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Saving a Xamarin image to file

Hi so I'm trying to save an image selected by the user to file so that i can later upload it to my mySQL database.
So I have this code:
var result = await MediaPicker.PickPhotoAsync(new MediaPickerOptions
{
Title = "Please pick a selfie"
});
var stream = await result.OpenReadAsync();
resultImage.Source = ImageSource.FromStream(() => stream);
string path = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string filename = Path.Combine(path, "myfile");
using (var streamWriter = new StreamWriter(filename, true))
{
streamWriter.WriteLine(GetImageBytes(stream).ToString());
}
using (var streamReader = new StreamReader(filename))
{
string content = streamReader.ReadToEnd();
System.Diagnostics.Debug.WriteLine(content);
}
Here's the GetImageBytes(..) function:
private byte[] GetImageBytes(Stream stream)
{
byte[] ImageBytes;
using (var memoryStream = new System.IO.MemoryStream())
{
stream.CopyTo(memoryStream);
ImageBytes = memoryStream.ToArray();
}
return ImageBytes;
}
The code kind of works, it creates a file but doesn't save the image. Instead it saves "System.Bytes[]". It saves the name of the object, not the contents of the object.
myfile
enter image description here
Any help would be really appreciated. Thanks!

StreamWriter is for writing formatted strings, not binary data. Try this instead
File.WriteAllBytes(filename,GetImageBytes(stream));

Encode the byte array as a base64 string, then store that in the file:
private string GetImageBytesAsBase64String(Stream stream)
{
var imageBytes;
using (var memoryStream = new System.IO.MemoryStream())
{
stream.CopyTo(memoryStream);
imageBytes = memoryStream.ToArray();
}
return Convert.ToBase64String(imageBytes);
}
If you later need to retrieve the image bytes from the file, you can use the corresponding Convert.FromBase64String(imageBytesAsBase64String) method.

Sevenzipsharp CompressStream throws Exception: Value cannot be null

I am trying out following code in order to compress and save a bitmap of a screenshot but get this error. I haven't tried using CompressFiles as I have to do it using memory stream.
public void CompressAndSaveBitmap(Bitmap bitmap)
{
using (MemoryStream memStream = new MemoryStream())
{
using (FileStream file = new FileStream("XYZ", FileMode.Create, System.IO.FileAccess.Write))
{
bitmap.Save(memStream, System.Drawing.Imaging.ImageFormat.Bmp);
// tried these but they don't work.
//memStream.Seek(0, 0);
//memStream.Position = 0;
this.compressor.CompressStream(memStream, file); // throws error here
// also tried the following to see if Bitmap contains the problem
//UnicodeEncoding uniEncoding = new UnicodeEncoding();
//byte[] firstString = uniEncoding.GetBytes("Invalid file path characters are: ");
//int count = 0;
//while (count < firstString.Length)
//memStream.WriteByte(firstString[count++]);
//memStream.Flush();
////memStream.Seek(0, 0);
//memStream.Position = 0;
//this.compressor.CompressStream(memStream, file);
}
}
}
Compressor initialization code:
public Compressor()
{
SevenZipCompressor.SetLibraryPath(#"D:\7z.dll");
this.compressor = new SevenZip.SevenZipCompressor();
compressor.CompressionLevel = CompressionLevel.Ultra;
compressor.CompressionMethod = CompressionMethod.Ppmd;
}
It's crashes on this line in the library:
var lockObject = (object) _files ?? _streams;
lock (lockObject) // here in ArchiveUpdateCallback.cs
I see that the file is created but it's corrupt.

I was able to successfully compress file using following code:
public void CompressAndSaveBitmap(Bitmap bitmap)
{
using (MemoryStream memStream = new MemoryStream())
{
using (FileStream file = new FileStream("XYZ", FileMode.Create, System.IO.FileAccess.Write))
{
bitmap.Save(memStream, System.Drawing.Imaging.ImageFormat.Bmp);
// tried these but they don't work.
//memStream.Seek(0, 0);
//memStream.Position = 0;
SevenZipCompressor compressor =
new SevenZipCompressor
{
CompressionLevel = CompressionLevel.Ultra,
CompressionMethod = CompressionMethod.Lzma
};
compressor.CompressStream(memStream, file); // throws error here
}
}
}
Following was the bitmap file:
Executed code:
Bitmap bmp = new Bitmap("Test.bmp");
res.CompressAndSaveBitmap(bmp);
After execution got following output:
Opened the file with WinRar and extracted file:
In folder found the extracted image:
UPDATE:
I think the only problem with OP's code is this.compressor is not initialized.

Write bytes to End Of File PNG format

I have a resource file contain a PNG file I want to write byte array to the End Of File PNG image but when saving the file from stream remove byte array, I want to write hidden bytes to PNG file, How to resolve this issue?
public void Method()
{
using (var reader = new ResourceReader("My.resource"))
{
var iter = reader.GetEnumerator();
var ms = new MemoryStream();
var writer = new System.Resources.ResourceWriter(ms);
while (iter.MoveNext())
{
var key = iter.Key as string;
var value = iter.Value as Bitmap;
MemoryStream stream = new MemoryStream();
value.Save(stream, value.RawFormat);
byte[] b = new byte[] {0x11, 0x22, 0x33};
stream.Write(b, 0, b.Length);
Image bitmap = Image.FromStream(stream);
writer.AddResource(key, bitmap);
}
writer.Generate();
File.WriteAllBytes("My1.resource", ms.ToArray());
}
}

getting the same directory structure after decompressing a zipped file

I downloaded the zip file from the amazon server(using AWS SDK for unity).The zip file has a folder which has one more folder inside it which contains png files.When I got the response object from the amazon server,I read it as a byte array and stored as a .zip file. When I double click on zip file I get directory and subdirectory inside it containing png files.Now I need to programatically unzip the file. I am trying to use GZipStream to decompress it,which returns the uncompressed byte array.Now how can I save this byte array so that I retain my folder structure?Also I don't want to use the third party library to decompress the zipped file.
void Start()
{
UnityInitializer.AttachToGameObject (this.gameObject);
client = new AmazonS3Client (mAccKey, mSecretKey, mRegion);
Debug.Log ("Getting the presigned url\n");
GetPreSignedUrlRequest request = new GetPreSignedUrlRequest ();
request.BucketName = mBucketName;
request.Key = mFileName;
request.Expires = DateTime.Now.AddMinutes (5);
request.Protocol = Protocol.HTTP;
GetObjectRequest requestObject = new GetObjectRequest ();
requestObject.BucketName = mBucketName;
requestObject.Key = mFileName;
Debug.Log ("Requesting for the " + mFileName + " contents" + "from the bucket\n" + mBucketName);
client.GetObjectAsync(mBucketName, mFileName, (responseObj) =>
{
var response = responseObj.Response;
if (response.ResponseStream != null)
{
Debug.Log("Recieving response\n");
using (BinaryReader bReader=new BinaryReader(response.ResponseStream))
{
byte[] buffer = bReader.ReadBytes((int)response.ResponseStream.Length);
var zippedPath=Application.persistentDataPath+"/"+zippedFile;
File.WriteAllBytes(zippedPath,buffer);
var unZippedPath=Application.persistentDataPath+"/"+unZipToFolder;
DirectoryInfo directory=Directory.CreateDirectory(unZippedPath);
byte[]compressedData=compress(buffer);
byte[] unCompressedData=decompress(compressedData);
//Debug.Log(unCompressedData.Length);
File.WriteAllBytes(unZippedPath+directory,unCompressedData);
}
Debug.Log("Response complete");
}
});
}
#region GZipStream
public static byte[] compress(byte[] data)
{
using (MemoryStream outStream = new MemoryStream())
{
using (GZipStream gzipStream = new GZipStream(outStream, CompressionMode.Compress))
using (MemoryStream srcStream = new MemoryStream(data))
CopyTo(srcStream, gzipStream);
return outStream.ToArray();
}
}
public static byte[] decompress(byte[] compressed)
{
using (MemoryStream inStream = new MemoryStream(compressed))
using (GZipStream gzipStream = new GZipStream(inStream, CompressionMode.Decompress))
using (MemoryStream outStream = new MemoryStream())
{
CopyTo(gzipStream, outStream);
return outStream.ToArray();
}
}
public static void CopyTo(Stream input, Stream output)
{
byte[] buffer = new byte[16 * 1024];
int bytesRead;
while ((bytesRead = input.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, bytesRead);
}
}
#endregion
}
folder structure inside the zip file images->sample images->10 png files

GZipStream can only (de)compress streams. In other words, you cannot restore folder structure using it. Use ZipFile or, if you cannot use framework 4.5, SharpZipLib.

BitMapImage to byte and reverse

Since two days I try to manage my images in a WPF application but I have errors and errors errors, ...
The image is show in a System.Windows.Control.Image.
For this reason I try to work with variable BitMapImage.
Now I have the error : "Impossible to access close stream" and I can not find a solution.
I have created two function for convert :
public static BitmapImage ConvertToBitMapImage(byte[] bytes)
{
if (bytes == null || bytes.Length == 0) return null;
var image = new BitmapImage();
using (var mem = new MemoryStream(bytes))
{
mem.Position = 0;
image.BeginInit();
image.CreateOptions = BitmapCreateOptions.PreservePixelFormat;
image.CacheOption = BitmapCacheOption.OnLoad;
image.UriSource = null;
image.StreamSource = mem;
image.EndInit();
}
//image.Freeze();
return image;
}
public static byte[] ImageToByte(BitmapImage imageSource)
{
Stream stream = imageSource.StreamSource;
Byte[] buffer = null;
if (stream != null && stream.Length > 0)
{
using (BinaryReader br = new BinaryReader(stream))
{
buffer = br.ReadBytes((Int32)stream.Length);
}
}
return buffer;
}
In my object I have a property :
public BitmapImage MiniatureApp
{
get
{
if (IMAGES != null)
_MiniatureApp = Tools.BinaryImageConverter.ConvertToBitMapImage(IMAGES.IMAGE);
return _MiniatureApp;
}
set
{
if (this.IMAGES != null)
this.IMAGES.IMAGE = Tools.BinaryImageConverter.ImageToByte((BitmapImage)value);
else
{
IMAGES img = new IMAGES();
img.NOM = "";
img.IMAGE = Tools.BinaryImageConverter.ImageToByte((BitmapImage)value);
this.IMAGES = img;
}
NotifyPropertyChanged();
}
}
And in my main I do this :
FileStream fs = new FileStream(pathImage, FileMode.Open, FileAccess.Read);
byte[] data = new byte[fs.Length];
fs.Read(data, 0, System.Convert.ToInt32(fs.Length));
fs.Close();
VMAppareil.VMApp.CurrentAppareil.MiniatureApp = Tools.BinaryImageConverter.ConvertToBitMapImage(data);
Exist a solution for my problem or exist a best way to do this ?
Gobelet.

You can fix your solution replacing the ImageToByte method with the following (borrowed from https://stackoverflow.com/a/6597746/5574010)
public static byte[] ImageToByte(BitmapImage imageSource)
{
var encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(imageSource));
using (var ms = new MemoryStream())
{
encoder.Save(ms);
return ms.ToArray();
}
}
Your previous solution did not work because the ConvertToBitMapImage method close the stream that you assign to image.StreamSource as soon as your code exit the unit statement. When you call the ImageToByte method as part of the MiniatureApp setter the StreamSource will be close and you get an error.

I'm not really sure what you're doing with the getter-setter.
For getting a byte array from a file, I would have this:
public static byte[] FileToByteArray(string fileName)
{
byte[] fileData = null;
using (FileStream fs = new File.OpenRead(fileName))
{
var binaryReader = new BinaryReader(fs);
fileData = binaryReader.ReadBytes((int)fs.Length);
}
return fileData;
}
And once you have the bytes from that function, you can use ConvertToBitMapImage() and assign that to the Image.Source, like this:
byte[] bytes = FileToByteArray(fileName);
YourImage.Source = ConvertToBitMapImage(bytes);
I'm not sure why you would need to convert a BitmapImage into bytes, but you should be able to call your function directly for that:
BitmapImage bImg = new BitmapImage();
bImg.Source = ConvertToBitMapImage(bytes);
byte[] bytes = ImageToByte(bImg); // these should be the same bytes as went in
Set it up like this and step through the code to see where it snags. It's possible the bytes might need encoding when you grab it in ImageToByte().
But also, you don't just then set the byte[] directly to the IMAGES or this.IMAGES.IMAGE, because that isn't an Image object, it's a byte[]. Without knowing what your IMAGES model construct looks like with its property types, it's a little vague to know what is being set to what and why, but this seems like a bad idea to over-complicate what you should just do with function calls as it is needed, without a getter-setter and an IMAGES model in the way.