Setting up CIFilter in Swift

Question

How does one translate the last line of the following ObjC code to Swift:

CGAffineTransform transform = CGAffineTransformIdentity;
CIFilter *clampFilter = [CIFilter filterWithName:@"CIAffineClamp"];

[clampFilter setValue:[NSValue valueWithBytes:&transform objCType:@encode(CGAffineTransform)] forKey:@"inputTransform"];

The following line

clampFilter.setValue(transform, forKey: "inputTransform")

produces

Type 'CGAffineTransform' does not conform to protocol 'AnyObject'

Answer 1

NSValue has a constructor that takes a CGAffineTransform argument:

let transform = CGAffineTransformIdentity
let clampFilter = CIFilter(name: "CIAffineClamp")

let val = NSValue(CGAffineTransform: transform)
clampFilter.setValue(val, forKey: "inputTransform")

Update for Swift 3:

let transform = CGAffineTransform.identity
let clampFilter = CIFilter(name: "CIAffineClamp")!
let val = NSValue(cgAffineTransform: transform)
clampFilter.setValue(val, forKey: "inputTransform")

Answer 2

This might do.

var transform = CGAffineTransformIdentity;
var clampFilter = CIFilter(name: "CIAffineClamp")
var value = NSValue(CGAffineTransform: transform)
clampFilter.setValue(value, forKey: "inputTransform")