CustomUILabel

import UIKit

enum ScreenType {
    case iPhone4
    case iPhone5
    case iPhone6
    case iPhonePlus
    case iPhoneX
    case unknown
}

class CustomUILabel: UILabel {
    
    override func awakeFromNib() {
        super.awakeFromNib()
        
        switch getScreenType() {
            
        case .iPhone4, .iPhone5:
            font = font.withSize(font.pointSize - 6)
            break
            
        case .iPhone6:
            font = font.withSize(font.pointSize)
            break
            
        case .iPhonePlus, .iPhoneX:
            font = font.withSize(font.pointSize + 6)
            break
            
        default:
            break
        }
    }
    
    func getScreenType() -> ScreenType {
        
        switch UIScreen.main.nativeBounds.height {
            
        case 960:
            return .iPhone4
            
        case 1136:
            return .iPhone5
            
        case 1334:
            return .iPhone6
            
        case 2208:
            return .iPhonePlus
            
        case 2436:
            return .iPhoneX
            
        default:
            return .unknown
        }
    }
}