在CALayer上使用自定义CIFilter显示CALayer没有变化

我假设你在代码中没有显示的地方做了这件事:

self.view.wantsLayer = true

但你也会想这样做:

self.view.layerUsesCoreImageFilters = true
    

结果 没有 这条线:

结果 具有 这条线:

(不管怎样,不要问我为什么“CIGaussianBlur”有效……)

编辑 -我用来产生上述输出的确切代码:

import CoreImage

class ViewController: NSViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.view.wantsLayer = true
        self.view.layerUsesCoreImageFilters = true
        
        // Create some layers to work with! (square with gradient color)
        let mainLayer = CALayer()
        let shapeLayer = CAShapeLayer()
        let gradientLayer = CAGradientLayer()
        gradientLayer.colors = [NSColor.red.cgColor, NSColor.white.cgColor, NSColor.yellow.cgColor, NSColor.black.cgColor]
        
        shapeLayer.path = CGPath(rect: CGRect(x: 0, y: 0, width: 500, height: 500), transform: nil)
        shapeLayer.fillColor = CGColor.black
        
        gradientLayer.frame = CGRect(x: 0, y: 0, width: 500, height: 500)
        gradientLayer.mask = shapeLayer
        
        gradientLayer.setAffineTransform(CGAffineTransform(translationX: 50, y: 50))
        mainLayer.addSublayer(gradientLayer)
        
        mainLayer.filters = []
        self.view.layer?.addSublayer(mainLayer)

        // Register the custom filter
        CustomFilterRegister.register()
        
        let t = 2
        
        if t == 1 {
            // Test with a normal image file, WORKS!
            if let image = NSImage(named: "test"), let cgImage = image.cgImage(forProposedRect: nil, context: nil, hints: nil) {
                if let filter = CIFilter(name: "CustomFilter") {
                    filter.setValue(CIImage(cgImage: cgImage), forKey: kCIInputImageKey)
                    let output = filter.outputImage
                    // WORKS! Image filtered as expected!
                    print()
                }
            }
        }
        
        else if t == 2 {
            // 
            // Does NOT work. No change in color of the layer!
            // 
            // This NOW works for me
            // 
            if let filter = CIFilter(name: "CustomFilter") {
                filter.name = "custom"
                mainLayer.filters?.append(filter)
            }
            
        } else {
            
            // This works: mainLayer and sublayers are blurred!
            if let filter = CIFilter(name: "CIGaussianBlur") {
                filter.name = "blur"
                mainLayer.filters?.append(filter)
            }
            
        }
        
    }
}

class CustomFilter: CIFilter {
    
    // Error in xcode if you don't add this in!
    override class var supportsSecureCoding: Bool {
        return true
    }
    
    @objc dynamic var inputImage: CIImage?
    @objc dynamic var inputSaturation: CGFloat = 1
    @objc dynamic var inputBrightness: CGFloat = 0
    @objc dynamic var inputContrast: CGFloat = 1
    override func setDefaults() {
        inputSaturation = 1
        inputBrightness = 0
        inputContrast = 2
    }
    
    override public var outputImage: CIImage? {
        guard let image = inputImage else {
            return nil
        }
        return image.applyingFilter("CIPhotoEffectProcess")
            .applyingFilter("CIColorControls", parameters: [
                kCIInputSaturationKey: inputSaturation,
                kCIInputBrightnessKey: inputBrightness,
                kCIInputContrastKey: inputContrast
            ])
    }
}

class CustomFilterRegister: CIFilterConstructor {
    static func register() {
        CIFilter.registerName(
            "CustomFilter", constructor: CustomFilterRegister(),
            classAttributes: [
                kCIAttributeFilterCategories: [kCICategoryBlur, kCICategoryVideo, kCICategoryStillImage]
            ])
    }
    func filter(withName name: String) -> CIFilter? {
        switch name {
        case "CustomFilter":
            return CustomFilter()
        default:
            return nil
        }
    }
}

编辑

奇怪的是,如果我添加一个计数器var和 print() 这样的陈述:

var applyCount: Int = 0

override public var outputImage: CIImage? {
    print("getting outputImage...")
    guard let image = inputImage else {
        return nil
    }
    applyCount += 1
    print("apply", applyCount)
    return image.applyingFilter("CIPhotoEffectProcess")
        .applyingFilter("CIColorControls", parameters: [
            kCIInputSaturationKey: inputSaturation,
            kCIInputBrightnessKey: inputBrightness,
            kCIInputContrastKey: inputContrast
        ])
}

在macOS 10.15.4/XXcode 12.4上,我在调试控制台中得到以下结果:

getting outputImage...
apply 1
getting outputImage...
apply 2
getting outputImage...
apply 3
getting outputImage...
apply 4
getting outputImage...
apply 5
getting outputImage...
apply 6
getting outputImage...
apply 7
getting outputImage...
apply 8
getting outputImage...
apply 9
getting outputImage...
apply 10
getting outputImage...
apply 11
getting outputImage...
apply 12
getting outputImage...
apply 13
getting outputImage...
apply 14
getting outputImage...
apply 15
getting outputImage...
apply 16

(例如,当窗口改变大小时,它会继续被重复调用)。

但是,在macOS 11.4/Xcode 12.5.1上运行时,我得到 没有什么 在调试控制台中。。。 outputImage 从未被请求?

正如@DonMag所指出的那样,它应该与他所描述的变化相一致。多么不幸的是,我们今天收到了苹果的回复;

此时,有一个错误阻止CALayer上的自定义CIFilters工作。目前还没有解决此错误的方法。

当我们提交bug时,我会在这里为感兴趣的人添加链接。但此时,您无法在macOS 11上向CALayer添加自定义CIFilter。

让我们希望他们能为所有阅读本文的人解决这个问题。

编辑 :

那么坏消息。。。目前在macOS 12.2.1上,它仍然存在同样的问题,根据我们的工单没有发生任何事情。苹果似乎不想解决这个问题。对于那些正在寻找的人:这仍然不适用于 CALayer 即使有其他答案中描述的所有选项。内置 CIFilter 按预期工作。

请注意,使用相同的自定义 CIFilter 在a CALayer 对于导出使用 AVVideoCompositionCoreAnimationTool 工作!