View templated images in Interface Builder

TemplateImageButton.swift

import UIKit

@IBDesignable
class TemplateImageButton: UIButton {

    #if TARGET_INTERFACE_BUILDER
        let templateImageView = UIImageView()
    
        override init(frame: CGRect) {
            super.init(frame: frame)
            addSubview(templateImageView)
        }
        
        required init?(coder aDecoder: NSCoder) {
            super.init(coder: aDecoder)
            addSubview(templateImageView)
        }
    
        override func layoutSubviews() {
            templateImageView.frame = bounds
            templateImageView.image = currentImage?.withRenderingMode(.alwaysTemplate)
        }
    #endif

}