Develop Reference

Byte Array to Image using C# in Xamarin

I've been searching for the past few days but did not manage to find a solution for my problem. I am currently working on a xamarin Android app. I want to display an image by using the byte array column from by database. I am using another program to find the byte array of a specific photo and after that I insert manually its value in the byte array column from my principal project.
This is my code where I am trying to reproduce the image:
Android.Graphics.Bitmap bitmap=BitmapFactory.DecodeByteArray(currentexercis.image, 0, currentexercis.image.Length);
viewHolder.exercis_photo.SetImageBitmap(bitmap);
Currentexercis.image represents the byte array from my database, and its value seems to be OK, however every time bitmap is null.
This is the code from my other program where I convert the image into bytearray:
Image img = Image.FromFile(opendlg.FileName);
MemoryStream ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
dbpicEntities1 db = new dbpicEntities1();
db.MyPictures.Add(new MyPicture() { FileName=fileName, Data = ms.ToArray() });
db.SaveChanges();
MessageBox.Show("success");

I think you should use like this.
byte [] imageArray // is your data
MemoryStream mStream = new MemorySteram ();
mStream.write(imageArray,0,imageArray.Length);
Image img = Image.FromStream(mStream);
img.save(filelocation);
Bitmap bitmapimg = BitmapFactory.BitmapFactory.DecodeStream(mStream);
// if you want to use Bitmap

Byte Array to Image using C# in Xamarin
There are some third-party library which implements this feature quite well like Picasso or Glide.
For Glide, there is official document shows how to use it in Xamarin.Android project: Binding a .JAR.
Or you could directly use it from the nuget package:
Then you can code for example like this:
Glide.With(context)
.Load(imageBytes)
.Apply(RequestOptions.CircleCropTransform())
.Into(imageView);

convert to byteArray
byte[] imgdata = System.IO.File.ReadAllBytes(pathToImage);
convert byte array to bitmap
private void OnGetMemberAvatarCompleted(byte[] avatarBytes)
{
var avatarImageView = FindViewById<ImageView>(Resource.Id.memberProfile_avatar);
if (avatarImageView != null)
{
var imageBitmap = BitmapFactory.DecodeByteArray(avatarBytes, 0,avatarBytes.Length);
RunOnUiThread(() => avatarImageView.SetImageBitmap(imageBitmap));
}
}

Getting error from the inkcanvase base 64 string

Hello we are using InkCanvas control on the wpf page. And we are saving Base64String string in the database. See code
private void submitButtonsCommand_Event(object sender)
{
byte[] sigByte;
InkCanvas icSignature = sender as InkCanvas;
using (var memoryStream = new MemoryStream())
{
icSignature.Strokes.Save(memoryStream);
sigByte = memoryStream.ToArray();
}
ServiceCallReportSignatureModel.SigCustomerSignature = Convert.ToBase64String(sigByte);
UpdateRecord();
}
And when we are retrieving data from the database and converting into the FromBase64String and after that when we creating image then we are getting the error.
public Image LoadImage(base64string)
{
//data:image/gif;base64,
//this image is a single pixel (black)
byte[] bytes = Convert.FromBase64String(base64string);
Image image;
using (MemoryStream ms = new MemoryStream(bytes))
{
image = Image.FromStream(ms);
}
return image;
}
I don't know why this is occurring. Please help me find out the error.
Our base64 string is : "AIwBAwxIEEWfARsCAAb/RjURAACAPx8JEQAAAAAAAPA/Cmwsh/EgR4kP+Etw/ojDWG7NZ8OZQxBN5otEzmU1mk04I7DnATcLHomzzUbxw/h3Dtp16yhlTQ2UsoTQh+uE64XgjsN6Js2UZpAZmFpmaZTKzzKZ4ctFmw3Mlmm0Bw9h/DtpTPKu79CYgm+VJqA="
Actually we are taking signature from the ink canvas control and we want to display in the pdf when we need. So we want create image from the base 64 data but we are getting the error.

The StrokeCollection.Save(Stream) method does not save a bitmap. Instead,
The Save method saves the StrokeCollection as Ink Serialized Format (ISF).
You can restore the saved StrokeCollection by passing a Stream with the saved data to the StrokeCollection(Stream) constructor.

Conversion of a Bitmap to Pixel Array for Microsoft OCR C#

I'm working with Microsoft's OCR library and am having problems converting the BitmapImage to a pixel array.
I'm making this application for Windows Phone 8, and WriteableBitmap.PixelBuffer.ToArray() isn't an option so I have a static function that'll change a normal BitmapImage into a byte array to feed into the OCR engine.
Well, every time I feed it in the application crashes. What's wrong here?
Here is my static class with the bitmap converter
public static class ByteArrayChange
{
public static byte[] ConvertToBytes(this BitmapImage bitmapImage)
{
byte[] data = null;
using (MemoryStream stream = new MemoryStream())
{
WriteableBitmap wBitmap = new WriteableBitmap(bitmapImage);
wBitmap.SaveJpeg(stream, wBitmap.PixelWidth, wBitmap.PixelHeight, 0, 100);
stream.Seek(0, SeekOrigin.Begin);
data = stream.GetBuffer();
}
return data;
}
}
Here is the piece of code in the OCR method that's causing the application to crash.
byte[] pa = ByteArrayChange.ConvertToBytes(bitmap);
//Here Is he problem
var ocrResult = await ocrEngine.RecognizeAsync((uint)bitmap.PixelHeight, (uint)bitmap.PixelWidth, pa);
What am I doing wrong here?
Thanks!

You're saving your image as JPEG, but I'm fairly certain that OCR library accept RGB/BGRA as an input.
So why don't you use Pixels property? It represents image as BGRA array, so the only thing you need is to convert it to byte[] array.

Image/ImageSource/Interop Image to bytearray

I'm developing a control where user can set an image and i want this this to be as user friendly as possible - so support for copy & paste, drag & drop.
I've got this part working using IDataObjects, testing for fileformats of FileDrop, FileContents (eg from outlook), and bitmap eg:
private void GetImageFromIDataObject(IDataObject myIDO)
{
string[] dataformats = myIDO.GetFormats();
Boolean GotImage = false;
foreach (string df in dataformats)
{
if (df == DataFormats.FileDrop)
{
// code here
}
if (df == DataFormats.Bitmap)
{
// Source of my problem here... this gets & displays image but
// how do I then convert from here ?
ImageSource myIS = Utilities.MyImaging.ImageFromClipboardDib();
ImgPerson.Source = myIS;
}
}
}
The ImageFromClipboard code is Thomas Levesque's as referenced in the answer to this SO question wpf InteropBitmap to bitmap
http://www.thomaslevesque.com/2009/02/05/wpf-paste-an-image-from-the-clipboard/
No matter how I get the image onto ImgPerson, this part is working fine; image displays nicely.
When user presses save I need to convert the image to a bytearray and send to a WCF server which will save to server - as in, reconstruct the bytearray into an image and save it in a folder.
For all formats of drag & drop, copy & paste the image is some form of System.Windows.Media.Imaging.BitmapImage.
Except for those involving the clipboard which using Thomas's code becomes System.Windows.Media.Imaging.BitmapFrameDecode.
If I avoid Thomas's code and use:
BitmapSource myBS = Clipboard.GetImage();
ImgPerson.Source = myBS;
I get a System.Windows.Interop.InteropBitmap.
I can't figure out how to work with these; to get them into a bytearray so I can pass to WCF for reconstruction and saving to folder.

Try this piece of code
public byte[] ImageToBytes(BitmapImage imgSource)
{
MemoryStream objMS = new MemoryStream();
PngBitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(imgSource));
encoder.Save(objMS);
return objMS.GetBuffer();
}
You can also use JpegBitmapEncoder, BmpBitmapEncoder based on your requirements.
byte[] arr = ImageToBytes(ImgPerson.Source as BitmapImage);

I can't believe I didn't see this SO question but the this is essentially the same as my question:
WPF: System.Windows.Interop.InteropBitmap to System.Drawing.Bitmap
The answer being:
BitmapSource bmpSource = msg.ThumbnailSource as BitmapSource;
MemoryStream ms = new MemoryStream();
BitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bmpSource));
encoder.Save(ms);
ms.Seek(0, SeekOrigin.Begin);
System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(ms);
So similar in execution to Nitesh's answer but crucially, works with an inter-op bitmap.

Convert System.Drawing.Image to System.Windows.Controls.Image?

Is there a way in C# to do this conversion and back?
I have a WPF app which has a Image control. I'm trying to save the image in that control to a SQL Database.
In my Entity Model, the datatype of the picture column in my database is a byte[]. So I found a method to convert a System.Drawing.Image to a byte[] and back. But I haven't found a method to convert from System.Windows.Controls.Image to a byte[].
So that's why I now need to do the above conversion.

If you have a byte array that represents a file that WPF can decode (bmp, jpg, gif, png, tif, ico), you can do the following:
BitmapSource LoadImage(Byte[] imageData)
{
using (MemoryStream ms = new MemoryStream(imageData))
{
var decoder = BitmapDecoder.Create(ms,
BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.OnLoad);
return decoder.Frames[0];
}
}
Likewise, to convert it back, you can do the following:
byte[] SaveImage(BitmapSource bitmap)
{
using (MemoryStream ms = new MemoryStream())
{
var encoder = new BmpBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(bitmap));
encoder.Save(ms);
return ms.GetBuffer();
}
}

Well, one is an image and one is a control that shows an image, so I don't think that there's a conversion between the two. But, you could set the Source of the ...Controls.Image to be your ...Drawing.Image.
Edit based on update
Does this do what you need - http://msdn.microsoft.com/en-us/library/ms233764%28VS.100%29.aspx