Program to generate QRCode and email it as attachment not working because UIImagePNGRepresentation is giving back nil

Question

Program to generate QRCode and email it as attachment not working because UIImagePNGRepresentation is giving back nil

119 Views Asked by user9832689 At 20 October 2024 at 03:46

Please find code below.

I am creating a QRCode.
Then I want to convert it to png and email as an attachment.

The line:

let imgData = UIImagePNGRepresentation(imageToEmail)

keeps giving back nil and causes the code to crash. Any help?

class ViewController: UIViewController, MFMailComposeViewControllerDelegate {
    @IBOutlet weak var dataField: UITextField!
    @IBOutlet weak var displayCodeView: UIImageView!

    var filter:CIFilter!
    var qrImage = UIImage()

    @IBAction func generatePressed(_ sender: UIButton) {
        if let text = dataField.text {
            let data = text.data(using: .ascii, allowLossyConversion: false)

            filter = CIFilter(name: "CIQRCodeGenerator")
            filter.setValue(data, forKey: "inputMessage")

            let transform = CGAffineTransform(scaleX: 10, y: 10)

            qrImage = UIImage(ciImage: filter.outputImage!.transformed(by: transform))
            displayCodeView.image = qrImage

            let mailComposeViewController = configureMailController(imageToEmail: qrImage)
            if MFMailComposeViewController.canSendMail() {
                self.present(mailComposeViewController, animated: true, completion: nil)
            } else {
                showMailError()
            }
        }
    }

    func configureMailController(imageToEmail: UIImage) -> MFMailComposeViewController {
        let mailComposerVC = MFMailComposeViewController()
        mailComposerVC.mailComposeDelegate = self

        mailComposerVC.setToRecipients(["[email protected]"])
        mailComposerVC.setSubject("QRCode")
        let imgData = UIImagePNGRepresentation(imageToEmail)
        mailComposerVC.addAttachmentData(imgData!, mimeType: "image/png", fileName:  "qrCode.png")
        let emailBody = "<html><body><p>QR code is attached in image </p></body></html>"
        mailComposerVC.setMessageBody(emailBody, isHTML:true)

        return mailComposerVC
    }

    func showMailError() {
        let sendMailErrorAlert = UIAlertController(title: "Email error", message: "Your device could not send email", preferredStyle: .alert)
        let dismiss = UIAlertAction(title: "Ok", style: .default, handler: nil)
        sendMailErrorAlert.addAction(dismiss)
        self.present(sendMailErrorAlert, animated: true, completion: nil)
    }

    func mailComposeController(_ controller: MFMailComposeViewController, didFinishWith result: MFMailComposeResult, error: Error?) {
        switch result {
        case .cancelled:
            print("Mail cancelled")
            break
        case .saved:
            print("Mail saved")
            break
        case .sent:
            print("Mail sent")
            break
        case .failed:
            print("Mail failed to send")
            break

        }
        controller.dismiss(animated: true, completion: nil)
    }
}

Original Q&A

There are 1 best solutions below

**AudioBubble** · Accepted Answer

Add this extension to your code

extension UIImage {

/**
 Creates the UIImageJPEGRepresentation out of an UIImage
 @return Data
 */

func generatePNGRepresentation() -> Data? {

    let newImage = self.copyOriginalImage()
    let newData = UIImagePNGRepresentation(newImage)

    return newData!
}

/**
 Copies Original Image which fixes the crash for extracting Data from UIImage
 @return UIImage
 */

private func copyOriginalImage() -> UIImage {
    UIGraphicsBeginImageContext(self.size);
    self.draw(in: CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height))
    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext();

    return newImage!
    }
}

In your code,

let imgData = imageToEmail.generatePNGRepresentation()

Program to generate QRCode and email it as attachment not working because UIImagePNGRepresentation is giving back nil

There are 1 best solutions below

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