Save PNG files instead of JPEG

Question

I use UIActivityViewController to share my UIImage (save to Photos). I found that quality of saved image is lower then I can see it in my app (it is created by shaders), especially on small details of it. It looks like image is compressed.

The coded is simple:

let items = [img]
let ac = UIActivityViewController(activityItems: items, applicationActivities: nil)

Is it possible to choose PNG lossless format instead of JPEG when it is shared?

Answer 1

Well, solution is quiet simple:

let items = [img.pngData()]