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));
}
}

C# , convert gif data to binary array to image

this is related with test instrument but need to more help in C# code.
i did more explain here about my question.
i send command to instrument and i just receive data from instrument.
received data is real format (binary) and i just put in to string variable.
here i captured what's inside in string..
http://i.stack.imgur.com/UcYqV.png
then what i want do is i want this string to convert byte array. because my goal is make png file in my pc. instrument manual said this returned data is gif format but returned real type.'
i believe the problem point is when i convert to byte array,,, there are problem...
does anyone has this kind of experiance,.????
/// below is just send command to instrument that i want " Returns an image of the display in .gif format "
my6705B.WriteString("hcop:sdump:data?", true);
string image_format = my6705B.ReadString();
/// what's inside string image_format ??![i attached screenshot png file. this is what i received from instrument. (manual said this is Returns an image of the display in .gif format)][1] ![png file][2]
http://i.stack.imgur.com/UcYqV.png
/// now here i think i did something wrong,
/// the goal is i want change this return data to gif or png or image file.
/// any solution is ok for me
/// i just try that change this data to byte array and then try to change image file.
/// i think some error here because my code success to convert byte array then create image,,, error
//// i believe that i did something wrong in convert byte array.....
System.Text.UnicodeEncoding encode = new System.Text.UnicodeEncoding();
byte[] byte_array22 = encode.GetBytes(image_format);
MemoryStream ms4 = new MemoryStream(byte_array22);
Image image = Image.FromStream(ms4); //// error point
image.Save(#"C:\Users\Administrator\Desktop\imageTest.png");
i believe that my explain is in comment.
let me explain again that my goal is convert gif data to image file.
instrument give us Returns an image of the display in .gif format.
i received this data to string array. < i dont know this is correct or not but for now i put to string array > then i just want to png or jpg file with this gif data.
please advice,.
Joseph Choi

Please Try ImageFormat Like
image.Save(#"C:\Users\Administrator\Desktop\imageTest.png", System.Drawing.Imaging.ImageFormat.Png);
Update:
byte[] byte_array22 = Encoding.Unicode.GetBytes(image_format);
MemoryStream ms4 = new MemoryStream(byte_array22);
Image image = Image.FromStream(ms4, true, true);
image.Save(#"C:\Users\Administrator\Desktop\imageTest.png",System.Drawing.Imaging.ImageFormat.Png);

Hmm ... here are a couple of methods to transform an image to Base64 format (string), and back.
private 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;
}
}
private Image Base64ToImage(string base64String)
{
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(base64String);
using (var 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;
}
}
You can use them and play with them to see if they suit you.
I'm not sure that taking an image and simply dumping it into string array will help you much.

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.

convert base64 string to image using asp.net c#

I'm using this function to convert base64 to image.
public Image Base64ToImage(string base64String)
{
// Convert Base64 String to byte[]
byte[] imageBytes = Convert.FromBase64String(base64String);
using (var ms = new MemoryStream(imageBytes, 0,imageBytes.Length))
{
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
//Image image = Image.FromStream(ms, true);
Image image = Image.FromStream(ms,true,true);
return image;
}
}
but it is not working. please help me.

I don't thik the ms write call is needed here.
using (var ms = new MemoryStream(imageBytes, 0,imageBytes.Length))
{
// Convert byte[] to Image
ms.Write(imageBytes, 0, imageBytes.Length);
Your are efectively constructing the stream from your byteArray so the ms.Write call will append the data twice in the stream. This might cause issues for your Image object. Either use the default constructor for the stream or delete the Write and test again.
Edit:
Zey deleted his answer but i think he had a good point in there. You might consider dropping the using block as well. My memory might fail me but i think Image objects need the source stream to be kept open. Dispose the Image object when not needed anymore.

How to convert BitmapImage into byte array in silverlight4?

I am trying to convert the BitmapImage into byte array, but not getting the exact solution.
The Image.Save() method is not available in Silverlight Library.
How to fix this?

if you image source is in the project you can use this..
var uri = new Uri("/ReferencedAssembly;component/default.png", UriKind.Relative);
var streamInfo = System.Windows.Application.GetResourceStream(uri);
var stream = streamInfo.Stream;
convert the stream to bytes array..
if image is one some other location
Using httpwebrequest to get image from website to byte[]
Regards