ios - 透明背景变白

Question

我正在将具有透明背景的图像上传到 Firebase。当我以某种方式下载它时，背景变白了。知道如何解决这个问题吗？

这是我的 putData 函数。

let uploadData = imageview.image!.jpegData(compressionQuality: 0.75)
let uploadTask = imagesRef.putData(uploadData!, metadata: nil, completion: { (metadata, error) in
    guard let metadata = metadata else {
        return
    } 

这里是下载函数。

URLSession.shared.dataTask(with: NSURL(string: imageURL as! String)! as URL, completionHandler: { (data, response, error) -> Void in
    if error != nil {
        print("ERROR LOADING IMAGES FROM URL: \(String(describing: error))")
        DispatchQueue.main.async {
            imageView.image = UIImage()
        }
        return
    }

    DispatchQueue.main.async {
        if let downloadedImage = UIImage(data: data!) {
            imageCache.setObject(downloadedImage, forKey: NSString(string: imageURL!))
            imageView.image = downloadedImage
        }
    }
}).resume()

Answer 1

I'm uploading an image with a transparent background to firebase. The background becomes white when I downloaded it somehow. Any idea how to fix this?

您做对了，除了您得到的是 JPEG 而不是 PNG 数据；)请记住 JPEG 不支持透明 BG。

希望对您有所帮助!