将 uiimageview 转换为 pdf - Swift [英] Converting uiimageview to pdf - Swift

问题描述

我正在尝试使用 swift 创建一个 iOS 应用程序，该应用程序允许用户拍照或从他们的图库中选择一张图片，并将其转换为他们能够保存到手机中的 pdf 文件.我的代码目前可以打开相机或图库并选择图像，但我无法将其转换为 pdf.任何提示将不胜感激，谢谢！

I am trying to create an iOS app using swift that will let the user either take a photo or choose an image from their gallery, and convert it to a pdf file that they are able to save to their phone. My code currently works to open either the camera or the gallery and choose an image, but I'm unable to convert it to pdf. Any tips would be really appreciated, thanks!

CameraViewController 类

CameraViewController class

import UIKit

class CameraViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate
 {

    @IBOutlet weak var myImg: UIImageView!

    @IBAction func takePhoto(_ sender: AnyObject) {
        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera) {
            let imagePicker = UIImagePickerController()
            imagePicker.delegate = self
            imagePicker.sourceType = UIImagePickerControllerSourceType.camera
            imagePicker.allowsEditing = false
            self.present(imagePicker, animated: true, completion: nil)
        }
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            myImg.contentMode = .scaleToFill
            myImg.image = pickedImage
        }
        picker.dismiss(animated: true, completion: nil)
    }

    @IBAction func savePhoto(_ sender: AnyObject) {
        let imageData = UIImagePNGRepresentation(myImg.image!)
        let compressedImage = UIImage(data: imageData!)
        UIImageWriteToSavedPhotosAlbum(compressedImage!, nil, nil, nil)

        let alert = UIAlertController(title: "Saved", message: "Your image has been saved", preferredStyle: .alert)
        let okAction = UIAlertAction(title: "Ok", style: .default, handler: nil)
        alert.addAction(okAction)
        self.present(alert, animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

GalleryViewController 类

GalleryViewController class

import UIKit

class GalleryViewController: UIViewController {

    @IBOutlet weak var myImg: UIImageView!

    @IBAction func pickPhoto(_ sender: Any) {
        if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.photoLibrary) {
            let imagePicker = UIImagePickerController()
            imagePicker.delegate = self as? UIImagePickerControllerDelegate & UINavigationControllerDelegate
            imagePicker.sourceType = UIImagePickerControllerSourceType.photoLibrary
            imagePicker.allowsEditing = true
            self.present(imagePicker, animated: true, completion: nil)
        }
    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            myImg.contentMode = .scaleToFill
            myImg.image = pickedImage
        }
        picker.dismiss(animated: true, completion: nil)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

推荐答案

答案更新:

由于Apple将PDFKit引入iOS 11.0，您可以使用下面的代码将uiimage转换为pdf，我只尝试了下面的osx，但它应该在iOS上以同样的方式工作.

Since Apple introduced PDFKit to iOS 11.0, you can use the code below to convert uiimage to pdf, I only tried the osx below, but it should work the same way on iOS.

// Create an empty PDF document
let pdfDocument = PDFDocument()

// Load or create your UIImage
let image = UIImage(....)

// Create a PDF page instance from your image
let pdfPage = PDFPage(image: image!)

// Insert the PDF page into your document
pdfDocument.insert(pdfPage!, at: 0)

// Get the raw data of your PDF document
let data = pdfDocument.dataRepresentation()

// The url to save the data to
let url = URL(fileURLWithPath: "/Path/To/Your/PDF")

// Save the data to the url
try! data!.write(to: url)

=================================================

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实际上有很多类似的问题和足够好的答案.让我再试着回答一下.

Actually there're a lot similar questions and good enough answers. Let me try to answer this again.

生成PDF基本上和iOS中的绘图类似.

Basically generating PDF is similar to the drawing in iOS.

1. 创建 PDF 上下文并将其推送到图形堆栈.
2. 创建一个页面.
3. 使用 UIKit 或 Core Graphics 例程来绘制页面内容.
4. 根据需要添加链接.
5. 根据需要重复第 2、3 和 4 步.
6. 结束 PDF 上下文以从图形堆栈中弹出上下文，并根据上下文的创建方式将结果数据写入指定的 PDF 文件或将其存储到指定的 NSMutableData 对象中.

所以最简单的方法是这样的:

So the most simple way would be something like this:

func createPDF(image: UIImage) -> NSData? {

    let pdfData = NSMutableData()
    let pdfConsumer = CGDataConsumer(data: pdfData as CFMutableData)!

    var mediaBox = CGRect.init(x: 0, y: 0, width: image.size.width, height: image.size.height)

    let pdfContext = CGContext(consumer: pdfConsumer, mediaBox: &mediaBox, nil)!

    pdfContext.beginPage(mediaBox: &mediaBox)
    pdfContext.draw(image.cgImage!, in: mediaBox)
    pdfContext.endPage()

    return pdfData
}

为PDF文件创建了所有的NSData，然后我们需要将数据保存到文件中:

That created all the NSData for the PDF file, then we need to save the data to file:

let documentDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
let docURL = documentDirectory.appendingPathComponent("myFileName.pdf")

try createPDF(image: someUIImageFile)?.write(to: docURL, atomically: true)

在此处阅读更多信息:生成 PDF 内容

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