Swift Core Image filter over filtered image

Question

my problem is as follows: I made a simple app with a uiviewcontroller and an uiview(FilterView). om my view I added a UIButton and a UIImageView. What I want is that when you push the button a SepiaFilter is applied to the image:

 func sepiaButtonClicked( sender:UIButton ){

    let context = CIContext(options: nil)
    let image = CIImage(image: theView.imageView.image)

    let filter = CIFilter(name: "CISepiaTone", withInputParameters: [
        kCIInputImageKey : image,
        kCIInputIntensityKey : NSNumber(double: 0.5)

        ])
    let imageWithFilter = filter.outputImage

    theView.imageView.image = UIImage(CIImage: imageWithFilter)

}    

theView refers to the UIView with this piece of code on top

var theView:FilterView {
    get {
        return view as! FilterView
    }
}

now when I push the button the filter is applied as I wanted it to happen, but if you would press it again afterwards it gives a fatal error 'unexpectedly found nil while unwrapping an Optional value'. this is I think the image ( the one I enter for kCIInputImageKey ).

Can anyone give me an explanation on why this is happening? I can't figure out the difference between the first and second click on the button.. how I see it this code just replaces the UIImage with the new one and it should be ready to be triggered again?

Thx in advance,

Pieter-Jan De Bruyne

Answer 1

Try this :

 func sepiaButtonClicked( sender:UIButton ){
  var CurrentImage = self.imageView.image
 var inputImage = CIImage(image:CurrentImage)
let filter = CIFilter(name:"CISepiaTone")
 filter.setValue(inputImage, forKey: kCIInputImageKey)
 filter.setValue(0.5, forKey: kCIInputIntensityKey) 
let context = CIContext(options: nil)
let imageWithFilter = filter.outputImage
let NewOuptutImage =  context.createCGImage(imageWithFilter  , fromRect: imageWithFilter.extent())
imageView.image =  UIImage(CGImage: NewOuptutImage)
 }