iOS开发：使用PDFKit从相机拍摄图片生成PDF及相关问题咨询

Hey there! As someone who’s worked with PDFKit and iOS image handling a fair bit, let’s walk through your questions step by step to get you sorted.

When you take a photo via UIImagePickerController, the system generates a default filename for the image, but it’s not directly available in the info dictionary. Instead, we can use the Photos framework to fetch this name through a PHAsset:

• First, make sure you’ve added the Photos framework to your project, and added NSPhotoLibraryUsageDescription to your Info.plist (you need this permission to access album assets).
• In your imagePickerController(_:didFinishPickingMediaWithInfo:) method, retrieve the PHAsset from the info dict and fetch the filename:

import Photos

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
    picker.dismiss(animated: true)
    
    // Fetch the PHAsset associated with the photo
    if let asset = info[.phAsset] as? PHAsset {
        PHImageManager.default().requestImageDataAndOrientation(for: asset, options: nil) { data, _, _, infoDict in
            // Extract the file name from the returned info dictionary
            if let fileURL = infoDict?["PHImageFileURLKey"] as? URL {
                let imageName = fileURL.lastPathComponent
                print("Image filename: \(imageName)")
                // Use this name for your PDF conversion logic
            }
        }
    }
    
    // Your existing code to save the image to the album...
}

If you don’t need the system-generated filename, you can also create a custom one (like using a timestamp) for simplicity:

let customImageName = "captured_photo_\(Date().timeIntervalSince1970).jpg"

Absolutely! PDFKit has all the tools you need to create a PDF where users can move, scale, or delete images. Here’s a high-level approach:

Step 1: Create a PDF with your image #

First, convert your UIImage into a PDFPage and add it to a PDFDocument:

import PDFKit

func createPDFWithImage(_ image: UIImage) -> PDFDocument {
    let pdfDoc = PDFDocument()
    guard let pdfPage = PDFPage(image: image) else { return pdfDoc }
    pdfDoc.insert(pdfPage, at: 0)
    return pdfDoc
}

Step 2: Add images as editable annotations #

To make images interactive, wrap them in PDFAnnotation (this makes it easier to handle gestures for editing):

func addEditableImage(to pdfPage: PDFPage, image: UIImage, at position: CGPoint) {
    let imageBounds = CGRect(origin: position, size: image.size)
    let imageAnnotation = PDFAnnotation(bounds: imageBounds, forType: .stamp, withProperties: nil)
    imageAnnotation.image = image
    imageAnnotation.shouldDisplay = true
    pdfPage.addAnnotation(imageAnnotation)
}

Step 3: Add gesture recognizers for editing #

Add pan, pinch, and long-press gestures to your PDFView to handle moving, scaling, and deleting annotations:

// Add gestures to your PDFView in viewDidLoad()
override func viewDidLoad() {
    super.viewDidLoad()
    let panGesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
    let pinchGesture = UIPinchGestureRecognizer(target: self, action: #selector(handlePinch(_:)))
    let longPressGesture = UILongPressGestureRecognizer(target: self, action: #selector(handleLongPress(_:)))
    
    pdfView.addGestureRecognizer(panGesture)
    pdfView.addGestureRecognizer(pinchGesture)
    pdfView.addGestureRecognizer(longPressGesture)
}

// Handle pan to move the selected annotation
@objc func handlePan(_ gesture: UIPanGestureRecognizer) {
    guard let pdfView = gesture.view as? PDFView,
          let selectedAnnotation = pdfView.currentSelection?.annotations.first as? PDFAnnotation,
          gesture.state == .changed else { return }
    
    let translation = gesture.translation(in: pdfView)
    selectedAnnotation.bounds = selectedAnnotation.bounds.offsetBy(dx: translation.x, dy: translation.y)
    gesture.setTranslation(.zero, in: pdfView)
}

// Handle pinch to scale the selected annotation
@objc func handlePinch(_ gesture: UIPinchGestureRecognizer) {
    guard let pdfView = gesture.view as? PDFView,
          let selectedAnnotation = pdfView.currentSelection?.annotations.first as? PDFAnnotation,
          gesture.state == .changed else { return }
    
    let scale = gesture.scale
    selectedAnnotation.bounds = selectedAnnotation.bounds.applying(CGAffineTransform(scaleX: scale, y: scale))
    gesture.scale = 1.0
}

// Handle long press to delete the annotation
@objc func handleLongPress(_ gesture: UILongPressGestureRecognizer) {
    guard let pdfView = gesture.view as? PDFView,
          let selectedAnnotation = pdfView.currentSelection?.annotations.first,
          gesture.state == .began else { return }
    
    let alert = UIAlertController(title: "Delete Image?", message: "Remove this image from the PDF?", preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "Delete", style: .destructive) { _ in
        selectedAnnotation.page?.removeAnnotation(selectedAnnotation)
    })
    alert.addAction(UIAlertAction(title: "Cancel", style: .cancel))
    present(alert, animated: true)
}

Step 4: Save the edited PDF #

Once the user is done editing, save the PDF to the document directory:

func saveEditedPDF(_ document: PDFDocument) {
    let docsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
    let saveURL = docsDir.appendingPathComponent("edited_pdf.pdf")
    document.write(to: saveURL)
    // You can then share this URL or save it to the user's files
}

Here’s a clean version of the image picker code you referenced:

import UIKit
import Photos

class PhotoCaptureViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Set up your UI (e.g., a "Take Photo" button) here
    }

    @IBAction func takePhotoButtonTapped(_ sender: UIButton) {
        guard UIImagePickerController.isSourceTypeAvailable(.camera) else {
            print("Camera not available on this device")
            return
        }
        
        let imagePicker = UIImagePickerController()
        imagePicker.sourceType = .camera
        imagePicker.delegate = self
        imagePicker.allowsEditing = false // Set to true if you want post-capture editing
        present(imagePicker, animated: true)
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        picker.dismiss(animated: true)
        
        guard let capturedImage = info[.originalImage] as? UIImage else {
            print("Failed to retrieve captured image")
            return
        }
        
        // Save image to photo album
        UIImageWriteToSavedPhotosAlbum(capturedImage, self, #selector(imageSaveCompletion(_:didFinishSavingWithError:contextInfo:)), nil)
        
        // Here you can call your PDF creation/editing methods
        let pdfDoc = createPDFWithImage(capturedImage)
        pdfView.document = pdfDoc
    }

    @objc func imageSaveCompletion(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) {
        if let error = error {
            print("Error saving image: \(error.localizedDescription)")
        } else {
            print("Image saved to photo album successfully")
        }
    }

    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true)
    }
}

内容的提问来源于stack exchange，提问作者neda Derakhshesh