Impostazione CIFilter a Swift

Question

Come si fa a tradurre l'ultima riga del seguente codice objC a Swift:

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

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

La seguente riga

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

produce

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

Answer 1

NSValue ha un costruttore che accetta un argomento CGAffineTransform:

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

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

Aggiornamento per Swift 3:

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

Answer 2

Questo potrebbe fare.

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