How to optimize filter performance CIFilter

Question

static func effectTransfer(image: UIImage) -> UIImage {
    let coreImage = CIImage(image: image)
    let filter = CIFilter(name: "CIPhotoEffectTransfer" )
    filter!.setDefaults()
    filter!.setValue(coreImage, forKey: kCIInputImageKey)
    let filteredImageData = filter!.value(forKey: kCIOutputImageKey) as! CIImage
    let filteredImageRef = ciContext.createCGImage(filteredImageData, from: filteredImageData.extent)

    return UIImage(cgImage: filteredImageRef!)
}

When you click on a filter, the filter is applied extremely slowly, and the processor grows for a second or two to 60%, how can I optimize it? Am I doing it right?

Answer 1

The slowest part is converting to CGImage. You can create UIImage directly from CIImage:

UIImage(ciImage: outputCI, scale: input.scale, orientation: input.imageOrientation)