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i want to display an image with transparent background using swift userdefault

I'm developing an application with swift, saving png images with UserDefaults and displaying them on multiple screens
When creating an image, I want to reflect it because it is made transparent

Error message 
I can display it on the screen, but when I read it, the background becomes white without being transparent
Applicable source code 
Save
UserDefaults.standard.set (selectedImage! .JpegData (compressionQuality: 1.0), forKey: "imageData")
Read
let imageDate: NSData = UserDefaults.standard.object (forKey: "imageData") as! NSData
        selectedFriends.image = UIImage (data: imageDate as Data)

If i put the image in the imageview as it is, the background is transparent, so there is no problem with the image itself

Supplemental information (FW/tool version etc.)

Swift version is 5

swift
  • Answer # 1 

    selectedImage! .jpegData (compressionQuality: 1.0)


    Isn't it a problem to extract NSData in JPEG format?
    What happens if I extract it in PNG format using pngData ()?

  • Answer # 2

    JPEG format does not have the concept of transparency.
    Even if the image is transparent, the transparency information will be lost when converted to JPEG.

    And

    let imageDate: NSData = UserDefaults.standard.object (forKey: "imageData") as! NSData


    However,nilis returned when there is nothing in UserDefaults at the first startup.
    Be careful as force cast can fail.

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