Question

我正在尝试创建一个转换以下QR码的CIFilter：

要：

以下是我正在使用的代码：

let invert = CIFilter(name: "CIColorInvert")
invert!.setDefaults()
invert!.setValue(ciImage, forKey: "inputImage")

let filter = CIFilter(name: "CIColorMatrix")
filter?.setDefaults()
filter?.setValue(invert?.outputImage, forKey: kCIInputImageKey)

let r = CGFloat(70.0/255.0)
let g = CGFloat(224.0/255.0)
let b = CGFloat(182.0/255.0)

filter?.setValue(CIVector(x: r, y: 0, z: 0, w: 0), forKey: "inputRVector")
filter?.setValue(CIVector(x: 0, y: g, z: 0, w: 0), forKey: "inputGVector")
filter?.setValue(CIVector(x: 0, y: 0, z: b, w: 0), forKey: "inputBVector")
filter?.setValue(CIVector(x: 0, y: 0, z: 0, w: 1), forKey: "inputAVector")

代码所做的是首先反转正常的QR码，使其在白色上为黑色，然后拍摄该图像并在其上应用滤镜。代码的结果是：

这不是我想要的颜色。我将不胜感激任何帮助！

谢谢！

Answer 1

您可以使用以下方法之一使用QR filter effect来实现coreImage。

<强>输出：

方法1： Using Custom Filter

Step1:为class创建单独的custom kernel，如下所示。

class CustomFilter: CIFilter {
var inputImage: CIImage?

override public var outputImage: CIImage! {
    get {
        if let inputImage = self.inputImage {
            let args = [inputImage as AnyObject]
            return createCustomKernel().apply(withExtent: inputImage.extent, arguments: args)
        } else {
            return nil
        }
      }
    }
 }


func createCustomKernel() -> CIColorKernel {
let kernelString =
    "kernel vec4 chromaKey( __sample s) { \n" +
        "  vec4 newPixel = s.rgba;" +
        "  newPixel[0] = 0.0;" +
        "  newPixel[2] = newPixel[2] / 2.0;" +
        "  return newPixel;\n" +
"}"
return CIColorKernel(string: kernelString)!
 }

在您的ViewController中，您可以声明自定义过滤器，如下所示。

 var context = CIContext(options: nil)

 func customQRFilter() {

    let myInvertFilter = CIFilter(name: "CIColorInvert")
    myInvertFilter!.setValue(CIImage(image: imageView.image!), forKey: kCIInputImageKey)
    let output = myInvertFilter!.outputImage 

    let filter = CustomFilter()
    filter.setValue(output, forKey: kCIInputImageKey)

    // Get the filtered output image and return it
    let outputImage = filter.outputImage!
    let cgimg = context.createCGImage(outputImage,from: output!.extent)
    let processedImage = UIImage(cgImage: cgimg!)
    imageView.image = processedImage
   }

方法2：使用CIColorMatrix过滤器。

    func colorMatrixFilter() {

    let myInvertFilter = CIFilter(name: "CIColorInvert")
    myInvertFilter!.setValue(CIImage(image: imageView.image!), forKey: kCIInputImageKey)
    let output = myInvertFilter!.outputImage 

    let filter = CIFilter(name: "CIColorMatrix")
    filter?.setDefaults()
    filter?.setValue(output, forKey: kCIInputImageKey)

    let r = CGFloat(0.0)
    let g = CGFloat(0.9)
    let b = CGFloat(0.416)

    filter?.setValue(CIVector(x: r, y: 0, z: 0, w: 0), forKey: "inputRVector")
    filter?.setValue(CIVector(x: 0, y: g, z: 0, w: 0), forKey: "inputGVector")
    filter?.setValue(CIVector(x: 0, y: 0, z: b, w: 0), forKey: "inputBVector")
    filter?.setValue(CIVector(x: 0, y: 0, z: 0, w: 1), forKey: "inputAVector")

    let outputs = filter?.outputImage 
    let cgimg = context.createCGImage(outputs!,from: output!.extent)
    let processedImage = UIImage(cgImage: cgimg!)
    imageView2.image = processedImage
}

注意：我建议您使用colour Picker tool来挑选您想要的RGB value of any colour。

Answer 2

我必须创建一个没有颜色空间的上下文来获得正确的颜色：

...
let ciContext = CIContext(options: [CIContextOption.outputColorSpace: NSNull(), CIContextOption.workingColorSpace: NSNull()])
let cgimg = ciContext.createCGImage(outputs!,from: output!.extent)
let processedImage = UIImage(cgImage: cgimg!)

（快速4）

CIColorMatrix过滤结果很奇怪

2 个答案: