我目前正在为我的Swift应用程序开发QR扫描视图。我想将VideoPreview居中在我的视图中间。
视图如下所示: 该视图(白色)称为ScanView,我想使图像预览与ScanView大小相同,并将其居中。
代码片段: 感谢您的帮助!
视图如下所示: 该视图(白色)称为ScanView,我想使图像预览与ScanView大小相同,并将其居中。
代码片段: 感谢您的帮助!
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureVideoDataOutputSampleBufferDelegate, AVCaptureMetadataOutputObjectsDelegate {
@IBOutlet weak var innerView: UIView!
var session: AVCaptureSession?
var input: AVCaptureDeviceInput?
var previewLayer: AVCaptureVideoPreviewLayer?
override func viewDidLoad() {
super.viewDidLoad()
createSession()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
self.previewLayer?.frame.size = self.innerView.frame.size
}
private func createSession() {
do {
self.session = AVCaptureSession()
if let device = AVCaptureDevice.default(for: AVMediaType.video) {
self.input = try AVCaptureDeviceInput(device: device)
self.session?.addInput(self.input!)
self.previewLayer = AVCaptureVideoPreviewLayer(session: self.session!)
self.previewLayer?.frame.size = self.innerView.frame.size
self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
self.innerView.layer.addSublayer(self.previewLayer!)
//______ 1. solution with Video camera ______//
let videoOutput = AVCaptureVideoDataOutput()
videoOutput.setSampleBufferDelegate(self, queue: DispatchQueue.main)
self.session?.canAddOutput(videoOutput)
self.session?.addOutput(videoOutput)
self.session?.startRunning()
//______ 2. solution with QR code ______//
let videoOutput = AVCaptureMetadataOutput()
videoOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
self.session?.canAddOutput(videoOutput)
self.session?.addOutput(videoOutput)
// explanation here: https://dev59.com/DF0Z5IYBdhLWcg3wyy11#35642852
videoOutput.metadataObjectTypes = [AVMetadataObject.ObjectType.qr]
self.session?.startRunning()
}
} catch _ {
}
}
//MARK: AVCaptureVideoDataOutputSampleBufferDelegate
public func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
if let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) {
let cameraImage = CIImage(cvPixelBuffer: pixelBuffer)
// awesome stuff here
}
}
//MARK: AVCaptureMetadataOutputObjectsDelegate
func setMetadataObjectsDelegate(_ objectsDelegate: AVCaptureMetadataOutputObjectsDelegate?, queue objectsCallbackQueue: DispatchQueue?) {
}
}
需求:
Privacy - Camera Usage Description
innerView
必须被初始化, 我是通过以下限制条件使用Storyboard实现:这里是结果:
AVCaptureVideoDataOutputSampleBufferDelegate
+ AVCaptureVideoDataOutput
。 - mugx也许我来晚了一点,但我刚刚实现了QRScanner,并且根据运行视频流的设备可以进行缩放。这是通过AVCaptureDevice.videoZoomFactor
属性实现的。因此,为了增强小方形QRScanner的用户体验,可以通过在self.session?.startRunning()
之前插入以下行device.zoomFactor = min(YOUR_ZOOM_FACTOR_VALUE, device.activeFormat.videoMaxZoomFactor)
来略微修改上面的代码。