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));
}
}

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.

Getting a Byte Array from the audio file saved by Media.RecordSoundAction

I have a file that is created using
var recordIntent = new Intent(MediaStore.Audio.Media.RecordSoundAction);
I have no problems retrieving the URI of this file. And I can play it back using MediaPlayer without any difficulties.
However, I would like to send this as a response to my webAPI, and am looking at a way to convert the Audio File represented by this URI to a byte array that I can convert to JSON.
With an image file i can do something like
Bitmap bitmap = MediaStore.Images.Media.GetBitmap(ContentResolver, responseUri);
bitmap.Compress(Bitmap.CompressFormat.Png, 0, stream);
byte[] bitmapData = stream.ToArray();
Is there a similar way I can retrieve the Byte Array data from my audio URI?
edit:
formatting of Audio URI.
responseUri = {content://media/external/audio/media/21}

Taken from a ton of different SO answers, and a little bit of extra conversion for mono from Java I came up with these results.
public String GetRealPathFromUri(Uri contentUri){
String[] proj = {MediaStore.Audio.AudioColumns.Data};
ICursor cursor = ManagedQuery(contentUri, proj, null, null, null);
int column_index = cursor.GetColumnIndex(MediaStore.Audio.AudioColumns.Data);
cursor.MoveToFirst();
return cursor.GetString(column_index);
}
var responseRealPath = GetRealPathFromUri(responseUri);
var getBytes = System.IO.File.ReadAllBytes(responseRealPath);
var responseBase = Convert.ToBase64String(getBytes);

convert image to byte[] c# and get image back in android

I have the following code in c# which convert image to the byte[]
MemoryStream memory = new MemoryStream();
bitmap.Save(memory, System.Drawing.Imaging.ImageFormat.Jpeg);
now i want to get the image back in the android, what should i do ?

Im not really sure what your problem is as you haven't answered anyones question but if you just want to make a bitmap out of a byte array this how to do it
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, opt);

Convert ByteArray to Base64 string in C#. Then Convert Base64 string to ByteArray in android an do everything you want. In this method you can work with any object type in addition to bitmap.

Load a byte[] into an Image at Runtime

I have a byte[] that is represented by an Image. I am downloading this Image via a WebClient. When the WebClient has downloaded the picture and I reference it using its URL, I get a byte[]. My question is, how do I load a byte[] into an Image element in WPF? Thank you.
Note: This is complementary to the question I asked here: Generate Image at Runtime. I cannot seem to get that approach to work, so I am trying a different approach.

Create a BitmapImage from the MemoryStream as below:
MemoryStream byteStream = new MemoryStream(bytes);
BitmapImage image = new BitmapImage();
image.BeginInit();
image.StreamSource = byteStream;
image.EndInit();
And in XAML you can create an Image control and set the above image as the Source property.

You can use a BitmapImage, and sets its StreamSource to a stream containing the binary data. If you want to make a stream from a byte[], use a MemoryStream:
MemoryStream stream = new MemoryStream(bytes);

In .Net framework 4.0
using System.Drawing;
using System.Web;
private Image GetImageFile(HttpPostedFileBase postedFile)
{
if (postedFile == null) return null;
return Image.FromStream(postedFile.InputStream);
}

One way that I figured out how to do it so that it was both fast and thread safe was the following:
var imgBytes = value as byte[];
if (imgBytes == null)
return null;
using (var stream = new MemoryStream(imgBytes))
return BitmapFrame.Create(stream,BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
I threw that into a converter for my WPF application after running the images as Varbinary from the DB.