[UIKit]버튼 Text변경

    @IBAction func btnZoom(_ sender: UIButton) {
        //버튼 Text변경하기
        if !isZoom{
            isZoom = true
            btnValue.setTitle("확대", for: UIControl.State())
        }else{
            isZoom = false
            btnValue.setTitle("축소", for: UIControl.State())
        }
    }