Develop Reference

How can I decode a byte array using a JpegBitmapDecoder

I cannot decode images back from their encoded form as a (Jpeg) byte array retrieved from my database to be used as image sources for my WPF application.
The code I am using to encode them as a Jpeg byte array is as follows:
public byte[] bytesFromBitmap(BitmapImage bit)
{
byte[] data;
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bit));
using (MemoryStream ms = new MemoryStream())
{
encoder.Save(ms);
data = ms.ToArray();
}
return data;
}
This is taking my Image taken directly from a webpage and assigned to an Image control like so:
var img = new BitmapImage(new Uri(entity.Image.ImageSrc)); //the entity has been saved in my DB, having been parsed from html
pbImage.Source = img;
This works just fine, I encode the BitmapImage and it saves just fine. But when I retrieve it from the DB and try to display it in another window, I cannot get it to work after trying every example I can see online - all either render nothing, or a black box or a visual mess not at all similar to the image I encoded.
Neither of the following have worked for me:
public BitmapSource GetBMImage(byte[] data)
{
using (var ms = new MemoryStream(data))
{
JpegBitmapDecoder decoder = new JpegBitmapDecoder(ms, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource frame = decoder.Frames[0];
return frame;
}
}
public static BitmapImage ImageFromBytes(byte[] imageData)
{
if (imageData == null)
{
return null;
}
else
{
var image = new BitmapImage();
using (var mem = new MemoryStream())
{
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;
}
} //this throws a 'No imaging component suitable to complete this operation was found' exception
Among other uses of memory streams and decoders I just can't get this to work - can anyone help?

Convert bitmapimage into byte array

I am trying to convert bitmap Image to Byte array. I have select all the image by using MediaLibrary class and added it into a list of bitmap images. Here is my code
using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication())
{
if (!store.DirectoryExists("ImagesZipFolder"))
{
store.CreateDirectory("ImagesZipFolder");
for (int i = 0; i < imgname.Count(); i++)
{
using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(#"ImagesZipFolder\" + imgname[i], System.IO.FileMode.CreateNew, store))
{
byte[] bytes = null;
using (MemoryStream ms = new MemoryStream())
{
WriteableBitmap wBitmap = new WriteableBitmap(ImgCollection[i]);
wBitmap.SaveJpeg(ms, wBitmap.PixelWidth, wBitmap.PixelHeight, 0, 100);
stream.Seek(0, SeekOrigin.Begin);
bytes = ms.GetBuffer();
stream.Write(bytes, 0, bytes.Length);
}
// byte[] bytes = Encoding.UTF8.GetBytes(imgname[i]);//new byte[ImgCollection[i].PixelWidth * ImgCollection[i].PixelHeight * 4];
// stream.Write(bytes, 0, bytes.Length);
}
}
}
else {
directory = true;
}
}
Basically what I am trying to do is, selecting all images or photo from device and create a zip file of that images. I was successful in creating a zip file of images. When I extract that file there is some images, but the problem is when I double click on image, I can't see that image. I think the problem is in reading the bytes of image. I am not getting what's wrong? Is my code is correct ?

Perhaps you can try the below. I know this code maintains the image, so if you have no luck using this, you may have a different issue.
// Convert the new image to a byte[]
ImageConverter converter = new ImageConverter();
byte[] newBA = (byte[])converter.ConvertTo(newImage, typeof(byte[]));
The ImageConverter is of the System.Drawing namespace.
Update:
http://msdn.microsoft.com/en-GB/library/system.windows.media.imagesourceconverter.convertto.aspx
You should be able to use this in place of the System.Drawing type I suggested.

There is no need to save the WriteableBitmap to a MemoryStream and then copy it to an IsolatedStorageFileStream. Just save the bitmap directly to the IsolatedStorageFileStream.
using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(#"ImagesZipFolder\" + imgname[i], System.IO.FileMode.CreateNew, store))
{
WriteableBitmap wBitmap = new WriteableBitmap(ImgCollection[i]);
wBitmap.SaveJpeg(stream, wBitmap.PixelWidth, wBitmap.PixelHeight, 0, 100);
}
This will allow you to save on memory as well. If you really want to save memory, you could reuse the WriteableBitmap.

I can' t use Image to Base64 String function

I'm making multi client chat server(done).
but I want to add image send.
I used this method when sending a message
client1 write message and getbyte -> Server -> getstring
So I'm coding like this (I can't this part)
load image -> ImageToBase64(image) -> getbyte --> server --> getstring-> Base64ToImage
Client Send part
how can i use this function and this method can be run.
private void button1_Click(object sender, EventArgs e)
{
Image screen;
screen=Image.FromFile("C:\\Users\\User\\Desktop\\Paint.bmp");
screentext = ImageToBase64(screen); //actually I do not know what parameter should be here
StreamWriter wrthr = new StreamWriter(#"C:\Users\User\Desktop\giden.txt");
wrthr.Write(screentext);
wrthr.Close(); // result empty txt
}
public string ImageToBase64(Image image, System.Drawing.Imaging.ImageFormat format)
{
using (MemoryStream ms = new MemoryStream())
{
// Convert Image to byte[]
image.Save(ms, format);
byte[] imageBytes = ms.ToArray();
// Convert byte[] to Base64 String
string base64String = Convert.ToBase64String(imageBytes);
return base64String;
}
}
public Image Base64ToImage(string base64String)
{
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(base64String);
MemoryStream ms = new MemoryStream(imageBytes, 0,
imageBytes.Length);
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
Image image = Image.FromStream(ms, true);
return image;
}

EDIT: There are two problems here...
Picking a second argument to ImageToBase64
It's up to you - do you want to keep it as a BMP file? If so, you don't really need to go via an Image at all... just load the bytes from Paint.bmp, and convert them directly into Base64:
byte[] bytes = File.ReadAllBytes(#"C:\Users\User\Desktop\Paint.bmp");
File.WriteAllText(#"C:\Users\User\Desktop\giden.txt",
Convert.ToBase64String(bytes));
Or you may wish to choose a different format, e.g. PNG or JPEG, e.g.
string screentext = ImageToBase64(screen, ImageFormat.Png);
(It's not clear where screentext is declared at the moment, but it should almost certainly be a local variable.)
Converting from base64...
This is the problem:
MemoryStream ms = new MemoryStream(imageBytes, 0,
imageBytes.Length);
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
You don't need the Write call, and it's actively harmful here:
You've constructed the MemoryStream with imageBytes, so it already contains that data
By writing to the stream, you've moved the "cursor" to the end... so there's nothing to read
Just use:
public Image Base64ToImage(string base64String)
{
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(base64String);
MemoryStream ms = new MemoryStream(imageBytes);
return Image.FromStream(ms, true);
}

Save Image source to database

I have a WPF Image with a source assign from picture dialog;
this.imgProduct.Source = new BitmapImage(new Uri(op.FileName));
How can I retieve the source, convert it to byte array and save it into database?
Thank you

You have to convert BitmapImage into the byte[] then save it to the database.
var imageSource = this.imgProduct.Source as BitmapImage;
var stream = imageSource.StreamSource;
Byte[] buffer = null;
if (stream != null && stream.Length > 0)
{
using (BinaryReader br = new BinaryReader(stream))
{
buffer = br.ReadBytes((Int32)stream.Length);
}
}
// write buffer to the database
P.S. I haven't tested the code but I think it works!

As long as you have access to the image file in op.FileName it would be very easy to get the file content by e.g.
byte[] imageBuffer = File.ReadAllBytes(op.FileName);
If the image is loaded from a file Uri (as in your example) you could also do this:
byte[] imageBuffer = File.ReadAllBytes(image.UriSource.AbsolutePath);
If you only have the BitmapImage without information about the file that it was loaded from (e.g. when it was loaded from a temporary file or a web resource), you would have to encode it by one of WPFs BitmapEncoders:
byte[] imageBuffer;
PngBitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(image));
using (MemoryStream stream = new MemoryStream())
{
encoder.Save(stream);
imageBuffer = stream.GetBuffer();
}

Bitmap to Base64String

i am trying to convert a bitmap to a base64 string.i can convert to from string to bitmap...but it seems like there is a problem when converting from bitmap to string.I was hoping you guys could give me a hand
public static string BitmapToString(BitmapImage image)
{
Stream stream = image.StreamSource ;
Byte[] buffer = null;
if (stream != null && stream.Length > 0)
{
using (BinaryReader br = new BinaryReader(stream))
{
buffer = br.ReadBytes((Int32)stream.Length);
}
}
return Convert.ToBase64String(buffer);
}
it gets a ArgumentNullException was unhandled
Value cannot be null.
Parameter name: inArray
when returning Convert.ToBase64String(buffer)
Help?

Try this alternative:
public string BitmapToBase64(BitmapImage bi)
{
MemoryStream ms = new MemoryStream();
PngBitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bi));
encoder.Save(ms);
byte[] bitmapdata = ms.ToArray();
return Convert.ToBase64String(bitmapdata);
}
In your solution, it is not necessary that StreamSource will always have value if it is loaded using a Uri.

First of all, it is necessary to save BitmapImage data into memory using some bitmap encoder (PngBitmapEncoder for example).
public static byte[] EncodeImage(BitmapImage bitmapImage)
{
using (MemoryStream memoryStream = new MemoryStream())
{
BitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmapImage));
encoder.Save(memoryStream);
return memoryStream.ToArray();
}
}
Then just encode the binary data with Base64-encoding.
const string filePath = #"...";
const string outFilePath = #"...";
const string outBase64FilePath = #"...";
// Constuct test BitmapImage instance.
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
bitmapImage.StreamSource = File.OpenRead(filePath);
bitmapImage.CacheOption = BitmapCacheOption.OnLoad;
bitmapImage.EndInit();
// Convert BitmapImage to byte array.
byte[] imageData = EncodeImage(bitmapImage);
File.WriteAllBytes(outFilePath, imageData);
// Encode with Base64.
string base64String = Convert.ToBase64String(imageData);
// Write to file (for example).
File.WriteAllText(outBase64FilePath, base64String);