UIButton center text with image (extension)

UIButton.swift

import UIKit

extension UIButton {
  
  func centerTextWithImage (margin:CGFloat) {
    var width = self.frame.width
    var imgWidth = self.imageView!.frame.width as CGFloat
    var txt = self.titleLabel!.text
    var textSize = self.titleLabel!.sizeOfString(txt!, height: Double(self.frame.height)) as CGSize

    var spacing = (width - (imgWidth + textSize.width)) / 2
    self.imageEdgeInsets = UIEdgeInsetsMake(0, margin, 0, spacing);
    self.titleEdgeInsets = UIEdgeInsetsMake(0, spacing + (margin/2), 0, 0);
  }
  
}

Please add extension for sizeOfString.