From raw data to UIImagePNGRepresentation in fewer steps

Question

Using this code, I extract an image from a Share Extension and I write it to a directory I created in an App Group.

let content = self.extensionContext!.inputItems[0] as! NSExtensionItem

   let contentType = kUTTypeImage as String

      for attachment in content.attachments as! [NSItemProvider] {

         if attachment.hasItemConformingToTypeIdentifier(contentType) {

            attachment.loadItem(forTypeIdentifier: contentType, options: nil) { data, error in

            // from here
            if error == nil {

               let url = data as! NSURL
               let originalFileName = url.lastPathComponent

               if let imageData = NSData(contentsOf: url as URL) {

                  let img = UIImage(data:imageData as Data)

                  if let data = UIImagePNGRepresentation(img!) {
                     // write, etc.
                                    }

                                }
                            }

                        }

Anything is working fine.

What I'd like to know is if it is possible to reduce some code: in particular, after if error == nil, I:

cast data to NSURL;
use NSURL to get a NSData;
use NSData to get a UIImage;
use UIImage to get a UIImagePNGRepresentation;

Aside from avoiding the creation of the imageData variable, isn't there a way to (safely) achieve the same goal with fewer steps?

You don't need these two steps *use NSData to get a UIImage; use UIImage to get a UIImagePNGRepresentation;* — Midhun MP, Nov 28 '16 at 08:44
@MidhunMP: are you suggesting I can directly write imageData in the final step? — , Nov 28 '16 at 08:54
You can use the NSData got from the server and write that directly — Midhun MP, Nov 28 '16 at 09:16
@IanBell You can still write that data as png, simply give file name as `.png` and write data in Document directory, it will automatically create image with png extension from that data. — Nirav D, Nov 28 '16 at 09:23
@NiravD: I'm not writing to Documents but to a custom directory in an App Group (but I suppose your suggestion is true in any case) — , Nov 28 '16 at 09:29

Nirav D · Accepted Answer · 2016-11-28T09:46:22.483

1

First of all you need to use native Data and URL instead of NSData & NSURL also if you want to write file in DocumentDirectory then you can directly use that imageData no need to make UIImage object from it and then convert it to data using UIImagePNGRepresentation.

if let url = data as? URL, error == nil {

    let originalFileName = url.lastPathComponent
    if let imageData = try? Data(contentsOf: data) {
        // write, etc.
        var destinationURL  = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        destinationURL.appendPathComponent("fileName.png")
        try? imageData.write(to: destinationURL)
    }
}

edited Nov 28 '16 at 09:46

answered Nov 28 '16 at 09:22

Nirav D

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Documents directory is not involved – Nov 28 '16 at 09:30
Moreover, data is of type NSSecureCoding? and I need it as NSURL (or URL) – Nov 28 '16 at 09:38
@IanBell Have you try `data as! URL`? – Nirav D Nov 28 '16 at 09:43
data as URL works, but in your code you don't use it :-) – Nov 28 '16 at 09:44
@IanBell If you doesn't want to write imageData on directory do what you want. – Nirav D Nov 28 '16 at 09:48

From raw data to UIImagePNGRepresentation in fewer steps

1 Answers1