双指缩放相机

Question

我想捏一下来缩放相机，但我遇到了两个问题。首先是它允许用户放大太多和缩小太多，其次当我拍照时它不会拍摄放大的视图。这是我的捏功能代码...

func pinch(pinch: UIPinchGestureRecognizer) {
    if let view = cameraView {
        view.transform = CGAffineTransformScale(view.transform,
            pinch.scale, pinch.scale)
            pinch.scale = 1
    }

}

如果您需要查看更多代码，请告诉我。谢谢！

Answer 1

我在相机实施方面遇到了同样的问题。要解决这个问题，您需要了解两件事。

最大和最小变焦必须在一个值内，否则会导致相机放大太多。
与实际图像不保存放大图像一样，这是一个常见的错误，很多在线解决方案都没有涵盖。这实际上是因为您只是更改了视图的缩放比例，而不是实际 AVCaptureDevice 的缩放比例。

要更改这两件事，您需要这样的东西：

func pinch(pinch: UIPinchGestureRecognizer) {
   var device: AVCaptureDevice = self.videoDevice
   var vZoomFactor = ((gestureRecognizer as! UIPinchGestureRecognizer).scale)
   var error:NSError!
        do{
            try device.lockForConfiguration()
            defer {device.unlockForConfiguration()}
            if (vZoomFactor <= device.activeFormat.videoMaxZoomFactor){
                device.videoZoomFactor = vZoomFactor
            }else{
            NSLog("Unable to set videoZoom: (max %f, asked %f)", device.activeFormat.videoMaxZoomFactor, vZoomFactor);
            }
        }catch error as NSError{
             NSLog("Unable to set videoZoom: %@", error.localizedDescription);
        }catch _{

        }
}

如您所见，我为视频设备 (videoDevice) 使用了一个 class 变量来跟踪我用于视觉组件的捕获设备。我将缩放限制在特定范围内并更改设备上的缩放属性而不是视图本身！

Answer 2

    var device: AVCaptureDevice = self.backCamera
    var vZoomFactor = sender.scale
    var error:NSError!
    do{
        try device.lockForConfiguration()
        defer {device.unlockForConfiguration()}
        if (vZoomFactor <= device.activeFormat.videoMaxZoomFactor) {

            let desiredZoomFactor:CGFloat = vZoomFactor + atan2(sender.velocity, 5.0);
            device.videoZoomFactor = max(1.0, min(desiredZoomFactor, device.activeFormat.videoMaxZoomFactor));
        }
        else {

            NSLog("Unable to set videoZoom: (max %f, asked %f)", device.activeFormat.videoMaxZoomFactor, vZoomFactor);
        }
    }
    catch error as NSError{

        NSLog("Unable to set videoZoom: %@", error.localizedDescription);
    }
    catch _{

    }

Answer 3

如果需要手动zoomTo(2.0)功能，可以使用这个

// Create listener for Pinch to Zoom
let pinchRecognizer = UIPinchGestureRecognizer(target: self, action:#selector(FSCameraView.pinchToZoom(_:)))
pinchRecognizer.delegate = self
self.previewViewContainer.addGestureRecognizer(pinchRecognizer)

// set the zoom to a zoomed in mode from start
setZoom(CGFloat(2.0)



// and the functions
func pinchToZoom(sender:UIPinchGestureRecognizer) {
    var vZoomFactor = ((sender as! UIPinchGestureRecognizer).scale)
    setZoom(vZoomFactor)
}

func setZoom(zoomFactor:CGFloat) {
    var device: AVCaptureDevice = self.device!
    var error:NSError!
    do{
        try device.lockForConfiguration()
        defer {device.unlockForConfiguration()}
        if (zoomFactor <= device.activeFormat.videoMaxZoomFactor) {

            let desiredZoomFactor:CGFloat = zoomFactor + atan2(sender.velocity, 5.0);
            device.videoZoomFactor = max(1.0, min(desiredZoomFactor, device.activeFormat.videoMaxZoomFactor));
        }
        else {
            NSLog("Unable to set videoZoom: (max %f, asked %f)", device.activeFormat.videoMaxZoomFactor, zoomFactor);
        }
    }
    catch error as NSError{
        NSLog("Unable to set videoZoom: %@", error.localizedDescription);
    }
    catch _{
    }
}

Answer 4

要扩展 Ritvik Upadhyaya 的 答案，您还需要保存以前的缩放系数来计算新的缩放系数，您不希望缩放每次都重置为正常当您抬起手指并再次尝试缩放时。

// To track the zoom factor
var prevZoomFactor: CGFloat = 1

func pinch(pinch: UIPinchGestureRecognizer) {
    var device: AVCaptureDevice = self.videoDevice

    // Here we multiply vZoomFactor with the previous zoom factor if it exist. 
    // Else just multiply by 1
    var vZoomFactor = pinch.scale * prevZoomFactor

    // If the pinching has ended, update prevZoomFactor.
    // Note that we set the limit at 1, because zoom factor cannot be less than 1 or the setting device.videoZoomFactor will crash
    if sender.state == .ended {
        prevZoomFactor = zoomFactor >= 1 ? zoomFactor : 1
    }

    do {
        try device.lockForConfiguration()
        defer {device.unlockForConfiguration()}
        if (vZoomFactor <= device.activeFormat.videoMaxZoomFactor) {
            device.videoZoomFactor = vZoomFactor
        } else {
            print("Unable to set videoZoom: (max \(device.activeFormat.videoMaxZoomFactor), asked \(vZoomFactor))")
      }
    } catch {
        print("\(error.localizedDescription)")
    }
}

Answer 5

Swift 3.0 || 4.0

1.定义缩放级别。

let minimumZoom: CGFloat = 1.0
let maximumZoom: CGFloat = 3.0
var lastZoomFactor: CGFloat = 1.0

2。在 CameraView 上添加捏合手势。

let pinchRecognizer = UIPinchGestureRecognizer(target: self, action:#selector(pinch(_:)))        
            self.viewCamera.addGestureRecognizer(pinchRecognizer)

3。具有zoomin和zoom out

逻辑的捏动作方法

func pinch(_ pinch: UIPinchGestureRecognizer) {
        guard let device = videoDeviceInput.device else { return }

        // Return zoom value between the minimum and maximum zoom values
        func minMaxZoom(_ factor: CGFloat) -> CGFloat {
            return min(min(max(factor, minimumZoom), maximumZoom), device.activeFormat.videoMaxZoomFactor)
        }

        func update(scale factor: CGFloat) {
            do {
                try device.lockForConfiguration()
                defer { device.unlockForConfiguration() }
                device.videoZoomFactor = factor
            } catch {
                print("\(error.localizedDescription)")
            }
        }

        let newScaleFactor = minMaxZoom(pinch.scale * lastZoomFactor)

        switch pinch.state {
        case .began: fallthrough
        case .changed: update(scale: newScaleFactor)
        case .ended:
            lastZoomFactor = minMaxZoom(newScaleFactor)
            update(scale: lastZoomFactor)
        default: break
        }
    }

谢谢。快乐编码

Answer 6

您可以通过简单地将 UIPinchGestureRecognizer.scale 重置为 1 来避免保存 prevZoomFactor，如下所示：

    @IBAction func pinchAction(_ sender: UIPinchGestureRecognizer) {
        guard let device = currentCaptureDevice else {return}
        var zoom = device.videoZoomFactor * sender.scale
        sender.scale = 1.0
        var error:NSError!
        do{
            try device.lockForConfiguration()
            defer {device.unlockForConfiguration()}
            if zoom >= device.minAvailableVideoZoomFactor && zoom <= device.maxAvailableVideoZoomFactor {
                device.videoZoomFactor = zoom
            }else{
                NSLog("Unable to set videoZoom: (max %f, asked %f)", device.activeFormat.videoMaxZoomFactor, zoom);
            }
        }catch error as NSError{
            NSLog("Unable to set videoZoom: %@", error.localizedDescription);
        }catch _{
        }
    }

这是 Apple 在我参加的一次 WWDC 活动中推荐的，当时手势识别器刚刚问世。

Answer 7

Swift 5.0 或以上

1.定义变量声明和出口。

//#MARK: - Outlets
@IBOutlet weak var camPreview: UIView!

let minimumZoom: CGFloat = 1.0
let maximumZoom: CGFloat = 2.0
var lastZoomFactor: CGFloat = 1.0
var newCamera: AVCaptureDevice?

2。在相机视图上获取相机位置和捏合手势。

//#MARK: - Views methods    
  override func viewDidLoad() {
     super.viewDidLoad()
   // Do any additional setup after loading the view.
    newCamera = cameraWithPosition(position: .back)  
    //Add Pinch Gesture on CameraView.
      let pinchRecognizer = UIPinchGestureRecognizer(target: self, action:#selector(pinch(_:)))
       self.camPreview.addGestureRecognizer(pinchRecognizer)
  }

// Find a camera with the specified AVCaptureDevicePosition, returning nil if one is not found

  func cameraWithPosition(position: AVCaptureDevice.Position) -> AVCaptureDevice? {
      let discoverySession = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera], mediaType: AVMediaType.video, position: .unspecified)
      for device in discoverySession.devices {
            if device.position == position {
                return device
            }
       }
       return nil
  }

3。 Pinch-action 具有 zoom-in 和缩小功能。

  @objc func pinch(_ pinch: UIPinchGestureRecognizer) {
          guard let device = newCamera else { return }
    
          // Return zoom value between the minimum and maximum zoom values
          func minMaxZoom(_ factor: CGFloat) -> CGFloat {
                return min(min(max(factor, minimumZoom), maximumZoom), device.activeFormat.videoMaxZoomFactor)
          }
    
          func update(scale factor: CGFloat) {
               do {
                     try device.lockForConfiguration()
                     defer { device.unlockForConfiguration() }
                     device.videoZoomFactor = factor
                  } catch {
                     print("\(error.localizedDescription)")
                  }
          }
    
          let newScaleFactor = minMaxZoom(pinch.scale * lastZoomFactor)
    
          switch pinch.state {
                case .began: fallthrough
                case .changed: update(scale: newScaleFactor)
                case .ended:
                    lastZoomFactor = minMaxZoom(newScaleFactor)
                    update(scale: lastZoomFactor)
                default: break
                }
           }
  }

双指缩放相机

Pinch to zoom camera

iphone

camera

zooming

ios

swift

Swift 3.0 || 4.0