Create image with specified color and text inside like Telegram's conversation default avatar

RoundedInitialsAvatar.swift

extension UIImage {
  static func roundedTextAvatar(text: String?,
                        color: UIColor,
                        circular: Bool,
                        textAttributes: [NSAttributedStringKey: Any]?,
                        size: CGSize) -> UIImage? {
    
    let scale = Float(UIScreen.main.scale)
    UIGraphicsBeginImageContextWithOptions(size, false, CGFloat(scale))
    let context = UIGraphicsGetCurrentContext()
    if circular {
      let path = CGPath(ellipseIn: CGRect(origin: CGPoint.zero, size: size), transform: nil)
      context?.addPath(path)
      context?.clip()
    }
    
    // Fill
    context?.setFillColor(color.cgColor)
    context?.fill(CGRect(x: 0, y: 0, width: size.width, height: size.height))
    
    // Text
    if let text = text {
      let attributes = textAttributes ?? [NSAttributedStringKey.foregroundColor: UIColor.white,
                                          NSAttributedStringKey.font: UIFont.systemFont(ofSize: 15.0)]
      
      let textSize = text.size(withAttributes: attributes)
      let bounds = CGRect(origin: CGPoint.zero, size: size)
      let rect = CGRect(x: bounds.size.width/2 - textSize.width/2, 
                        y: bounds.size.height/2 - textSize.height/2,
                        width: textSize.width,
                        height: textSize.height)
      
      text.draw(in: rect, withAttributes: attributes)
    }
    
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    
    return image
  }
}