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
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()
}
I loved this answer, but couldn't get it to work. I was getting an exception and the catch wasn't being executed.
After some head scratching, and writing up a SO Question asking how to debug it (which I never submitted), I realized that the solution, while not obvious, was simple: wrap the rendering phase in an async call to the main queue:
//Render the PDF
let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(x: 0, y: 0, width: 8.5 * 72.0, height: height))
DispatchQueue.main.async {
do {
try pdfRenderer.writePDF(to: outputFileURL, withActions: { (context) in
context.beginPage()
pdfVC.view.layer.render(in: context.cgContext)
})
print("wrote file to: \(outputFileURL.path)")
} catch {
print("Could not create PDF file: \(error.localizedDescription)")
}
}
Thanks, SnOwfreeze!
I tried all the answers, but they didn't work for me (Xcode 12.4, iOS 14.4). Here is what's worked for me:
import SwiftUI
func exportToPDF() {
let outputFileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("SwiftUI.pdf")
let pageSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
//View to render on PDF
let myUIHostingController = UIHostingController(rootView: ContentView())
myUIHostingController.view.frame = CGRect(origin: .zero, size: pageSize)
//Render the view behind all other views
guard let rootVC = UIApplication.shared.windows.first?.rootViewController else {
print("ERROR: Could not find root ViewController.")
return
}
rootVC.addChild(myUIHostingController)
//at: 0 -> draws behind all other views
//at: UIApplication.shared.windows.count -> draw in front
rootVC.view.insertSubview(myUIHostingController.view, at: 0)
//Render the PDF
let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))
DispatchQueue.main.async {
do {
try pdfRenderer.writePDF(to: outputFileURL, withActions: { (context) in
context.beginPage()
myUIHostingController.view.layer.render(in: context.cgContext)
})
print("wrote file to: \(outputFileURL.path)")
} catch {
print("Could not create PDF file: \(error.localizedDescription)")
}
//Remove rendered view
myUIHostingController.removeFromParent()
myUIHostingController.view.removeFromSuperview()
}
}
Note: Don't try to use this function in a view with .onAppear when you try to export the same view. This will result in a endless loop naturally.
When I tried to generate a PDF file using the the solutions in other answers I only got a blurred PDF and the quality was far from good.
I ended up generating the SwiftUI view in a much bigger frame and scaled down the context to the appropriate size.
Here are my modifications to the Sn0wfreeze's answer:
// scale 1 -> 72 DPI
// scale 4 -> 288 DPI
// scale 300 / 72 -> 300 DPI
let dpiScale: CGFloat = 4
// for US letter page size
let pageSize = CGSize(width: 8.5 * 72, height: 11 * 72)
// for A4 page size
// let pageSize = CGSize(width: 8.27 * 72, height: 11.69 * 72)
let pdfVC = UIHostingController(rootView: swiftUIview)
pdfVC.view.frame = CGRect(origin: .zero, size: pageSize * dpiScale)
...
let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))
do {
try pdfRenderer.writePDF(to: outputFileURL) { context in
context.beginPage()
context.cgContext.scaleBy(x: 1 / dpiScale, y: 1 / dpiScale)
pdfVC.view.layer.render(in: context.cgContext)
}
print("File saved to: \(outputFileURL.path)")
}
...
I also used the following extension to multiply CGSize by CGFloat:
extension CGSize {
static func * (size: CGSize, value: CGFloat) -> CGSize {
return CGSize(width: size.width * value, height: size.height * value)
}
}
I tried the other methods above but still had issues with the view showing properly, so here is what I have that works for me on Xcode 12.2 & Swift 5 after messing with both Sn0wfreeze's Answer & pawello2222's Answer:
func exportToPDF() {
let outputFileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent("SwiftUI.pdf")
let pageSize = CGSize(width: UIScreen.main.bounds.width, height: UIScreen.main.bounds.height)
let rootVC = UIApplication.shared.windows.first?.rootViewController
//Render the PDF
let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))
DispatchQueue.main.async {
do {
try pdfRenderer.writePDF(to: outputFileURL, withActions: { (context) in
context.beginPage()
rootVC?.view.layer.render(in: context.cgContext)
})
print("wrote file to: \(outputFileURL.path)")
} catch {
print("Could not create PDF file: \(error.localizedDescription)")
}
}
}
Basically, I removed any reference to a newly created "pdfVC" view controller, and only referenced the main view the entire time as our "rootVC". I grab the screen width and height and use that to define our PDF's width and height, rather than trying to scale the view to proper A4 or letter size. This creates a PDF of the entire showing SwiftUI view.
Hope this helps anyone that had any issues with the other answers! :)
func exportToPDF() {
let listHeight: CGFloat = 24.0//or you can get it from your ListView
let rowsCount = yourArrayOrObject.count
let rowsCountPerPage = Int(11.69 * 72 / listHeight) - 6
let countOfPages = Int(ceil( Double(rowsCount) / Double(rowsCountPerPage)))
var index = 0
while index < countOfPages {
let items = yourArrayOrObject.slice(size: rowsCountPerPage)[index]
let rootView = List {
ForEach(items, id: \.self) { item in
Text("\(item.name)")
}
}
let dpiScale: CGFloat = 1.5
// for US letter page size
// let pageSize = CGSize(width: 8.5 * 72, height: 11 * 72)
// for A4 page size
let pageSize = CGSize(width: 8.27 * 72, height: 11.69 * 72)
//View to render on PDF
let myUIHostingController = UIHostingController(rootView: rootView)
myUIHostingController.view.frame = CGRect(origin: .zero, size: pageSize * dpiScale)
myUIHostingController.view.overrideUserInterfaceStyle = .light//it will be light, when dark mode
//Render the view behind all other views
guard let rootVC = UIApplication.shared.windows.first?.rootViewController else {
print("ERROR: Could not find root ViewController.")
return
}
rootVC.addChild(myUIHostingController)
//at: 0 -> draws behind all other views
//at: UIApplication.shared.windows.count -> draw in front
rootVC.view.insertSubview(myUIHostingController.view, at: 0)
//Render the PDF
let pdfRenderer = UIGraphicsPDFRenderer(bounds: CGRect(origin: .zero, size: pageSize))
let data = pdfRenderer.pdfData { context in
context.beginPage()
context.cgContext.scaleBy(x: 1 / dpiScale, y: 1 / dpiScale)
myUIHostingController.view.layer.render(in: context.cgContext)
}
//Remove rendered view
myUIHostingController.removeFromParent()
myUIHostingController.view.removeFromSuperview()
if index == 0 {
pdfDocumentData = data // pdfDocumentData must be declared above: @State private var pdfDocumentData = Data()(don't forget import PDFKit)
} else {
pdfDocumentData = mergePdf(data: pdfDocumentData, otherPdfDocumentData: data).dataRepresentation()!
}
index += 1
}
writeDataToTemporaryDirectory(withFilename: "YourPDFFileName.pdf", data: pdfDocumentData)
}
private func writeDataToTemporaryDirectory(withFilename: String, data: Data) {
do {
// name the file
let temporaryFileURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!.appendingPathComponent(withFilename)
print("writeDataToTemporaryDirectory at url:\t\(temporaryFileURL)")
try data.write(to: temporaryFileURL, options: .atomic)
print("It's Ok!")//you can open file in sheet: (self.showReport = true) ,for example
pdfDocumentData = Data()
} catch {
print(error)
}
}
func mergePdf(data: Data, otherPdfDocumentData: Data) -> PDFDocument {
// get the pdfData
let pdfDocument = PDFDocument(data: data)!
let otherPdfDocument = PDFDocument(data: otherPdfDocumentData)!
// create new PDFDocument
let newPdfDocument = PDFDocument()
// insert all pages of first document
for p in 0..<pdfDocument.pageCount {
let page = pdfDocument.page(at: p)!
newPdfDocument.insert(page, at: newPdfDocument.pageCount)
}
// insert all pages of other document
for q in 0..<otherPdfDocument.pageCount {
let page = otherPdfDocument.page(at: q)!
newPdfDocument.insert(page, at: newPdfDocument.pageCount)
}
return newPdfDocument
}
Works for XCode 13, iOS 15, It's multi pages solution
pdfDocumentData must be declared above: @State private var pdfDocumentData = Data() (don't forget import PDFKit) Thanks pawello2222
here are some required extensions
extension CGSize {
static func * (size: CGSize, value: CGFloat) -> CGSize {
return CGSize(width: size.width * value, height: size.height * value)
}
}
extension Array {
func slice(size: Int) -> [[Element]] {
(0...(count / size)).map{Array(self[($0 * size)..<(Swift.min($0 * size + size, count))])}
}
}