[Student] Allow Document Scan to Fallback to PDFs

Core/Core/Common/Extensions/PDFKit/PDFDocumentExtensions.swift

@@ -0,0 +1,39 @@
+//
+// This file is part of Canvas.
+// Copyright (C) 2025-present  Instructure, Inc.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+import PDFKit
+
+extension PDFDocument {
+
+    @discardableResult
+    public func write(to url: URL? = nil, name: String? = nil) throws -> URL {
+        let directory = url ?? URL.Directories.temporary.appendingPathComponent("Documents", isDirectory: true)
+        let name = name ?? String(Clock.now.timeIntervalSince1970)
+        try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true, attributes: nil)
+        var url = directory.appendingPathComponent(name, isDirectory: false)
+        url = url.pathExtension != "pdf" ? url.appendingPathExtension("pdf") : url
+        guard let data = dataRepresentation() else {
+            throw NSError.instructureError(String(localized: "Failed to save pdf", bundle: .core))
+        }
+        if FileManager.default.fileExists(atPath: url.path) {
+            try FileManager.default.removeItem(at: url)
+        }
+        try data.write(to: url)
+        return url
+    }
+}

Core/Core/Features/Files/Model/Entities/UTI.swift

@@ -131,6 +131,9 @@ public struct UTI: Equatable, Hashable {
     public var isImage: Bool {
         return uttype?.conforms(to: .image) ?? false
     }
+    public var isPdf: Bool {
+        return uttype?.conforms(to: .pdf) ?? false
+    }
 
     public var isAudio: Bool {
         return uttype?.conforms(to: .audio) ?? false

Core/Core/Features/Files/View/FilePicker/FilePickerViewController.swift

@@ -20,6 +20,7 @@ import Combine
 import UIKit
 import MobileCoreServices
 import VisionKit
+import PDFKit
 import UniformTypeIdentifiers
 
 public enum FilePickerSource: Int, CaseIterable {
@@ -377,13 +378,29 @@ extension FilePickerViewController: UITableViewDelegate, UITableViewDataSource {
 extension FilePickerViewController: VNDocumentCameraViewControllerDelegate {
     public func documentCameraViewController(_ controller: VNDocumentCameraViewController, didFinishWith scan: VNDocumentCameraScan) {
         controller.dismiss(animated: true)
-        for i in 0..<scan.pageCount {
+
+        let usePdf = utis.contains(where: { $0.isPdf }) && !utis.contains(where: { $0.isImage })
+
+        if usePdf {
+            let pdfDocument = PDFDocument()
+
+            let pages = (0 ..< scan.pageCount).compactMap { PDFPage(image: scan.imageOfPage(at: $0)) }
+            pages.forEach { pdfDocument.insert($0, at: pdfDocument.pageCount) }
+
             do {
-                let image = scan.imageOfPage(at: i)
-                add(try image.write())
+                add(try pdfDocument.write())
             } catch {
                 showError(error)
             }
+        } else {
+            for i in 0..<scan.pageCount {
+                do {
+                    let image = scan.imageOfPage(at: i)
+                    add(try image.write())
+                } catch {
+                    showError(error)
+                }
+            }
         }
     }
 }

Student/Student/Submissions/SubmissionButton/SubmissionButtonPresenter.swift

@@ -231,6 +231,8 @@ extension SubmissionButtonPresenter: FilePickerControllerDelegate {
         if assignment.allowedExtensions.isEmpty == true || allowedUTIs.contains(where: { $0.isImage || $0.isVideo }) {
             filePicker.sources.append(contentsOf: [.library, .camera])
             if !isMediaRecording { filePicker.sources.append(.documentScan) }
+        } else if allowedUTIs.contains(where: { $0.isPdf }) {
+            filePicker.sources.append(.documentScan)
         }
         if isMediaRecording { filePicker.sources.append(.audio) }
         filePicker.utis = allowedUTIs