NSTextAttachment

ReplaceChar.swift

// MARK: - String Extension
private extension String {
    /**
     replace characters from the original text to some image
     
     - parameter character: the character that will be used to be replaced by image
     - parameter image: image name that will replace the character
     */
    func replace(char character: String, image: String) -> NSAttributedString {
     
        // search for every check in front of the options
        let regex = try! NSRegularExpression(pattern: character, options: [.IgnoreMetacharacters])
        let items = regex.matchesInString(self, options: [], range: NSRange(location: 0, length: self.characters.count))
        let ranges: [NSRange] = items.map { $0.range }
        
        // replace every check character to new image
        let attributedString = NSMutableAttributedString(string: self)
        for range in ranges.reverse() {
            let attachment = NSTextAttachment()
            attachment.image = UIImage(named: image)
            
            let attributedWithImage = NSAttributedString(attachment: attachment)
            attributedString.replaceCharactersInRange(range, withAttributedString: attributedWithImage)
        }
        
        return attributedString
    }
}