Swift PDFKit: Unable to scale view to a small size - ios

Question

I am attempting to display a pdf document on a pdfView and would like it to scale such that I can see the full content view within the bounds of the device. However, I am unable to scale it small enough to do so. I have attempted some solutions on SO but still doesn't work.
My implementation so far:
let pdfView: PDFView = {
let v = PDFView()
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
//addSubview and autolayout constraints to superview
if let url = Bundle.main.url(forResource: "documentName", withExtension: "pdf"), let document = PDFDocument(url: url) {
pdfView.document = document
guard let page = document.page(at: 0) else {return}
let pageSize = page.bounds(for: .cropBox)
let screenSize = UIScreen.main.bounds
let scale = screenSize.width / pageSize.width
pdfView.scaleFactor = scale
}
}
Note that these are things I have tried but doesn't work:
pdfView.autoScales = true
pdfView.displayMode = .singlePage
pdfView.minScaleFactor = // to a very small value
I also attempted to iterate the scaleFactor manually by setting 0.01 but realised that the view will not scale lower than 0.25. Is there a way for me to scale even lower? The order of scaling in my appliction is in the order of 0.1-0.2. Thanks.

Answer 1

If I remember correctly, PDFKit seems a bit buggy concerning autoScales. PDFView must be set up in the correct order. You can try:
Add PDFView in subview in viewDidLoad
Set up other PDFView properties, like displayMode, displayDirection, and set up constraint for PDFView in viewWillAppear
Finally, set pdfView.document = document then pdfView.autoScales = true
This setup order work for me.
I don't have answer for your next question. But it could also be related to the setup order. Let me know if it works for you.
Hope this helps.