Kingfisher processor that replaces #FFFFFF with transparent color

WhiteToTransparentProcessor.swift

import Foundation
import Kingfisher
import CoreImage

private let colorCubeData: [Float] = [
    0, 0, 0, 1,
    1, 0, 0, 1,
    0, 1, 0, 1,
    1, 1, 0, 1,
    0, 0, 1, 1,
    1, 0, 1, 1,
    0, 1, 1, 1,
    0, 0, 0, 0
]

private let cubeData = NSData(bytes: colorCubeData, length: colorCubeData.count * MemoryLayout<Float>.size)

struct WhiteToTransparentProcessor: CIImageProcessor {
    let identifier = "com.ouroboros.WhiteToTransparent"

    let filter = Filter { input in
        guard let colorCube = CIFilter(name: "CIColorCube", withInputParameters: [
            "inputCubeDimension": 2,
            "inputCubeData": cubeData,
            kCIInputImageKey: input]) else {
                return nil
        }
        
        return colorCube.outputImage
    }
}