Question

我正在尝试旋转CMSampleBuffer（来自相机）的像素数据并将其显示在UIImageView中。我不想旋转视图本身。它必须是实际的像素数据。

我抓住了Feed，将其转换为CIImage并使用CIFilter旋转它。我在设置它必须旋转的点时遇到了麻烦。现在它围绕左下角旋转。我想围绕它的中心旋转它。

 func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {

            //create pixelbuffer

            let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
            let context = CIContext.init(options: nil)

            // calculating the radians to rotate the ciimage by
            let radians : Float = atan2f(Float(boxView!.transform.b), Float(boxView!.transform.a));
            //create ciimage from the pixelbuffer

            let options = [kCVPixelBufferCGImageCompatibilityKey as String: true,
                kCVPixelBufferCGBitmapContextCompatibilityKey as String: true,]
            let ci = CIImage.init(cvPixelBuffer: pixelBuffer, options: options)
            //transform filter
            let filter = CIFilter.init(name: "CIAffineTransform")
            //set translation point to center
            var transform = CGAffineTransform(translationX: self.view.frame.midX, y: self.view.frame.midY)
            //rotate
            transform = CGAffineTransform(rotationAngle:CGFloat(radians))
            // set translation point back again to normal
            var transformBack = CGAffineTransform(translationX: -self.view.frame.midX, y: -self.view.frame.midY)
            //applying the transform
            transform.concatenating(transformBack)

            filter!.setValue(transform, forKey: kCIInputTransformKey)
            filter!.setValue(ci, forKey: kCIInputImageKey)
            let output = filter?.outputImage
            let img = context.createCGImage(output!, from: imageView!.frame)
            // send image to be displayed
            self.imageView!.image = UIImage(cgImage: img!)

}

Answer 1

找到了它。我必须将转换应用于转换变量本身。

let transform = CGAffineTransform(translationX: self.view.frame.midX, y: self.view.frame.midY).rotate(angle: CGFloat(radians)).translatedBy(x: -self.view.frame.midX, y: -self.view.frame.midY)

Answer 2

快捷键5：

let image = CIImage(cvPixelBuffer: yourBuffer)
let rotatedImage = image.oriented(forExifOrientation: Int32(CGImagePropertyOrientation.right.rawValue))

对此有一个明确的API：Docs

使用CIFilter围绕中心旋转CIImage

2 个答案: