forjb.swift

import UIKit

extension String {
    func toAttributed() -> NSAttributedString {
        return NSAttributedString(string: self)
    }
}

extension NSAttributedString {
    func toImage(withAlpha alpha: CGFloat = 1.0) -> UIImage {
        return UIGraphicsImageRenderer(size: self.size())
            .image { context in
                context.cgContext.setAlpha(alpha)
                self.draw(at: .zero)
        }
    }
    
    func renderToAttachment(withAlpha alpha: CGFloat = 1.0) -> NSAttributedString {
        let image = self.toImage()
        let attachment: NSTextAttachment = {
            $0.image = image
            $0.bounds = CGRect(origin: .zero, size: image.size)
            return $0
        }(NSTextAttachment())
        
        return NSAttributedString(attachment: attachment)
    }
}

let string = NSMutableAttributedString(string: "")
string.append("😀😀😀".toAttributed().renderToAttachment())
string.append("😀😀😀".toAttributed().renderToAttachment(withAlpha: 0.5))
string