PHAsset image comes pixelated while showing it in CollectionView - ios

Question

I have this code which I am using in collectionView to get the image.
// Code in CollectionView's cellForItemAtIndex
// Image
PHImageManager.defaultManager().getPhoto(asset, size: cell.thumbnail.frame.size) { (image) in
if let properImage = image
{
dispatch_async(dispatch_get_main_queue(), {
cell.thumbnail.image = properImage
})
}
else
{
cell.thumbnail.image = UIImage()
}
}
And the getPhoto method.
//MARK: PHImageManager
extension PHImageManager
{
func getPhoto( asset : PHAsset, size : CGSize, completion : (image : UIImage?) -> ())
{
let options = PHImageRequestOptions()
options.networkAccessAllowed = true
options.synchronous = false
options.resizeMode = PHImageRequestOptionsResizeMode.Exact
options.deliveryMode = PHImageRequestOptionsDeliveryMode.HighQualityFormat
_ = self.requestImageForAsset(asset, targetSize: size, contentMode: PHImageContentMode.AspectFit, options: options, resultHandler: {
result , _ in
if let resultValue = result as UIImage?
{
completion(image: resultValue)
}
else
{
completion(image: nil)
}
})
}
}
Whenever I load images into collectionView, I can see that the visible cell's images are pixelated. When I scroll thorough the images it appeared properly with high quality image.
Also I have tried all combinations of resizeMode and deliveryMode, didn't help me. I have tried by enabling synchronous too.
I want to show hight quality images in the first time itself. I don't want to scroll through the collectionView to get it.
Is there any way to solve this? Thanks in advance.

Answer 1

You need to scale your image size depending on the scale of your screen like this:
let retinaMultiplier = UIScreen.main.scale
let size = CGSize(width:self.bounds.size.width * retinaMultiplier, height: self.bounds.size.height * retinaMultiplier)
and pass this size into targetSize of your requestImageForAsset method.
And be sure you chose the right options for assets fetching.