I was trying to modify the slidervalue used in the applyProcessing() function when the filter is colorPosterize.

The issue I am finding is there does not seem to be a matching kCIInput key that matches levels the docs say it needs an NSNumber and the name is Levels. Similar to how Sepia uses Intensity

So I thought there would be a kCIInputLevelsKey but that doesnt work...

Can anyone help?

   //code below works
   if inputKeys.contains(kCIInputScaleKey) && (currentFilter.name == "CIPixellate") {
      print("this is pixellate")
      currentFilter.setValue(scaleIntensity * 75, forKey: kCIInputScaleKey) }

    //code below doesnt run as I do not think the Contains is finding the correct kCI key

    if inputKeys.contains(kCIInputIntensityKey) && (currentFilter.name == "CIColorPosterize") {
        print("this is the posterize effect")
      currentFilter.setValue(filterIntensity * 10, forKey: kCIInputIntensityKey) }

That worked perfect! I actually tried a string but I think I put in Levels instead of inputLevels... Here is my code which works awesome!

Thank you so much @roosterboy !!

 func applyProcessing() {
    print(currentFilter.name)
    let inputKeys = currentFilter.inputKeys
    print(inputKeys)

    if inputKeys.contains(kCIInputIntensityKey) {
      currentFilter.setValue(filterIntensity, forKey: kCIInputIntensityKey) }
    if inputKeys.contains(kCIInputRadiusKey) {
      currentFilter.setValue(filterIntensity * 200, forKey: kCIInputRadiusKey) }
    if inputKeys.contains(kCIInputScaleKey) {
      currentFilter.setValue(scaleIntensity * 10, forKey: kCIInputScaleKey) }
    if inputKeys.contains(kCIInputScaleKey) && (currentFilter.name == "CIPixellate") {
      print("this is pixellate")
      currentFilter.setValue(scaleIntensity * 75, forKey: kCIInputScaleKey) }
    if inputKeys.contains("inputLevels") && (currentFilter.name == "CIColorPosterize") {
        print("this is the posterize effect")
      currentFilter.setValue(filterIntensity * 30, forKey: "inputLevels")
    }

    guard let outputImage = currentFilter.outputImage else { return }

    if let cgimg = context.createCGImage(outputImage, from: outputImage.extent) {
      let uiImage = UIImage(cgImage: cgimg)
      image = Image(uiImage: uiImage)
      processedImage = uiImage
    }
  }