Building a Custom PDF Generator in SwiftUI (Export & Share PDFs)

 

Generating PDFs is a common requirement in modern iOS apps, whether it’s for invoices, reports, or certificates. SwiftUI, combined with UIKitcapabilities, makes it easy to create, export, and share PDFs seamlessly.

In this guide, we’ll cover:

✅ Generating a PDF from SwiftUI views
✅ Exporting and saving the PDF file
✅ Sharing the generated PDF using the Share Sheet
✅ Adding custom styling & layouts to the PDF

🔹 Step 1: Creating a PDF from SwiftUI View

SwiftUI doesn’t have a built-in PDF generator, so we’ll use UIGraphicsPDFRenderer from UIKit. We’ll first create a function that converts a SwiftUI view into a UIImage and then render it as a PDF.

Helper Function: Convert SwiftUI View to UIImage

import SwiftUI

extension View {
    func snapshot() -> UIImage {
        let controller = UIHostingController(rootView: self)
        let view = controller.view
        let targetSize = view?.intrinsicContentSize ?? CGSize(width: 300, height: 400)
        view?.bounds = CGRect(origin: .zero, size: targetSize)
        view?.backgroundColor = .clear
        
        let renderer = UIGraphicsImageRenderer(size: targetSize)
        return renderer.image { _ in
            view?.drawHierarchy(in: view!.bounds, afterScreenUpdates: true)
        }
    }
}

This function captures any SwiftUI view as an image, which we can then use for generating PDFs.

🔹 Step 2: Generating the PDF File

We will now create a function to render the captured image as a PDF.

import UIKit

func generatePDF(from image: UIImage) -> URL? {
    let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: image.size))
    let url = FileManager.default.temporaryDirectory.appendingPathComponent("GeneratedPDF.pdf")
    
    do {
        try pdfRenderer.writePDF(to: url, withActions: { context in
            context.beginPage()
            image.draw(in: CGRect(origin: .zero, size: image.size))
        })
        return url
    } catch {
        print("Error generating PDF: \(error.localizedDescription)")
        return nil
    }
}

This function:

• Takes a UIImage and converts it into a PDF.
• Saves the PDF in the temporary directory.

🔹 Step 3: Sharing the PDF

Once we generate the PDF, we can allow users to share it using SwiftUI’s ShareSheet.

import UIKit
import SwiftUI

struct ShareSheet: UIViewControllerRepresentable {
    let activityItems: [Any]
    
    func makeUIViewController(context: Context) -> UIActivityViewController {
        return UIActivityViewController(activityItems: activityItems, applicationActivities: nil)
    }
    
    func updateUIViewController(_ uiViewController: UIActivityViewController, context: Context) {}
}

Using the ShareSheet in SwiftUI

struct ContentView: View {
    @State private var showShareSheet = false
    @State private var pdfURL: URL?
    
    var body: some View {
        VStack {
            Text("Hello, SwiftUI PDF!")
                .font(.title)
                .padding()
                .background(Color.yellow.cornerRadius(10))
                .padding()
                
            Button("Generate & Share PDF") {
                let image = Text("SwiftUI PDF Example").snapshot()
                pdfURL = generatePDF(from: image)
                showShareSheet = true
            }
            .padding()
            .background(Color.blue.cornerRadius(10))
            .foregroundColor(.white)
        }
        .sheet(isPresented: $showShareSheet) {
            if let pdfURL = pdfURL {
                ShareSheet(activityItems: [pdfURL])
            }
        }
    }
}

This will generate a PDF of the SwiftUI text and allow the user to share it.

🎯 Final Thoughts

✅ SwiftUI can easily generate and share PDFs using UIViewControllerRepresentable.
✅ You can capture SwiftUI views as images and render them into a PDF format.
✅ Enhance your app with features like multi-page PDFs, text formatting, and images.

Now you can generate, export, and share PDFs effortlessly in SwiftUI! 🚀