Convert SwiftUI View to PDF on iOS

Question

I was drawing some nice graphs with SwiftUI, because it is so simple and easy to do. Then I wanted to export the whole SwiftUI View to a PDF such that someone else can view the graphs in a nice way. SwiftUI does not offer a solution for this directly.

Cheers,
Alex

Answer 1

After some thinking I came up with the idea of combining the UIKit to PDF method and SwiftUI.

At first you create your SwiftUI view, then you put into an UIHostingController. You render the HostingController on a window behind all other views and and draw its layer on a PDF. Sample code is listed below.

func exportToPDF() {

    let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let outputFileURL = documentDirectory.appendingPathComponent("SwiftUI.pdf")

    //Normal with
    let width: CGFloat = 8.5 * 72.0
    //Estimate the height of your view
    let height: CGFloat = 1000
    let charts = ChartsView()

    let pdfVC = UIHostingController(rootView: charts)
    pdfVC.view.frame = CGRect(x: 0, y: 0, width: width, height: height)

    //Render the view behind all other views
    let rootVC = UIApplication.shared.windows.first?.rootViewController
    rootVC?.addChild(pdfVC)
    rootVC?.view.insertSubview(pdfVC.view, at: 0)

    //Render the PDF
    let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(x: 0, y: 0, width: 8.5 * 72.0, height: height))

    do {
        try pdfRenderer.writePDF(to: outputFileURL, withActions: { (context) in
            context.beginPage()
            pdfVC.view.layer.render(in: context.cgContext)
        })

        self.exportURL = outputFileURL
        self.showExportSheet = true

    }catch {
        self.showError = true
        print("Could not create PDF file: \(error)")
    }

    pdfVC.removeFromParent()
    pdfVC.view.removeFromSuperview()
}