I have a image with pixel size: 3024 * 3024 I have a custom UIView with logical size: 207 * 207, and layer.contentsScale is 3, so pixel size is 621 * 621. I want to draw this UIImage in my custom UIView, the code in draw(rect:) like this; var image: UIImage? { didSet { setNeedDisplay() } } override func draw(_ rect: CGRect) {     guard let ctx = UIGraphicsGetCurrentContext() else { return }     ctx.addRect(bounds)     ctx.setFillColor(UIColor.black.cgColor)     ctx.fillPath()           if var im = image {        let size = Math.getMaxSizeWithAspect(size: CGSize(width: bounds.width, height: bounds.height), radioWidthToHeight: im.size.width / im.size.height)        im.draw(in: CGRect(x: (bounds.width - size.width) / 2, y: (bounds.height - size.height) / 2, width: size.width, height: size.height)) } and the result is very bad, picture is aliasing, I tried much solution, but not work well. // not work list... ctx.setShouldAntialias(true) ctx.setAllowsAntialiasing(true) ctx.interpolationQuality = .high layer.allowsEdgeAntialiasing = true layer.minificationFilter = .trilinear

I am using AVCaptureVideoDataOutput to capture each frame from camera capture. I display these frame to MTKView. that's fine. If I call AVCapturePhotoOutput.capturePhoto, the delegate function AVCaptureVideoDataOutput.captureOutput will be paused, so that my preview had a little freezed, that's very bad. I don't know if I do something wrong cause this? this is my capturePhoto code: func createTakePhotoSettingForNormalPhoto() - AVCapturePhotoSettings { var settings: AVCapturePhotoSettings settings.isHighResolutionPhotoEnabled = true return settings } func takePhoto() { settings = createTakePhotoSettingForNormalPhoto() settings.flashMode = ... _outputStillImage.capturePhoto(with: settings, delegate: self) } I noticed that if I tap shot button repeatly and quickly in IOS native Camera APP, it will have a black flash at each shot, but the preview also could display frame smoothly.

I want use Metal kernel function to calculate histogram of a video frame(texture) some code in kernel function like this float gray = grayScale(rgbValue); int histogramIndex = int(clamp(gray, 0.0, 1.0) * 255); histogram[histogramIndex] += 1; it works, but there was some mistake, I sum up every item value in array histogram, the sum result is not equals to my texture pixel count. it's always less than total pixel count. so I think there must be a multi-thread sync problem. so how could I sync the kernel function? I know MPS provided a MPSImageHistogram to do this, It works well, I just want to calculate histogram on my pipeline. Thanks

I got a RAW Image CGImage from file, its pixel format is CV14BayerRggb 1919379252 then, convert it to MTLTexture RGBA16Uint then, modify some pixel color and write to another MTLTexture RGBA16Uint then, I want to create a CIImage from output texture, there raised a error told me create CIImage failed, unsupported texutre format.