无法使用 UISlider 降低 CIVignette 效果

Question

我为我的照片编辑应用程序使用了CIVignette 效果。它基于 Slider 的变化事件应用。我使用了以下代码，我的问题是每当我增加滑块的值时出现晕影效果，但每当我降低滑块的值时，晕影效果不会降低。
请帮忙。

@IBAction func slider(_ sender: UISlider) {

        let startImage = CIImage(image: imgEdited!)!

        let vignetteFilter = CIFilter(name: "CIVignette")!

        let radius = 5

        vignetteFilter.setValue(startImage, forKey:kCIInputImageKey)
        vignetteFilter.setValue(sender.value, forKey:"inputIntensity")
        vignetteFilter.setValue(radius, forKey:"inputRadius")

        let filteredImageData = vignetteFilter.value(forKey: kCIOutputImageKey) as! CIImage
        let filteredImageRef = self.context.createCGImage(filteredImageData, from: filteredImageData.extent)

        imgImage.image = UIImage.init(cgImage: filteredImageRef!)
        self.imgEdited = imgImage.image
}

Answer 1

以下代码基于我对其他SO 帖子Blur effect using slider Is not working properly 的回答。

 @IBAction func slider(_ sender: UISlider) {

    let startImage = CIImage(image: UIImage(named: "Your Image Name")!) // You should initialise your UIImage here not UIImageView
    let vignetteFilter = CIFilter(name: "CIVignette")! 

    vignetteFilter.setValue(startImage, forKey:kCIInputImageKey)
    vignetteFilter.setValue(sender.value, forKey:kCIInputIntensityKey)
    vignetteFilter.setValue(5, forKey:kCIInputRadiusKey)

    let filteredImageData = vignetteFilter.value(forKey: kCIOutputImageKey) as! CIImage
    let filteredImageRef = self.context.createCGImage(filteredImageData, from: filteredImageData.extent)

    self.imgView.image = UIImage.init(cgImage: filteredImageRef!) // Output

 }

模拟市民的输出：