Ios 使用CIFilter围绕中心旋转CIImage

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

我抓取提要，将其转换为CIImage，然后用CIFilter旋转它。 我在设置旋转点时遇到问题。 现在它围绕左下角点旋转。我想绕着它的中心旋转

 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!)

}

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找到了。我必须对转换变量本身应用转换

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)

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Swift 5:

let image = CIImage(cvPixelBuffer: yourBuffer)
let rotatedImage = image.oriented(.right)

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谢谢你的帮助。在寻找一个更简单的解决方案之前，我对三角学失去了兴趣。平移、旋转和向后平移就足够了。也许在数学方面，它可能会表现得更好，但就目前而言，这将起到作用。：）再次感谢你！！我认为答案是关于CIImage，而不是UIView，这可能会让读者感到困惑。你是什么意思？我的问题是关于CIImage的，我明确表示我想旋转CIImage而不是UIView，所以我的答案是正确的。非常简单。谢谢正是我需要的。