Use of system symbol image

gistfile1.txt

@IBAction func playOrPause(_ sender: Any) {
        let playPauseImageConfig = UIImage.SymbolConfiguration(pointSize: self.view.frame.height * relativePointSizeConstant, weight: .regular, scale: .large)
        let pauseImage = UIImage(systemName: "pause.fill", withConfiguration: playPauseImageConfig)
        let playImage = UIImage(systemName: "play.fill", withConfiguration: playPauseImageConfig)
        
        // if timer is not running then start timer
        if (timerIsPaused) {
            playPauseBtn.setImage(pauseImage, for: .normal)
            timer = Timer.scheduledTimer(timeInterval: 1.0, target: self, selector: #selector(startTimer), userInfo: nil, repeats: true)
            timerIsPaused = false
        }
        // if timer is running then pause timer
        else {
            playPauseBtn.setImage(playImage, for: .normal)
            timer?.invalidate()
            timerIsPaused = true
        }
    }