CI internal error, type mismatch between kernel parameter 1 and argument

Question

I am trying to create a CIColorClampFilter https://developer.apple.com/library/mac/documentation/GraphicsImaging/Reference/CoreImageFilterReference/index.html#//apple_ref/doc/filter/ci/CIColorClamp

It says I can set a key for "inputMinComponents" as a [0,0,0,0] or whatever RGB values I want.

But this code:

filter = CIFilter(name:"CIColorClamp")
filter.setValue(ciImage, forKey: kCIInputImageKey)
filter.setValue([0,0,0,0], forKey: "inputMinComponents")

Causes this error:

CI internal error, type mismatch between kernel parameter 1 and argument

I've look around for other CIColorClamp examples but found nothing.

Do you know whats wrong with the value I'm trying to pass for the "inputMinComponents" key?

Answer 1

Apparently swift's smart casting does not work you must explcitly create a CIVector

filter = CIFilter(name:"CIColorClamp")
filter.setValue(ciImage, forKey: kCIInputImageKey)
var lowerLevel = CIVector(x: 0.1, y: 0.1, z: 0.3, w: 0)
filter.setValue(lowerLevel, forKey: "inputMinComponents")
var upperLevel = CIVector(x: 0.5, y: 0.7, z: 0.9, w: 1)
filter.setValue(upperLevel, forKey: "inputMaxComponents")