IOS相机变焦不工作xcode

Question

我用的是iOS 15.5版本的iPhone 13 pro。我使用的是XCode 13.3.1版本。我正在尝试用AVFoundation实现相机变焦。

下面是我试过的代码。此处选择的摄像头设备为.builtInTripleCamera。我想拍微距照片。我正在尝试不同的缩放系数，比如1.0、3.0和15.0。但相机预览并没有改变。我不确定这是否是目前获得放大相机预览以及输出的方法。有人设法正确设置相机变焦系数与AVFoundation吗?

private let captureSession = AVCaptureSession()
private lazy var previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
private let videoDataOutput = AVCaptureVideoDataOutput()
private var cameraDevice: AVCaptureDevice?

override func viewDidLoad() {
super.viewDidLoad()

self.setCameraInput()
self.setCameraOutput()
self.showCameraFeed()

self.captureSession.beginConfiguration()
self.captureSession.sessionPreset = AVCaptureSession.Preset.high;
self.captureSession.commitConfiguration()
self.captureSession.startRunning()
}

private func showCameraFeed() {
self.previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
self.view.layer.insertSublayer(self.previewLayer, at: 1)
self.previewLayer.frame = self.view.frame
//        self.view.addGestureRecognizer(pgr)
}


private func setCameraInput() {
let deviceTypes: [AVCaptureDevice.DeviceType]
if #available(iOS 13, *) {
deviceTypes = [.builtInTripleCamera, .builtInDualWideCamera, .builtInDualCamera, .builtInWideAngleCamera]
} else {
deviceTypes = [.builtInDualCamera, .builtInWideAngleCamera]
}

let session = AVCaptureDevice.DiscoverySession(
deviceTypes: deviceTypes,
mediaType: .video,
position: .back
)

guard let device = session.devices.first else {
fatalError("No back camera device found.")
}
cameraDevice = device
addInputToSession(device: cameraDevice!, session: self.captureSession)
}


private func addInputToSession(device:AVCaptureDevice,session:AVCaptureSession){
let cameraInput = try! AVCaptureDeviceInput(device: device)
if(session.canAddInput(cameraInput)){

do{
try device.lockForConfiguration()
cameraInput.device.videoZoomFactor = 15
session.addInput(cameraInput)
device.unlockForConfiguration()
}catch{
print(error)
}
}
}

private func setCameraOutput() {
self.videoDataOutput.videoSettings = [(kCVPixelBufferPixelFormatTypeKey as NSString) : NSNumber(value: kCVPixelFormatType_32BGRA)] as [String : Any]
self.videoDataOutput.alwaysDiscardsLateVideoFrames = true
self.videoDataOutput.setSampleBufferDelegate(self, queue: DispatchQueue(label: "camera_frame_processing_queue"))
self.captureSession.addOutput(self.videoDataOutput)
guard let connection = self.videoDataOutput.connection(with: AVMediaType.video),
connection.isVideoOrientationSupported else { return }
connection.videoOrientation = .portrait
}

Answer 1

使用缩放识别器处理相机缩放

cameraDevice.videoZoomFactor 

并将其设置为识别器的。began状态，如下所示

@objc private func viewPinched(recognizer: UIPinchGestureRecognizer) {
switch recognizer.state {
case .began:
recognizer.scale = cameraDevice.videoZoomFactor
case .changed:
let scale = recognizer.scale
do {
try cameraDevice.lockForConfiguration()
cameraDevice.videoZoomFactor = max(cameraDevice.minAvailableVideoZoomFactor, min(scale, cameraDevice.maxAvailableVideoZoomFactor))
cameraDevice.unlockForConfiguration()
}
catch {
print(error)
}
default:
break
}
}