How to use CIFilter CiColorCube

Question

can someone explain me, how does this filter works, i saw WWDC 2012 and documentation and still don't understand quite. Where and how to define cube color map. Is it in .h or .m file? I have ViewController.h and .m, where i working with some filters and i need to use CiColorCube filter but i just don't know how. This is my code:

- (void)viewDidLoad
{
    // here i would like to use CIColorCube
    CIImage *inputImage = [[CIImage alloc]initWithImage:[UIImage imageNamed:@"background.jpg"]];
    CIImage *inputBackgroundImg = [[CIImage alloc]initWithImage:[UIImage imageNamed:@"image.jpeg"]];
    CIContext *context = [CIContext contextWithOptions:nil];
    vignette = [CIFilter filterWithName:@"CIVignette"];
    [vignette setValue:inputImage forKey:kCIInputImageKey];
    [vignette setValue:[NSNumber numberWithFloat:2.5] forKey:@"inputRadius"];
    [vignette setValue:[NSNumber numberWithFloat:2.9] forKey:@"inputIntensity"];
    sourceOC = [CIFilter filterWithName:@"CISourceOverCompositing"];
    [sourceOC setValue:vignette.outputImage forKey:kCIInputImageKey];
    [sourceOC setValue:inputBackgroundImg forKey:@"inputBackgroundImage"];
    maskToAlpha = [CIFilter filterWithName:@"CIMaskToAlpha"];
    [maskToAlpha setValue:inputImage forKey:kCIInputImageKey];
    CIImage *outputImage = maskToAlpha.outputImage;
    imageView.image = [UIImage imageWithCGImage:[context createCGImage:outputImage fromRect:outputImage.extent]];
    [super viewDidLoad];
}

Answer 1

In Apple's Developer Library, there is a document on 'Subclassing CIFilter: Recipes for Custom Effects' that shows how to make the color map..

Also, in XCode you can look up the ImageApp sample code, and it also shows how in ImageFilter.m.