Is there a way to check if a UIImage has been decompressed? - ios

Question

I'm sure most of you have dealt with forced decompression on a background thread to enhance rendering performance. My question is whether there is a way to check if an image has been decompressed.

Answer 1

It helped me to checked Image has been Decompressed or not by below technique. It is simple code to understand :-
import UIKit
class ViewController: UIViewController {
var compressedImage:NSString?
var decompressedImage:NSString?
override func viewDidLoad() {
super.viewDidLoad()
let image = compressImage()
var imageView = UIImageView(image: image)
//self.view.addSubview(imageView)
let decompressImage = deCompressImage(image: image)
let imageData = Data(UIImagePNGRepresentation(decompressImage)! )
print("***** Size after decompred \(imageData.description) **** ")
imageView = UIImageView(image: decompressImage)
decompressedImage = imageData.description as NSString?
let decompressed = checkImageBeenDecompressed(decompressedImage: decompressedImage!, compressedImage: compressedImage!)
print(decompressed)
//self.view.addSubview(imageView)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func checkImageBeenDecompressed(decompressedImage:NSString , compressedImage:NSString) -> Bool {
let decompressedSize = Int( decompressedImage.getNumFromString()! )
let compressedSize = Int (compressedImage.getNumFromString()! )
if( decompressedSize! > compressedSize! ) {
print("Image has been decompressed")
return true
}
print("Image has not been decompressed")
return false
}
func compressImage() -> UIImage {
let oldImage = UIImage(named: "background.jpg")
var imageData = Data(UIImagePNGRepresentation(oldImage!)! )
print("***** Original Uncompressed Size \(imageData.description) **** ")
imageData = UIImageJPEGRepresentation(oldImage!, 0.025)!
print("***** Compressed Size \(imageData.description) **** ")
compressedImage = imageData.description as NSString?
let image = UIImage(data: imageData)
return image!
}
func deCompressImage(image:UIImage) -> UIImage {
UIGraphicsBeginImageContextWithOptions(image.size, true, 0)
image.draw(at: CGPoint.zero)
let decompressedImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return decompressedImage!
}
}
extension NSString {
func getNumFromString() -> String? {
var numberString: NSString?
let thisScanner = Scanner(string: self as String)
let numbers = NSCharacterSet(charactersIn: "0123456789")
thisScanner.scanUpToCharacters(from: numbers as CharacterSet, into: nil)
thisScanner.scanCharacters(from: numbers as CharacterSet, into: &numberString)
return numberString as? String;
}
}
Demo Reference