) {
let textPath = CGMutablePath()
let line = CTLineCreateWithAttributedString(text)
let runs = CTLineGetGlyphRuns(line) as! [CTRun]
for run in runs
{
let attributes: NSDictionary = CTRunGetAttributes(run)
let font = attributes[kCTFontAttributeName as String] as! CTFont
let count = CTRunGetGlyphCount(run)
for index in 0 ..< count
{
let range = CFRangeMake(index, 1)
var glyph = CGGlyph()
CTRunGetGlyphs(run, range, &glyph)
var position = CGPoint()
CTRunGetPositions(run, range, &position)
let letterPath = CTFontCreatePathForGlyph(font, glyph, nil)
let transform = CGAffineTransform(translationX: position.x, y: position.y)
textPath.addPath(letterPath!, transform: transform)
}
}
self.init(cgPath: textPath)
}
}