Generate PDF from SwiftUI

Table of Contents

Why we need to convert a SwiftUI view into PDF?>

Why we need to convert a SwiftUI view into PDF? #

While working on one of my projects that involved generating content resembling a book page, I came across a requirement to share this page. But I faced a challenge: How could I share the content as a well-formatted document instead of just a string? I needed a solution that would allow me to generate a PDF.

What you need to implement>

What you need to implement #

Fortunately, after conducting extensive research, I stumbled upon a fantastic GitHub repository that had exactly what I was looking for: a perfect extension for SwiftUI views.

Extension>

Extension #

Extensions in Swift allow you to add methods to existing types, such as the View type in this case, to make them do things they weren’t originally designed to do. When implementing an extension, it’s a best practice to create a folder called “Extension” in your Xcode project and place the necessary files inside it.

Time to work>

Time to work #

Let’s start by creating a new Swift file in the Extension folder. I named mine ExportPDF.swift. Inside this file, you can paste the following code:

import SwiftUI

extension View{
    
    func sharePDF<Content: View> (@ViewBuilder content: @escaping () -> Content, fileName: String) {
        exportPDF(content: content, completion: { status , url in
            if let url = url, status {
                ShareSheet.instance.share(items: [url])
            } else {
                print("⚠️ Failed to make PDF")
            }
        }, fileName: fileName)
    }
    
    // MARK: Extracting View's Height and width with the Help of Hosting Controller and ScrollView
    fileprivate func convertToScrollView<Content: View>(@ViewBuilder content: @escaping ()->Content)->UIScrollView{
        
        let scrollView = UIScrollView()
        
        // MARK: Converting SwiftUI View to UIKit View
        let hostingController = UIHostingController(rootView: content()).view!
        hostingController.translatesAutoresizingMaskIntoConstraints = false
        
        // MARK: Constraints
        let constraints = [
        
            hostingController.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor),
            hostingController.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor),
            hostingController.topAnchor.constraint(equalTo: scrollView.topAnchor),
            hostingController.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor),
            
            // Width Anchor
            hostingController.widthAnchor.constraint(equalToConstant: screenBounds().width)
        ]
        scrollView.addSubview(hostingController)
        scrollView.addConstraints(constraints)
        scrollView.layoutIfNeeded()
        
        return scrollView
    }
    
    // MARK: Export to PDF
    // MARK: Completion Handler will Send Status and URL
    fileprivate func exportPDF<Content: View>(@ViewBuilder content: @escaping ()->Content,completion: @escaping (Bool,URL?)->(), fileName: String){
        
        // MARK: Temp URL
        let documentDirectory = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!
        // MARK: To Generate New File when ever its generated
        let outputFileURL = documentDirectory.appendingPathComponent("\(fileName)\(UUID().uuidString).pdf")
        
        // MARK: PDF View
        let pdfView = convertToScrollView {
            content()
        }
        pdfView.tag = 1009
        let size = pdfView.contentSize
        // Removing Safe Area Top Value
        pdfView.frame = CGRect(x: 0, y: getSafeArea().top, width: size.width, height: size.height)
        
        // MARK: Attaching to Root View and rendering the PDF
        getRootController().view.insertSubview(pdfView, at: 0)
        
        // MARK: Rendering PDF
        let renderer = UIGraphicsPDFRenderer(bounds: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        
        do{
            
            try renderer.writePDF(to: outputFileURL, withActions: { context in
                
                context.beginPage()
                pdfView.layer.render(in: context.cgContext)
            })
            
            completion(true,outputFileURL)
        }
        catch{
            completion(false,nil)
            print(error.localizedDescription)
        }
        
        // Removing the added View
        getRootController().view.subviews.forEach { view in
            if view.tag == 1009{
                print("Removed")
                view.removeFromSuperview()
            }
        }
    }
    
    fileprivate func screenBounds()->CGRect{
        return UIScreen.main.bounds
    }
    
    fileprivate func getRootController()->UIViewController{
        guard let screen = UIApplication.shared.connectedScenes.first as? UIWindowScene else{
            return .init()
        }
        
        guard let root = screen.windows.first?.rootViewController else{
            return .init()
        }
        
        return root
    }
    
    fileprivate func getSafeArea()->UIEdgeInsets{
        guard let screen = UIApplication.shared.connectedScenes.first as? UIWindowScene else{
            return .zero
        }
        
        guard let safeArea = screen.windows.first?.safeAreaInsets else{
            return .zero
        }
        
        return safeArea
    }
}

Share #

With the above extension, we can generate a PDF. However, we need to create another file to handle the sharing of the document. Create a new file, I called mine SharePDF.swift, and paste the following code:

import Foundation
import SwiftUI

struct ShareSheet {
    
    static let instance = ShareSheet()
    
    private init() { }
    
    func share(items: [Any]) {
        let controller = UIActivityViewController(activityItems: items, applicationActivities: nil)
        UIApplication.shared.currentUIWindow()?.rootViewController?.present(controller, animated: true, completion: nil)
    }
    
}

public extension UIApplication {
    func currentUIWindow() -> UIWindow? {
        let connectedScenes = UIApplication.shared.connectedScenes
            .filter({
                $0.activationState == .foregroundActive})
            .compactMap({$0 as? UIWindowScene})
        
        let window = connectedScenes.first?
            .windows
            .first { $0.isKeyWindow }

        return window
        
    }
}

Use the extension in a view>

Use the extension in a view #

The last step is to utilize what we have created in the view that you want to convert and share. To achieve this, add a button that triggers the sharing action. Here’s an example:

Button {
        sharePDF(content: { //THE VIEW THAT YOU WANT TO SHARE, FOR EXAMPLE USE self TO SHARE THE CURRENT VIEW }, fileName: //THE TITLE OF THE FILE YOU WANT GENERATE)
        } label: {
            Text("Share")
        }

Conclusion>

Conclusion #

With this implementation, you will be able to generate PDFs of your views and share them with just one tap. If you encounter any issues with the provided code, you can refer to the repository link I found, which inspired this solution.