如何使用 Swift 将后置摄像头变焦级别设置为 0.5 倍？

Question

我有使用 AVFoundation 实现的自定义相机的缩放功能（1 倍以上）。在 iPhone X 机型之前这一切都很好。但我希望 iPhone 11 和 iPhone 11 Pro 设备具有 0.5 倍变焦。

我编写的代码无法将其设置为 0.5 倍缩放。我已经尝试了所有可能的组合[.builtInTripleCamera, .builtInDualWideCamera, .builtInUltraWideCamera]。具有设备类型的捕获设备.builtinUltraWideCamera未给出 0.5 minAvailableVideoZoomFactor。

在 iPhone 11 上进行测试时，我还[.builtInDualCamera, .builtInTelephotoCamera, .builtInWideAngleCamera, .builtInTrueDepthCamera]从deviceTypes.

感谢任何解决此问题的帮助。下面是适用于 1 倍变焦以上的代码。

/// Called from -handlePinchGesture
private func zoom(_ scale: CGFloat) {
    let captureDevice = cameraDevice(.back)
            
    do {
        try captureDevice?.lockForConfiguration()

        var minZoomFactor: CGFloat = captureDevice?.minAvailableVideoZoomFactor ?? 1.0
        let maxZoomFactor: CGFloat = captureDevice?.maxAvailableVideoZoomFactor ?? 1.0
        
        if #available(iOS 13.0, *) {
            if captureDevice?.deviceType == .builtInDualWideCamera || captureDevice?.deviceType == .builtInTripleCamera || captureDevice?.deviceType == .builtInUltraWideCamera {
                minZoomFactor = 0.5
            }
        }
        zoomScale = max(minZoomFactor, min(beginZoomScale * scale, maxZoomFactor))
        captureDevice?.videoZoomFactor = zoomScale

        captureDevice?.unlockForConfiguration()
    } catch {
        print("ERROR: locking configuration")
    }
}

@objc private func handlePinchGesture(_ recognizer: UIPinchGestureRecognizer) {
    var allTouchesOnPreviewLayer = true
    let numTouch = recognizer.numberOfTouches
    
    for i in 0 ..< numTouch {
        let location = recognizer.location(ofTouch: i, in: view)
        let convertedTouch = previewLayer.convert(location, from: previewLayer.superlayer)
        if !previewLayer.contains(convertedTouch) {
            allTouchesOnPreviewLayer = false
            break
        }
    }
    if allTouchesOnPreviewLayer {
        zoom(recognizer.scale)
    }
}

func cameraDevice(_ position: AVCaptureDevice.Position) -> AVCaptureDevice? {
    var deviceTypes = [AVCaptureDevice.DeviceType]()
    deviceTypes.append(contentsOf: [.builtInDualCamera, .builtInTelephotoCamera, .builtInWideAngleCamera, .builtInTrueDepthCamera])
    
    if #available(iOS 13.0, *) {
        deviceTypes.append(contentsOf: [.builtInTripleCamera, .builtInDualWideCamera, .builtInUltraWideCamera])
    }

    let availableCameraDevices = AVCaptureDevice.DiscoverySession(deviceTypes: deviceTypes, mediaType: .video, position: position).devices

    guard availableCameraDevices.isEmpty == false else {
        debugPrint("ERROR: No camera devices found!!!")
        return nil
    }

    for device in availableCameraDevices {
        if device.position == position {
            return device
        }
    }

    guard let defaultDevice = AVCaptureDevice.default(for: AVMediaType.video) else {
        debugPrint("ERROR: Can't initialize default back camera!!!")
        return nil
    }
    return defaultDevice
}

Answer 1

针对希望将光学变焦级别设置为 0.5 倍的用户进行更新

礼貌： https: //github.com/NextLevel/NextLevel/issues/187

public class func primaryVideoDevice(forPosition position: AVCaptureDevice.Position) -> AVCaptureDevice? {
    
    // -- Changes begun
    if #available(iOS 13.0, *) {

        let hasUltraWideCamera: Bool = true // Set this variable to true if your device is one of the following - iPhone 11, iPhone 11 Pro, & iPhone 11 Pro Max
        
        if hasUltraWideCamera {

            // Your iPhone has UltraWideCamera.
            let deviceTypes: [AVCaptureDevice.DeviceType] = [AVCaptureDevice.DeviceType.builtInUltraWideCamera]
            let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: deviceTypes, mediaType: AVMediaType.video, position: position)
            return discoverySession.devices.first
            
        }
        
    }
    // -- Changes end
    

    var deviceTypes: [AVCaptureDevice.DeviceType] = [AVCaptureDevice.DeviceType.builtInWideAngleCamera] // builtInWideAngleCamera // builtInUltraWideCamera
    if #available(iOS 11.0, *) {
        deviceTypes.append(.builtInDualCamera)
    } else {
        deviceTypes.append(.builtInDuoCamera)
    }
    
    // prioritize duo camera systems before wide angle
    let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: deviceTypes, mediaType: AVMediaType.video, position: position)
    for device in discoverySession.devices {
        if #available(iOS 11.0, *) {
            if (device.deviceType == AVCaptureDevice.DeviceType.builtInDualCamera) {
                return device
            }
        } else {
            if (device.deviceType == AVCaptureDevice.DeviceType.builtInDuoCamera) {
                return device
            }
        }
    }
    
    return discoverySession.devices.first
    
}