修复使用前置摄像头拍摄的图像的方向 ios

Question

我使用 Swift 在我的应用中使用自定义相机实现。当图像被捕获时，被称为func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?)。我使用 photo.fileDataRepresentation() 获取图像数据，之后我使用 UIImage.

上的以下扩展来修复照片的方向

func fixedOrientation() -> UIImage? {
    guard imageOrientation != UIImage.Orientation.up else {
        // This is default orientation, don't need to do anything
        return self.copy() as? UIImage
    }
    
    guard let cgImage = self.cgImage else {
        // CGImage is not available
        return nil
    }
    
    guard let colorSpace = cgImage.colorSpace, let ctx = CGContext(data: nil, width: Int(size.width), height: Int(size.height), bitsPerComponent: cgImage.bitsPerComponent, bytesPerRow: 0, space: colorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue) else {
        return nil // Not able to create CGContext
    }
    
    var transform = CGAffineTransform.identity
    
    switch imageOrientation {
    case .down, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: size.height)
        transform = transform.rotated(by: CGFloat.pi)
    case .left, .leftMirrored:
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.rotated(by: CGFloat.pi / 2.0)
    case .right, .rightMirrored:
        transform = transform.translatedBy(x: 0, y: size.height)
        transform = transform.rotated(by: CGFloat.pi / -2.0)
    case .up, .upMirrored:
        break
    @unknown default:
        break
    }
    
    // Flip image one more time if needed to, this is to prevent flipped image
    switch imageOrientation {
    case .upMirrored, .downMirrored:
        transform = transform.translatedBy(x: size.width, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)
    case .leftMirrored, .rightMirrored:
        transform = transform.translatedBy(x: size.height, y: 0)
        transform = transform.scaledBy(x: -1, y: 1)
    case .up, .down, .left, .right:
        break
    @unknown default:
        break
    }
    
    ctx.concatenate(transform)
    
    switch imageOrientation {
    case .left, .leftMirrored, .right, .rightMirrored:
        ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.height, height: size.width))
    default:
        ctx.draw(cgImage, in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
    }
    
    guard let newCGImage = ctx.makeImage() else { return nil }
    return UIImage(cgImage: newCGImage, scale: 1, orientation: .up)
}

显然这对于使用后置摄像头拍摄的图像效果很好，但使用正面摄像头时我遇到了问题。

如果自拍照片是人像，方法returns照片镜像。（这没什么大不了的）
如果自拍照片是横向拍摄的 right/left，输出代码是照片也被镜像但错误地旋转了。这是我需要你帮助的地方，以正确旋转照片。

注意：我也在旋转设备时将 videoOrientation 从 AVCaptureConnection 更改。

Answer 1

事实证明，我在更改 videoOrientation 时旋转确实发生了变化，这是错误的。在拍摄照片之前，我必须移动该逻辑。现在它工作正常。如果使用前置摄像头，我还通过将 isVideoMirrored 设置为 true 来解决镜像问题。

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