Get dimensions of a PDF being displayed in QLPreview Controller

Question

I need to figure out a way to get the size(dimensions) of the file being shown in the QLPreview Controller. If I use qlpreviewController.frame it just returns the dimensions of the QLPreview not the content (in my case, its a PDF).

Will I require subclassing the QLPreview or maybe use a UIWebView instead ?

My aim is that I have a subview that is draggable and I want to place it on top of the PDF file and get the relative dimensions (X and Y) with respect to the PDF that is being shown.

How should i approach this ?

This is the screenshot for the current scenarios.

How do I get the relative position of my draggable view(TEST) with respect to PDF ?

I have added my custom draggable view as a subview in the QLPreviewController like:

qlCntrl.view.addSubview(draggableTestView)

Do you need to know the dimensions of the pdf? Printable size? — Leo Dabus, Nov 27 '17 at 15:49
if i can get that in pixels then yes but how can i relate it to a view thats rotating above my pdf — Umar Farooque, Nov 27 '17 at 15:51
You are not showing any code how could I answer that? Btw you should show what you have tried and the issues you are facing. — Leo Dabus, Nov 27 '17 at 15:52
You can check the proportion (percentage) of your drawing to the canvas (the device screen) and its position and compare it with your pdf size. — Leo Dabus, Nov 27 '17 at 16:01
my main concern is that I wanna export the pdf with my custom image added to it. I have already tested and have the code for that but in order to do so I need to supply the coordinates of my image view, which are relative to the view but not the size of my PDF document — Umar Farooque, Nov 27 '17 at 16:04
PDF size of A4 document is 595 * 842 but how do i relate that to my view — Umar Farooque, Nov 27 '17 at 16:05

score 1 · Answer 1 · answered Nov 27 '17 at 18:37

This is not possible. QLPreviewController does not expose any information about the content being shown. (In fact, the content is sometimes not actually shown by your app, but by a system service instead).

If you know you are dealing with a PDF, you can use PDFKit instead : https://developer.apple.com/documentation/pdfkit

Get dimensions of a PDF being displayed in QLPreview Controller

1 Answers1