UIButtonExtension.swift

extension UIButton {
    // padding - the spacing between the Image and the Title
    func centerTitleVertically(padding: CGFloat = 12.0) {
        guard let imageViewSize = self.imageView?.frame.size, let titleLabelSize = self.titleLabel?.frame.size
            else {
                return
        }
        
        let totalHeight = imageViewSize.height + titleLabelSize.height + padding
        
        self.imageEdgeInsets = UIEdgeInsets(
            top: -(totalHeight - imageViewSize.height) / 2,
            left: 0.0,
            bottom: 0.0,
            right: -titleLabelSize.width
        )
        
        self.titleEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: -imageViewSize.width,
            bottom: -(totalHeight - titleLabelSize.height),
            right: 0.0
        )
        
        self.contentEdgeInsets = UIEdgeInsets(
            top: 0.0,
            left: 0.0,
            bottom: titleLabelSize.height,
            right: 0.0
        )
    }
}