how to edit a PDF in objective-c?

Question

i\'m writing an application in objective-c (using cocoa). i have a PDF template, i need to substitute actual values into placeholders in PDF and then save the result into ne

Answer 1

I know that the question is about obj-c, but if you are here because of the edit pdf, below there is a solution in Swift 3:

PS: In my solution I needed to edit the document info of the new PDF, so I used the subject parameter to do this.

func createPDF(on path: String?, from templateURL: URL?, with subject: String?) {
    guard let newPDFPath = path,
        let pdfURL = templateURL else { return }

    let options = [(kCGPDFContextSubject as String): subject ?? ""] as CFDictionary

    UIGraphicsBeginPDFContextToFile(newPDFPath, .zero, options as? [AnyHashable : Any])

    let templateDocument = CGPDFDocument(pdfURL as CFURL)
    let pageCount = templateDocument?.numberOfPages ?? 0

    for i in 1...pageCount {

        //get bounds of template page
        if let templatePage = templateDocument?.page(at: i) {
            let templatePageBounds = templatePage.getBoxRect(.cropBox)

            //create empty page with corresponding bounds in new document
            UIGraphicsBeginPDFPageWithInfo(templatePageBounds, nil)
            let context = UIGraphicsGetCurrentContext()

            //flip context due to different origins
            context?.translateBy(x: 0.0, y: templatePageBounds.height)
            context?.scaleBy(x: 1.0, y: -1.0)

            //copy content of template page on the corresponding page in new file
            context?.drawPDFPage(templatePage)

            //flip context back
            context?.translateBy(x: 0.0, y: templatePageBounds.height)
            context?.scaleBy(x: 1.0, y: -1.0)
        }
    }
    UIGraphicsEndPDFContext()
}