I forgot to mension override method in PMSuperButton, which is self explanatory:

override open func setTitle(_ title: String?, for state: UIControlState) {
    // setTitle always sets attributed text
    self.setAttributedTitle(getAttributedString(with: title, letterSpacing: letterSpacing), for: state)
}

What do you think, is it ok always setting the attributed string for titleLabel ?

Ohh thanks for this fix. What happens if the user wants to set a custom attributed title? Did he lose all the changes?

I tested your solution, but I think that this can be better:

@IBInspectable open var letterSpacing: CGFloat = 0 {
        didSet {
            self.setTitle(self.titleLabel?.text, for: self.state)
        }
    }

override open func setTitle(_ title: String?, for state: UIControlState) {
        // setTitle always sets attributed text
        if let title = title{
            let attributedStr = NSMutableAttributedString(string: title)
            self.setAttributedTitle(attributedStr, for: self.state)
        }
    }
    
open override func setAttributedTitle(_ title: NSAttributedString?, for state: UIControlState) {
        if let titleAttributed = title{
            let mutableAttributedString = NSMutableAttributedString(attributedString: titleAttributed)
            mutableAttributedString.addAttribute(NSAttributedStringKey.kern, value: letterSpacing, range: NSRange(location: 0, length: mutableAttributedString.length))
            super.setAttributedTitle(mutableAttributedString, for: state)
        }
        else{
            super.setAttributedTitle(title, for: state)
        }
    }

This solution works on all cases that I tested and is more simple and elegant + in future can be added more IBInspectable variables that need use the setAttributedString override method.

What do you think?

In reality, this fixes not manage all the cases, for example, the color change and other adjustments on UIButton. I think we need to remove the letter spacing feature, at least for now.

@codeido, I think we can solve this problem. Let's continue the discussion until we find the best solution. I will try to prepare another solution till the end of this week.

Excellent @mixdesign, consider that everything that impacts the text needs to be "converted" in a NSAttributedString with this approach.

Hey, @codeido
What do you think about this implementation: https://github.com/mixdesign/PMSuperButton/blob/master/Sources/PMSuperButton.swift

It works well with various combinations of programmatically calling setTitle, setAttributedTitle, setTitleColor.

I'm still testing it on my real project, just keep an eye by now.