Swift - Overlay Text on current PDF Document - swift

Question

I have been trying to simply overlay text onto a current PDF document that is essentially a timecard. I copy the file to the downloads folder and that works fine, but then when I try to use a CGContext to add text, it exports a white PDF document. Can anyone see where I'm going wrong?
do {
try fileManager.copyItem(at: pdfURL!, to: destinationURL)
} catch let error as NSError {
print("Copy failed :( with error: \(error)")
}
if let pdf: CGPDFDocument = CGPDFDocument(destinationURL as CFURL) { // Create a PDF Document
if pdf.numberOfPages == 1 {
let pdfPage: CGPDFPage = pdf.page(at: 1)!
let pageRect = pdfPage.getBoxRect(CGPDFBox.mediaBox)
//print(pageRect)
let context = CGContext.init(destinationURL as CFURL, mediaBox: nil, nil)
let font = NSFont(name: "Helvetica Bold", size: 20.0)
let textRect = CGRect(x: 250, y: 250, width: 500, height: 40)
let paragraphStyle: NSParagraphStyle = NSParagraphStyle.default
let textColor = NSColor.black
let textFontAttributes = [
NSAttributedStringKey.font: font!,
NSAttributedStringKey.foregroundColor: textColor,
NSAttributedStringKey.paragraphStyle: paragraphStyle
]
let text: NSString = "Hello world"
text.draw(in: textRect, withAttributes: textFontAttributes)
context?.addRect(textRect)
context?.closePDF()
}
}

Answer 1

The following code is what I used to overlay text on macOS. I've been trying to find a link to the source answer I got this from. If I find it I'll edit this answer with a link.
// Confirm there is a document there
if let doc: PDFDocument = PDFDocument(url: srcURL) {
// Create a document, get the first page, and set the size of the page
let page: PDFPage = doc.page(at: 0)!
var mediaBox: CGRect = CGRect(x: 0, y: 0, width: 792, height: 612)
// This is where the magic happens. Create the drawing context on the PDF
let context = CGContext(dstURL as CFURL, mediaBox: &mediaBox, nil)
let graphicsContext = NSGraphicsContext(cgContext: context!, flipped: false)
NSGraphicsContext.current = graphicsContext
context!.beginPDFPage(nil)
// Draws the PDF into the context
page.draw(with: .mediaBox, to: context!)
// Parse and Draw Text on the context
drawText()
context!.saveGState()
context!.restoreGState()
context!.endPDFPage()
NSGraphicsContext.current = nil
context?.closePDF()
}