Realize camera scanning QR code, photo album selects image recognition QR code
I. import framework
import AVFoundation//QR code scanning import CoreImage//QR code recognition import AudioToolbox//system sound
2, Compliance with agreement
AVCaptureMetadataOutputObjectsDelegate//Scan QR code CALayerDelegate// CALayer drawing UINavigationControllerDelegate//Picture selection controller UIImagePickerControllerDelegate
3, Code implementation
//Call camera
func setUpCamera() {
//Create device
guard let cameraDevice = AVCaptureDevice.default(for: .video) else {
print("Camera not supported")
return
}
//Create input, output stream
let deviceInput: AVCaptureInput
do{
deviceInput = try AVCaptureDeviceInput(device: cameraDevice)
}catch {
print("Camera not supported")
return
}
let deviceOutput = AVCaptureMetadataOutput()
deviceOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
//session settings
let session = AVCaptureSession()
//Collection quality
session.canSetSessionPreset(AVCaptureSession.Preset.high)
//Add input, output stream
if session.canAddInput(deviceInput) {
session.addInput(deviceInput)
}
if session.canAddOutput(deviceOutput) {
session.addOutput(deviceOutput)
}
//Barcode type AVMetadataObjectTypeQRCode, set the format supported by scanning
deviceOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.ean13,
AVMetadataObject.ObjectType.ean8,
AVMetadataObject.ObjectType.code128,
AVMetadataObject.ObjectType.qr]
//Set preview layer
let previewLayer = AVCaptureVideoPreviewLayer(session: session)
previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
previewLayer.frame = view.bounds
view.layer.insertSublayer(previewLayer, at: 0)
//Set the scanning area, or write your own calculation method
NotificationCenter.default.addObserver(forName: NSNotification.Name.AVCaptureInputPortFormatDescriptionDidChange, object: nil, queue: nil) { [weak self](noti) in
guard let strongSelf = self else { return }
deviceOutput.rectOfInterest = previewLayer.metadataOutputRectConverted(fromLayerRect: strongSelf.scanFrameView.frame)
}
//mask
let shadowLayer = CALayer()
shadowLayer.frame = view.bounds
shadowLayer.delegate = self
view.layer.insertSublayer(shadowLayer, above: previewLayer)
shadowLayer.setNeedsDisplay()
self.maskLayer = shadowLayer
self.session = session
}
//MARK: CALayerDelegate, create mask
func draw(_ layer: CALayer, in ctx: CGContext) {
if layer == maskLayer {
UIGraphicsBeginImageContextWithOptions((maskLayer?.frame.size)!, false, 1)
//Mask color
ctx.setFillColor(UIColor.RGBColor(r: 47, g: 47, b: 47, alpha: 0.6).cgColor)
ctx.fill((maskLayer?.frame)!)
let scanFrame = view.convert(scanFrameView.frame, from: scanFrameView.superview)
//Empty out the middle piece
ctx.clear(scanFrame)
}
}
//Scanline move
func scanAction() {
let startPoint = CGPoint(x: scanline.center.x, y: scanFrameView.frame.minY)
let endPoint = CGPoint(x: scanline.center.x, y: scanFrameView.frame.maxY)
let basicAnimation = CABasicAnimation(keyPath: "position")
basicAnimation.timingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.easeInEaseOut)
basicAnimation.fromValue = NSValue(cgPoint: startPoint)
basicAnimation.toValue = NSValue(cgPoint: endPoint)
basicAnimation.duration = 4
basicAnimation.repeatCount = MAXFLOAT
basicAnimation.autoreverses = false
scanline.layer.add(basicAnimation, forKey: nil)
}Be careful:
1. When the scanning area is not set, it defaults to the whole screen;
Set the rectOfInterest property of AVCaptureMetadataOutput when customizing the size. The rectOfInterest is of CGRect type, but its four values are different from the traditional one. They are (y, x, height, width) and proportional values, with a value range of 0 ~ 1.
There are two setting methods: (1) user defined method calculation (2) system method calculation, which should be put in the notice at this time, otherwise it will not work. Remember to remove the observer in the deinit method
//Custom method to calculate scan box size
func rectOfInterestByScanViewRect(rect:CGRect) -> CGRect{
let width = self.view.frame.size.width
let height = self.view.frame.size.height
let x = rect.minY / height
let y = rect.minX / width
let w = rect.size.height / height
let h = rect.size.width / width
return CGRect(x: x, y: y, width: w, height: h)
}//System method implementation
NotificationCenter.default.addObserver(forName: NSNotification.Name.AVCaptureInputPortFormatDescriptionDidChange, object: nil, queue: nil) { [weak self](noti) in
guard let strongSelf = self else { return }
deviceOutput.rectOfInterest = previewLayer.metadataOutputRectConverted(fromLayerRect: strongSelf.scanFrameView.frame)
}2. When creating the mask around the scan area, one method is to add UIView around the scan box, or create a layer like the one above, and then remove the range of the middle scan box
When using the layer, pay attention to obey the callyerdelegate protocol, set the agent, and finally setNeedsDisplay() will not execute without writing setNeedsDisplay()
Set delegate to nil in the deinit method, otherwise crash may occur
deinit {
maskLayer?.delegate = nil
NotificationCenter.default.removeObserver(self)
print("deinit ~ \(self)")
}Camera recognition
// MARK: - AVCaptureMetadataOutputObjectsDelegate
//Capture barcode proxy protocol
func metadataOutput(_ captureOutput: AVCaptureMetadataOutput, didOutput metadataObjects: [AVMetadataObject], from connection: AVCaptureConnection) {
if metadataObjects.count > 0 {
playSystemSound()
//Stop scanning
session?.stopRunning()
//Take the first QR code identified
let metadataobject = metadataObjects.first as? AVMetadataMachineReadableCodeObject
//Value of QR code
stringValue = metadataobject?.stringValue
//todoSomething.....
}
}
Album selection photo recognition
//MARK: UIImagePickerControllerDelegate
//Open local album
func openLocalPhoto() {
let imagePicker = UIImagePickerController()
imagePicker.sourceType = .photoLibrary
imagePicker.delegate = self
self.present(imagePicker, animated: true, completion: nil)
}
//Select finish
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
//The selected type is photo
let type = info[UIImagePickerController.InfoKey.mediaType] as! String
if type == "public.image" {
//Get photos
pickedImage = info[UIImagePickerController.InfoKey.originalImage] as? UIImage
print(pickedImage.size)
picker.dismiss(animated: true) {
self.scanQRCodeFromPhotoLibrary(image: self.pickedImage)
}
}
}
//Deselected
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
picker.dismiss(animated: true, completion: nil)
}
//Identify QR code
@objc func scanQRCodeFromPhotoLibrary(image: UIImage) {
guard let cgImage = image.cgImage else { return }
///Here, the accuracy of recognition is set to High, but this may take a little time.
if let detector = CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: [CIDetectorAccuracy: CIDetectorAccuracyHigh]) {
let features = detector.features(in: CIImage(cgImage: cgImage))
for feature in features { // In fact, two QR codes can be identified here, and only the first one (left or top) is taken here
if let qrFeature = feature as? CIQRCodeFeature {
playSystemSound()
session?.stopRunning()
//Get recognized string
stringValue = qrFeature.messageString
//to do something.....
return
}
}
}else {
//QR code not recognized
//to do something...
}
}
func playSystemSound() {
DispatchQueue.global().async {
//Play sound effects
let url = Bundle.main.url(forResource: "scanSuccess.wav", withExtension: nil)
var soundID: SystemSoundID = 8787
AudioServicesCreateSystemSoundID(url! as CFURL, &soundID)
AudioServicesPlaySystemSound(soundID)
}
}