Question

通过编程，我已经在应用程序中从相机捕获了图像。它已经很好地获取了，但是当我转移到另一个视图时，当时想查看并关闭该视图，我想将其旋转为风景。我从相机拍摄了图像。当我从照片库中获取图像时，没有发现问题。

以下图像是我的原始图像。 Screen Shot

我想旋转图像。 Screen Shot

以下代码：

var captureSesssion : AVCaptureSession!
var cameraOutput : AVCapturePhotoOutput!
var previewLayer : AVCaptureVideoPreviewLayer!
var device:AVCaptureDevice!
var currentViewControl = UIViewController()
var tempImageHolder = UIImage()

func beginCamera(_ targetView: UIView, _ currentVC: UIViewController) 
{ 
    currentViewControl = currentVC
    // Do any additional setup after loading the view, typically from a nib.
    captureSesssion = AVCaptureSession()
    captureSesssion.sessionPreset = AVCaptureSession.Preset.photo
    cameraOutput = AVCapturePhotoOutput()

    if #available(iOS 11.1, *) {
        let availableDevices = AVCaptureDevice.DiscoverySession(deviceTypes: [.builtInWideAngleCamera, .builtInTelephotoCamera, .builtInTrueDepthCamera], mediaType: AVMediaType.video, position: .back).devices
        device = availableDevices.first
    } else {
        // Fallback on earlier versions
        device = AVCaptureDevice.default(for: .video)!
    }

    if let input = try? AVCaptureDeviceInput(device: device!) {
        if (captureSesssion.canAddInput(input)) {
            captureSesssion.addInput(input)
            if (captureSesssion.canAddOutput(cameraOutput)) {
                captureSesssion.addOutput(cameraOutput)
                let connection = cameraOutput.connection(with: AVFoundation.AVMediaType.video)
                connection?.videoOrientation = .portrait
                previewLayer = AVCaptureVideoPreviewLayer(session: captureSesssion)
                self.previewLayer.frame = targetView.frame
                self.previewLayer.videoGravity = AVLayerVideoGravity.resizeAspectFill
                //setOutputOrientation()
                targetView.layer.addSublayer(previewLayer)
                captureSesssion.startRunning()
            }
        } else {
            print("issue here : captureSesssion.canAddInput")
        }
    } else {
        print("some problem here")
    }
    previewLayer?.frame.size = targetView.frame.size
}

   func image(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeRawPointer) {
    if let error = error {
        // we got back an error!
        let alert = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "OK", style: .default))
        currentViewControl.present(alert, animated: true)
    } else {
    }}


 func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
    let imageData = photo.fileDataRepresentation()
    let imageSize: Int = imageData!.count
    print(imageSize)
    tempImageHolder = UIImage(data: (imageData! as NSData) as Data)!
    //When use this below line works fine when take images from left landscape, but when take images from right landscape image not show properly screen shot below:
    tempImageHolder = UIImage(cgImage: tempImageHolder.cgImage!, scale: tempImageHolder.scale, orientation: .up)
    }
}

从左侧风景拍摄图像时：

输入： Screen Shot

输出： Screen Shot

从正确的风景拍摄图像

输入： Screen Shot

输出： Screen Shot

UIImage(cgImage: tempImageHolder.cgImage!, scale: tempImageHolder.scale, orientation: .up)

使用此行时，从左风景拍摄图像时效果很好，但是从右风景拍摄图像时无法正确显示屏幕截图

有人可以向我解释如何旋转图像。任何帮助将不胜感激。

谢谢。

Answer 1

这是一个非常烦人的问题，我真的不敢相信AVFoundation对我们没有任何帮助。但是在我的应用程序中，我通过保持当前设备方向来实现此目的。当照片输出随图像返回时，请使用方向旋转图像以确保所有图像均朝上显示。

class MyViewController: UIViewController {

    var currentOrientation: UIDeviceOrientation = .portrait

    override func viewDidLoad() {
        NotificationCenter.default.addObserver(self, selector: #selector(orientationChanged), name: UIDevice.orientationDidChangeNotification, object: nil)
    }

    @objc func orientationChanged() {
        currentOrientation = UIDevice.current.orientation
    }

    func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
        guard let img = photo.cgImageRepresentation()?.takeUnretainedValue() else { return }
        let temp = CIImage(cgImage: img)
        var ciImage = temp;
        switch currentOrientation {
            case .portrait:
                ciImage = temp.oriented(forExifOrientation: 6)
            case .landscapeRight:
                ciImage = temp.oriented(forExifOrientation: 3)
            case .landscapeLeft:
                ciImage = temp.oriented(forExifOrientation: 1)
            default:
                break
        }

        guard let cgImage = CIContext(options: nil).createCGImage(ciImage, from: ciImage.extent) else { return }
        let fixedImage = UIImage(cgImage: cgImage)
    }


}

最后，根据需要使用 fixedImage 。请注意，我订阅通知中心以更改方向。

Answer 2

enum CGImageOrientation {
case up
case down
case left
case right
case upMirrored
case downMirrored
case leftMirrored
case rightMirrored
}

  extension CGImage {
   func orientImage(_ imageOrientation: CGImageOrientation) -> 
   CGImage? {
    return orientImageWithTransform(imageOrientation).0
 }

func orientImageWithTransform(_ imageOrientation: CGImageOrientation) -> (CGImage?, CGAffineTransform) {

    var transform = CGAffineTransform.identity
    if imageOrientation == .up { return (self.copy(), transform)}


    let size = CGSize(width: width, height: height)
    let newSize = [.left,.leftMirrored, .right, .rightMirrored].contains(imageOrientation)
        ? CGSize(width: size.height, height: size.width) : size

    // Guard that we have color space and core graphics context.
    guard let colorSpace = self.colorSpace,
        // New graphic context uses transformed width and height.
        let ctx = CGContext(data: nil, width: Int(newSize.width), height: Int(newSize.height),
                            bitsPerComponent: self.bitsPerComponent, bytesPerRow: 0,
                            space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue)
        else { return (nil, transform)}

    // OK, now the actual work of constructing transform and creating new image.
    switch imageOrientation {
    case .down, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: size.height)
        transform = transform.rotated(by: CGFloat.pi)
        break
    case .left,.leftMirrored:
        transform = transform.translatedBy(x: size.height, y: 0)
        transform = transform.rotated(by: CGFloat.pi/2)
        break
    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: size.width)
        transform = transform.rotated(by: -CGFloat.pi/2)
        break
    case .up, .upMirrored:
        break
    }

    if [.upMirrored, .downMirrored,.leftMirrored, .rightMirrored].contains(imageOrientation) {
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)
    }

    ctx.concatenate(transform)
    // Interestingly, drawing with the original width and height?!
    // So width and height here are pre-transform.

    ctx.draw(self, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))

    return (ctx.makeImage(), transform)
}

}

要使用：-

var tempImage = imgae
        guard let cgImage = imgae?.cgImage else {return}

        if let orientedImage = cgImage.orientImage(.upMirrored) {
            tempImage = UIImage(cgImage: orientedImage)
        }
        let image = UIImageView(image: tempImage)

Answer 3

存在的问题是，将UIImage转换为CGImage时，您将丢弃图像元数据（包括方向）。如我在此post

中所示，您需要先渲染新的UIImage，然后才能访问其cgImage属性。

if let data = photo.fileDataRepresentation(), let image = UIImage(data: data) {
    let renderedImage = UIGraphicsImageRenderer(size: size, format: imageRendererFormat).image { _ in image.draw(at: .zero) }
    // use renderedImage image
}

Answer 4

从iOS 4.0开始，当相机拍摄照片时，它不会旋转保存之前，它

只需在JPEG的EXIF数据中设置旋转标记。如果将UIImage保存为JPEG

它将设置旋转标记。PNG不支持旋转标记。

因此，如果将UIImage另存为PNG，它将被错误地旋转并且没有设置用于修复它的标志。因此，如果您想要PNG图片，则必须自己旋转它们。

func rotateImage(image: UIImage) -> UIImage? {
            if (image.imageOrientation == UIImage.Orientation.up ) {
                return image
            }
            UIGraphicsBeginImageContext(image.size)
            image.draw(in: CGRect(origin: CGPoint.zero, size: image.size))
            let copy = UIGraphicsGetImageFromCurrentImageContext()
            UIGraphicsEndImageContext()
            return copy
        }

从相机捕获的iPhone图像自动旋转Swift

4 个答案: