Adventures in PDF: Swift and PDFKit

Working with PDFs in OS X is straightforward using PDFKit (update: and in iOS since iOS 11).

PDFDocument

It all starts with the PDFDocument class and in order to leverage this you simply import Quartz and get started. Like so:

import Quartz

let url = NSBundle.mainBundle().URLForResource("myPDF", withExtension: "pdf")
let pdf = PDFDocument(URL: url)
pdf.pageCount() // number of pages in document
pdf.string() // entire text of document

As you can see counting the number of pages and accessing the text is straightforward and there's plenty more to explore alongside this, but I want to move quickly along to working with pages.

PDFPage

While you can access a string of the entire document and this is useful for searches, more often you'll want to work with PDFPage instances. You access pages by their index:

import Quartz

let url = NSBundle.mainBundle().URLForResource("myPDF", withExtension: "pdf")
let pdf = PDFDocument(URL: url)
let page = pdf.pageAtIndex(10) // returns a PDFPage instance
page.attributedString() // attributed string for the PDFPage instance

You could convert an entire PDF to a single NSAttributedString:

import Quartz

let url = NSBundle.mainBundle().URLForResource("myPDF", withExtension: "pdf")
let pdf = PDFDocument(URL: url)
let docStr = NSMutableAttributedString()
for i in 0..<pdf.pageCount() {
    docStr.appendAttributedString(doc.pageAtIndex(i).attributedString())
}

but this would take a good deal of time for a long PDF and if you are looking to simply display the PDF then PDFView is the class you're looking for.

PDFView

Creating a PDFView is once again a straightforward thing to do:

import Quartz

let url = NSBundle.mainBundle().URLForResource("myPDF", withExtension: "pdf")
let pdf = PDFDocument(URL: url)
let view = PDFView(frame: CGRect(x: 0, y: 0, width: 500, height: 750))
view.setDocument(pdf)

PDF Extras

Beyond the document, page and view classes there are PDFOutline, PDFSelection, and PDFAnnotation. The latter being a superclass of twelve further classes. Completing the PDFKit classes there's also PDFBorder, which is used for adding decoration to annotations.

To explore in depth read through the PDFKit Programming Guide.

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