Swift 为什么UIImagePNGRepresentation()返回nil?当我尝试存储新图像时
我正在生成二维码的UIImage,并希望将其存储。但是当UIImagePngResentation将UIImage转换为数据时,它总是返回nil。请帮帮我Swift 为什么UIImagePNGRepresentation()返回nil?当我尝试存储新图像时,swift,uiimage,uiimagepngrepresentation,Swift,Uiimage,Uiimagepngrepresentation,我正在生成二维码的UIImage,并希望将其存储。但是当UIImagePngResentation将UIImage转换为数据时,它总是返回nil。请帮帮我 public func generaImagenQR(texto:String)->UIImage?{ let data = texto.data(using: String.Encoding.ascii) //Generate a QR code if let filter = CIFilter(name: "
public func generaImagenQR(texto:String)->UIImage?{
let data = texto.data(using: String.Encoding.ascii)
//Generate a QR code
if let filter = CIFilter(name: "CIQRCodeGenerator") {
filter.setValue(data, forKey: "inputMessage")
let transform = CGAffineTransform(scaleX: 3, y: 3)
if let output = filter.outputImage?.applying(transform) {
return UIImage(ciImage: output)
}
}
return nil
}
let imagenDeQR = generaImagenQR(texto: "hola")
let data = UIImagePNGRepresentation(imagenDeQR!)
// data == nil !!!
UIImagePNGRepresentation
的文档是“将图像返回为PNG。如果图像没有CGImageRef或无效的位图格式,则可能返回nil”,我知道,但UIImage有一个有效的图像(我在视图中看到了图片),但它仍然不起作用