UIImage to NSData for Core Data in Swift 3.0

Question

以前，在Swift 2.2中，我可以使用Entity.image = UIImagePNGRepresentation(UIImage(named: "Image Name")!)

但是现在在Swift 3.0中，我们必须使用一个额外的步骤。Entity.image = NSData(data: UIImagePNGRepresentation(UIImage(named: "Image Name")!))或UIImage(name: "Image Name")的等效物

Swift 3.0是否有新的方式从UIImage到NSData ?

Answer 1

试试这个:

if let img = UIImage(named: "hallo.png") {
    let data = UIImagePNGRepresentation(img) as NSData?
}

Answer 2

为了安全执行代码，使用if-let块与数据，作为函数UIImagePNGRepresentation返回，可选值。

if let img = UIImage(named: "Hello.png") {
    if let data:Data = UIImagePNGRepresentation(img) {
       // Handle operations with data here...         
    }
}

注:Data是Swift 3类。用Data代替NSData with斯威夫特3

通用图像操作(如png &jpg):

if let img = UIImage(named: "Hello.png") {
        if let data:Data = UIImagePNGRepresentation(img) {
               handleOperationWithData(data: data)     
        } else if let data:Data = UIImageJPEGRepresentation(img, 1.0) {
               handleOperationWithData(data: data)     
        }
}
*******
func handleOperationWithData(data: Data) {
   // Handle operations with data here...
}

使用扩展名:

extension UIImage {
    var pngRepresentationData: Data? {
        return UIImagePNGRepresentation(self)
    }
    var jpegRepresentationData: Data? {
        return UIImageJPEGRepresentation(self, 1.0)
    }
}
*******
if let img = UIImage(named: "Hello.png") {
      if let data = img.pngRepresentationData {
              handleOperationWithData(data: data)     
      } else if let data = img.jpegRepresentationData {
              handleOperationWithData(data: data)     
      }
}
*******
func handleOperationWithData(data: Data) {
     // Handle operations with data here...
}

Answer 3

对于Swift 4，这要容易得多:

let imageData = image.jpegData(compressionQuality: 0)

当然，压缩质量是您设置的一个变量。0表示最大压缩，1表示最小压缩。

Answer 4

使用UIImagePNGRepresentation将UIImage转换为Data有时会导致数据转换回来时图像失真，因为在初始转换时从原始数据中删除了一些基本元数据。

经过一番研究，我最终使用以下代码将UIImage转换为Data:

let image = UIImage(named: "whatever")
var data: Data?
if let cgImage = image.cgImage, cgImage.renderingIntent == .defaultIntent {
    data = UIImageJPEGRepresentation(image, 0.8)
}
else {
    data = UIImagePNGRepresentation(image)
}

Answer 5

使用PNG或JPG图像作为数据

PNGself.imgProfilePic.image ! .pngData ()

JPEGself. imgprofileic .image!.jpegData(compressionQuality: 1.0)//质量最小= 0.0到最大= 1.0

Answer 6

使用扩展名获取PNG或JPG imageData作为NSData。

extension UIImage {
    var jpegRepresentationData: NSData! {
        return UIImageJPEGRepresentation(self, 1.0)! as NSData   // QUALITY min = 0 / max = 1
    }
    var pngRepresentationData: NSData! {
        return UIImagePNGRepresentation(self)! as NSData
    }
}
//use
imageView.image!.jpegRepresentationData or
imageView.image!.pngRepresentationData