Why is the image quality so low? (swift) - swift

Question

I didn't like apples image picker so I decided to implement my own. I just finished the stage of getting all the users photos and displaying them in a collection view although I noticed that the difference in image quality is horrible. Here is my code:
import UIKit
import Photos
import PhotosUI
import Foundation
private let reuseIdentifier = "Cell"
var selectedImage = UIImage()
class CollectionVC: UICollectionViewController, UICollectionViewDelegateFlowLayout {
var imageArray = [UIImage]()
override func viewDidLoad() {
super.viewDidLoad()
grapPhotos()
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return imageArray.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath as IndexPath)
let imageView = cell.viewWithTag(1) as! UIImageView
cell.layer.cornerRadius = 4
imageView.image = imageArray[indexPath.row]
return cell
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let selectedImageName = imageArray[indexPath.item]
print(selectedImageName)
selectedImage = selectedImageName
performSegue(withIdentifier: "Custom", sender: self)
}
func grapPhotos() {
let imgManager = PHImageManager.default()
let requestOptions = PHImageRequestOptions()
requestOptions.isSynchronous = true
requestOptions.deliveryMode = .highQualityFormat
let fetchOptions = PHFetchOptions()
fetchOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
fetchOptions.predicate = NSPredicate(format: "mediaType = %d || mediaType = %d", PHAssetMediaType.image.rawValue, PHAssetMediaType.video.rawValue)
if let fetchResult : PHFetchResult = PHAsset.fetchAssets(with: fetchOptions) {
if fetchResult.count > 0 {
for i in 0..<fetchResult.count {
imgManager.requestImage(for: fetchResult.object(at: i), targetSize: CGSize(width: 200, height: 200), contentMode: .aspectFill, options: requestOptions, resultHandler: {
image, error in
self.imageArray.append(image!)
})
}
}
else {
self.collectionView?.reloadData()
print("No Photos")
}
}
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let width = collectionView.frame.width / 3 - 6
return CGSize(width: width, height: width)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 6.0
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 6.0
}
}
I don't really know much about working with images so if anyone could help me out on displaying higher quality images that would be great.

Answer 1

This really works))
for index in 0..<fetchResult.count {
let asset = fetchResult.object(at: index) as PHAsset
let sizeFactor = UIScreen.main.scale
let deviceSize = UIScreen.main.nativeBounds.size
manager.requestImage(for: asset,
targetSize: CGSize(width: deviceSize.width * sizeFactor,
height: deviceSize.height * sizeFactor),
contentMode: .aspectFit,
options: requestOptions,
resultHandler: { (uiimage, info) in
if let image = uiimage {
allImages.append(image)
}
})
}
You only need to know ->
let sizeFactor = UIScreen.main.scale
let deviceSize = UIScreen.main.nativeBounds.size

Answer 2

Image quality depends on the phone your viewing on - retina screens require more pixels. You'll need to multiply your targetSize by UIScreen.main.scale.
Try setting targetSize: CGSize(width: 200 * UIScreen.main.scale, height: 200.0 * UIScreen.main.scale) in your imgManager.requestImage function.
For Retina displays, the scale factor may be 3.0 or 2.0 and one point can represented by nine or four pixels, respectively. For standard-resolution displays, the scale factor is 1.0 and one point equals one pixel.