在 swift 3 中上传到 Firebase 存储之前调整 UIImage 的大小

Question

我已经设置了我的应用程序，以便当我按下"cambiaimmagineutente"按钮时，会出现一个选择器控制器，我可以选择图像，然后使用"UIImagePickerControllerReferenceURL"上传到FIRStorage。我找不到在上传图像之前调整图像大小的方法以节省空间并将其放置在较小的图像视图中。这是代码：

 @IBAction func cambiaImmagineUtente(_ sender: UIButton) {
        imagePicker.allowsEditing = false
        imagePicker.sourceType = .photoLibrary
        present(imagePicker, animated: true, completion:nil)
    }
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    picker.dismiss(animated: true, completion:nil)

    // if it's a photo from the library, not an image from the camera
    if #available(iOS 8.0, *), let referenceUrl = info[UIImagePickerControllerReferenceURL] as? URL {
        let assets = PHAsset.fetchAssets(withALAssetURLs: [referenceUrl], options: nil)
        let asset = assets.firstObject
        asset?.requestContentEditingInput(with: nil, completionHandler: { (contentEditingInput, info) in
            let imageFile = contentEditingInput?.fullSizeImageURL
            let filePath = FIRAuth.auth()!.currentUser!.uid +
            "/(Int(Date.timeIntervalSinceReferenceDate * 1000))/(imageFile!.lastPathComponent)"
            // [START uploadimage]
            self.storageRef.child(filePath)
                .putFile(imageFile!, metadata: nil) { (metadata, error) in
                    if let error = error {
                        //an error occured
                        print("Error uploading: (error)")
                        return
                    }
                    self.uploadSuccess(metadata!, storagePath: filePath)
            }
            // [END uploadimage]
        })
    } else {
        guard let image = info[UIImagePickerControllerOriginalImage] as? UIImage else { return }
        guard let imageData = UIImageJPEGRepresentation(image, 0.8) else { return }
        let imagePath = FIRAuth.auth()!.currentUser!.uid +
        "/(Int(Date.timeIntervalSinceReferenceDate * 1000)).jpg"
        let metadata = FIRStorageMetadata()
        metadata.contentType = "image/jpeg"
        self.storageRef.child(imagePath)
            .put(imageData, metadata: metadata) { (metadata, error) in
                if let error = error {
                    //an error occured
                    print("Error uploading: (error)")
                    return
                }
                self.uploadSuccess(metadata!, storagePath: imagePath)
        }
    }
}
func uploadSuccess(_ metadata: FIRStorageMetadata, storagePath: String) {
    print("Upload Succeeded!")
    //self.urlTextView.text = metadata.downloadURL()?.absoluteString
    UserDefaults.standard.set(storagePath, forKey: "storagePath")
    UserDefaults.standard.synchronize()
    //self.downloadPicButton.isEnabled = true
}
func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    picker.dismiss(animated: true, completion:nil)
}

Answer 1

你可以使用这个：

 func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage {
        let size = image.size
        let widthRatio  = targetSize.width  / image.size.width
        let heightRatio = targetSize.height / image.size.height
        var newSize: CGSize
        if(widthRatio > heightRatio) {
            newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
        } else {
            newSize = CGSize(width: size.width * widthRatio,  height: size.height * widthRatio)
        }
        let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
        UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
        image.draw(in: rect)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage!
    }

用：

let resizedImage = resizeImage(image: selectedImage, targetSize: CGSize.init(width: 300, height: 300))

请确保在存储规则中将写入规则设置为最大值！