Convenient Swift method to run a closure of UI-optimizing code on some devices selectively based on their logical height

README.md

The gist provides a convenient Swift method to run a closure of UI-optimizing code on some devices selectively based on their logical height. The usage examples show:

• How to use the method to scale a view designed for iPhone 6+ to display on other devices. This is generally not recommended in production because scaling does not give good visual results.
• Adjust a UIImageView's contentMode on iPhone 5 (SE, 5s, 5c, etc) and below.

DeviceOptimizer.swift

//
//  DeviceOptimizer.swift
//
//  Created by Thanh Pham on 8/4/16.
//

import UIKit

struct DeviceOptimizer {

    enum DeviceHeightType: CGFloat {
        case iPhone4 = 640
        case iPhone5 = 568
        case iPhone6 = 667
        case iPhone6Plus = 736
    }

    static func optimizeForDevicesWithHeight(comparator: (CGFloat, CGFloat) -> Bool, _ deviceHeightType: DeviceHeightType, @noescape closure: Void -> Void) {
        guard comparator(UIScreen.mainScreen().bounds.height, deviceHeightType.rawValue) else {
            return
        }
        closure()
    }
}

Usage.swift

DeviceOptimizer.optimizeForDevicesWithHeight(!=, .iPhone6Plus) {
    let screenSize = UIScreen.mainScreen().bounds.size
    let height = DeviceOptimizer.DeviceHeightType.iPhone6Plus.rawValue
    view.bounds = CGRectMake(0, 0, screenSize.width / screenSize.height * height, height)
    let scale = screenSize.height / height
    view.transform = CGAffineTransformMakeScale(scale, scale)
}

DeviceOptimizer.optimizeForDevicesWithHeight(<=, .iPhone5) {
    imageView.contentMode = .ScaleAspectFit
}