UIKerningTextField.swift

//
//  UIKerningTextField.swift
//  UIKerningTextField
//
//  Created by Damien Laughton
//  Copyright © 2018 Mobilology Limited. No rights reserved.
//

import UIKit

@IBDesignable class UIKerningTextField : UITextField {
    
    @IBInspectable var kerningValue : CGFloat = 3.0 {
        didSet {
            self.configureAttributedText()
        }
    }
    
    override init(frame: CGRect) {
        
        super.init(frame: frame)
        didLoad()
    }
    
    required init?(coder aDecoder: NSCoder) {
        
        super.init(coder: aDecoder)
        didLoad()
    }
    
    override public var text: String? {
        didSet {
            self.configureAttributedText()
        }
    }
    
    func didLoad() {
        self.addTarget(self, action: #selector(UIKerningTextField.configureAttributedText as (UIKerningTextField) -> () -> ()), for: .editingChanged)
        
        self.addTarget(self, action: #selector(UIKerningTextField.configureAttributedText as (UIKerningTextField) -> () -> ()), for: .valueChanged)
    }
    
    @objc func configureAttributedText () {
        let text: String = self.attributedText?.string ?? self.text ?? ""
        let fontSize = self.font?.pointSize ?? 13.0
        let fontName = self.font?.fontName ?? UIFont.systemFont(ofSize: fontSize).fontName
        let fontColor = self.textColor ?? UIColor.black
        
        let font = UIFont(name: fontName, size: fontSize) ?? UIFont.systemFont(ofSize: fontSize)
        
        let attributedText =  NSAttributedString(string: text, attributes: [NSAttributedStringKey.kern:self.kerningValue, NSAttributedStringKey.font:font, NSAttributedStringKey.foregroundColor:fontColor])
        
        self.attributedText = attributedText
    }
    
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
    }
}