ios swift Image compression

ImageCompression.swift

//: Playground - noun: a place where people can play

import UIKit

do{
    func compressImage(_ img:UIImage) -> UIImage? {
        // Reducing file size to a 10th
        var actualHeight: CGFloat = img.size.height
        var actualWidth: CGFloat = img.size.width
        let maxHeight: CGFloat = 1136.0
        let maxWidth: CGFloat = 640.0
        var imgRatio: CGFloat = actualWidth/actualHeight
        let maxRatio: CGFloat = maxWidth/maxHeight
        var compressionQuality: CGFloat = 0.5
        
        if actualHeight > maxHeight || actualWidth > maxWidth {
            if imgRatio < maxRatio {
                //adjust width according to maxHeight
                imgRatio = maxHeight / actualHeight
                actualWidth = imgRatio * actualWidth
                actualHeight = maxHeight
            } else if imgRatio > maxRatio {
                //adjust height according to maxWidth
                imgRatio = maxWidth / actualWidth
                actualHeight = imgRatio * actualHeight
                actualWidth = maxWidth
            } else {
                actualHeight = maxHeight
                actualWidth = maxWidth
                compressionQuality = 1
            }
        }
        let rect = CGRect(x: 0.0, y: 0.0, width: actualWidth, height: actualHeight)
        UIGraphicsBeginImageContext(rect.size)
        img.draw(in: rect)
        guard let img = UIGraphicsGetImageFromCurrentImageContext() else {
            return nil
        }
        UIGraphicsEndImageContext()
        guard let imageData = UIImageJPEGRepresentation(img, compressionQuality) else {
            return nil
        }
        return UIImage(data: imageData)
    }
   //compressImage(UIImage(named: "tst.jpg")!)
    
  
}