HyperlinkLabel.swift

private func url(at touches: Set<UITouch>) -> URL? {
  guard let attributedText = attributedText, attributedText.length > 0 else { return nil }
  guard let touchLocation = touches.sorted(by: { $0.timestamp < $1.timestamp } ).last?.location(in: self) else { return nil }
  guard let textStorage = preparedTextStorage() else { return nil }
  let layoutManager = textStorage.layoutManagers[0]
  let textContainer = layoutManager.textContainers[0]
        
  let characterIndex = layoutManager.characterIndex(for: touchLocation, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
  guard characterIndex >= 0, characterIndex != NSNotFound else { return nil }

  // Glyph index is the closest to the touch, therefore also validate if we actually tapped on the glyph rect
  let glyphRange = layoutManager.glyphRange(forCharacterRange: NSRange(location: characterIndex, length: 1), actualCharacterRange: nil)
  let characterRect = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer)
  guard characterRect.contains(touchLocation) else { return nil }
        
  // Link styled by Apple
  if let url = textStorage.attribute(.link, at: characterIndex, effectiveRange: nil) as? URL {
    return url
  }
  // Custom link style
  return textStorage.attribute(.hyperlink, at: characterIndex, effectiveRange: nil) as? URL
}