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How to load a 16bit (rgb565) bmp into a byte array with c# standard

So I had this bit of code, that works great in my windows c# application or a framework DLL.
private static Icon? LoadSync(string filepath)
{
Stream imageStreamSource = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.Read);
BmpBitmapDecoder decoder = new BmpBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource bitmapSource = decoder.Frames[0];
if (bitmapSource.Format != System.Windows.Media.PixelFormats.Bgr565)
{
Debug.Print($"Image at path `{filepath}` is not RGB565!");
return null;
}
byte[] icon = new byte[bitmapSource.PixelHeight * bitmapSource.PixelWidth * sizeof(short)];
bitmapSource.CopyPixels(icon, bitmapSource.PixelWidth * sizeof(short), 0);
return new Icon() { Width = (ushort)bitmapSource.PixelWidth, Height = (ushort)bitmapSource.PixelHeight, Data = icon };
}
It loads a 16 bit .bmp file into memory, and then gives the pixels to me in the form of a byte array.
However, I encountered a weird compile bug, and my online searches seemed to turn up that it was caused by some odd difference in how a function is declared as an extension method in one instance, but an actual member in another. I forget the details but the proposed solution was to switch to a standard dll from framework. I tried it and it fixed my problem.
But now, reintroducing the above code, I no longer have access to System.Windows.Media.Imaging. So I'm wondering what options I have to be able to accomplish the same thing.
Using the plain old bitmap library, the data is converted to (I think) rgb888 without any option to preserve the format.
If you're wondering why I need a byte array, I'm sending the data on to an arduino with a screen.

I have never done exactly what you're trying to do, but I did recently have to work with images in some C# code. I added the System.Drawing NuGet package and made use of the Image class. This might be a help: https://learn.microsoft.com/en-us/dotnet/api/system.drawing.image?view=windowsdesktop-5.0

Raspberry Pi and framebuffer input with mono

I'm trying to render a bitmap in Memory using mono. This image should be displayed on Adafruits 2.8" touch TFT (320*240). The Programm is developed with Visual Studio 2013 Community Edition. I want to host a ASP.NET Web Api and Show
some data on the Display. The ASP.NET part is working fine and the image is rendered. My idea was to write the Image to the framebuffer Input, but doing this I get an Exception saying that file is to large. I'm just writing raw data without BMP Header. Has someone managed doing this? Maybe creation of image is
wrong.
It seems as something is happening because the display changes and I can see white areas which might be from my image.
I don't want to use any extra libraries to keep it simple. So my idea is to use FBI directly. Does anyone know this problem and the solution?
Here is some of my code:
using (Bitmap bmp = new Bitmap(240, 320, PixelFormat.Format16bppRgb555))
{
[...]
Byte[] image = null;
using(MemoryStream memoryStream = new MemoryStream())
{
bitmap.Save(memoryStream, ImageFormat.Bmp);
Byte[] imageTemp = memoryStream.GetBuffer();
//Remove BMP header
image = new Byte[imageTemp.Length - 54];
Buffer.BlockCopy(imageTemp, 54, image, 0, image.Length);
//153600 byte
using (FileStream fb1 = new FileStream("/dev/fb1", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
{
fb1.Write(image, 0, image.Length);
fb1.Close();
}
}
}

Take a look at http://computerstruggles.blogspot.de/2013/02/how-to-program-directfb-in-c-on.html - the idea is to install the directfb library and use it from C# with PInvoke. The blog's author uses a mini wrapper in C to make using it even easier. BTW why don't you like to install additional libraries and to profit from the work others have done for you?

You may be running out of memory when the MemoryStream reallocates memory. When it needs to grow, it doubles in size. With this large of a write, the internal buffer is probably exceeding available memory. See Why does C# memory stream reserve so much memory? for more information.

Resize image on the fly in .net and c#

I'm looking for a way to resize images without saving them on the server. The ways that i have found includes a controller file and such.
Is there a way to get the image from the stream, resize it and add it to the response?

Check out ImageResizer - it's a suite of NuGet packages designed for this exact purpose.
It runs eBay in Denmark, MSN Olympics, and a few other big sites.
Dynamic image processing can be done safely and efficiently, but not in a sane amount of code. It's trickier than it appears.

I wouldn't recommend this but you can do next thing:
using (Image img = Image.FromStream(originalImage))
{
using (Bitmap bitmap = new Bitmap(img, width, height))
{
bitmap.Save(outputStream, ImageFormat.Jpeg);
}
}
Be aware that this could cause OutOfMemoryException.

WinRT image handling

A friend and I spent the better part of last night nearly tearing our hair out trying to work with some images in a metro app. We got images into the app with the share charm, and then I wanted to do some other work with them, cropping the images and saving them back into the appdata folder. This proved extremely frustrating.
My question, at the end of all this, is going to be "What's the proper way of doing this, without feeling like I'm hammering together a bunch of mismatched jigsaw puzzle pieces?"
When sharing multiple images with the app, they come in as a list of Windows.Storage.StorageFiles. Here's some code used to handle that.
var storageItems = await _shareOperation.Data.GetStorageItemsAsync();
foreach (StorageFile item in storageItems)
{
var stream = await item.OpenReadAsync();
var properties = await item.Properties.GetImagePropertiesAsync();
var image = new WriteableBitmap((Int32)properties.Width, (Int32)properties.Height);
image.SetSource(stream);
images.Add(image);
}
Some searching online has indicated that currently, a Windows.UI.Xaml.Media.Imaging.WriteableBitmap is the only thing capable of letting you access the pixel data in the image. This question includes a helpful answer full of extension methods for saving images to a file, so we used those.
Our problems were the worst when I tried opening the files again later. I did something similar to before:
var files = await ApplicationData.Current.LocalFolder.GetFilesAsync();
foreach (var file in files)
{
var fileStream = await file.OpenReadAsync();
var properties = await file.Properties.GetImagePropertiesAsync();
var bitmap = new WriteableBitmap((Int32)properties.Width, (Int32)properties.Height);
bitmap.SetSource(fileStream);
System.IO.Stream stream = bitmap.PixelBuffer.AsStream();
Here comes a problem. How long is this stream, if I want the bytes out of it?
// CRASH! Length isn't supported on an IRandomAccessStream.
var pixels = new byte[fileStream.Length];
Ok try again.
var pixels = new byte[stream.Length];
This works, except... if the image is compressed, the stream is shorter than you would expect, so you will eventually get an out of bounds exception. For now pretend it's an uncompressed bitmap.
await _stream.ReadAsync(pixels, 0, pixels.Length);
Well guess what. Even though I said bitmap.SetSource(fileStream); in order to read in the data, my byte array is still full of zeroes. I have no idea why. If I pass this same bitmap into a my UI through the sample data group, the image shows up just fine. So it has clearly got the pixel data in that bitmap somewhere, but I can't read it out of bitmap.PixelBuffer? Why not?
Finally, here's what ended up actually working.
var decoder = await BitmapDecoder.CreateAsync(BitmapDecoder.PngDecoderId, fileStream);
var data = await decoder.GetPixelDataAsync();
var bytes = data.DetachPixelData();
/* process my data, finally */
} // end of that foreach I started a while ago
So now I have by image data, but I still have a big problem. In order to do anything with it, I have to make assumptions about its format. I have no idea whether it's rgba, rgb, abgr, bgra, whatever they can be. If I guess wrong my processing just fails. I've had dozens of test runs spit out zero byte and corrupted images, upside down images (???), wrong colors, etc. I would have expected to find some of this info in the properties that I got from calling await file.Properties.GetImagePropertiesAsync();, but no luck. That only contains the image width and height, plus some other useless things. Minimal documentation here.
So, why is this process so painful? Is this just reflecting the immaturity of the libraries right now, and can I expect it to get better? Or is there already some standard way of doing this? I wish it were as easy as in System.Drawing. That gave you all the data you ever needed, and happily loaded any image type correctly, without making you deal with streams yourself.

From what I have seen - when you are planning on loading the WriteableBitmap with a stream - you don't need to check the image dimensions - just do new WriteableBitmap(1,1), then call SetSource().
Not sure why you were thinking var pixels = new byte[fileStream.Length]; would work, since the fileStream has the compressed image bytes and not a pixel array.
You might need to seek to the beginning of the stream to get the pixels array:
var pixelStream = pixelBuffer.AsStream();
var bytes = new byte[this.pixelStream.Length];
this.pixelStream.Seek(0, SeekOrigin.Begin);
this.pixelStream.Read(bytes, 0, Bytes.Length);
I had started working on a WinRT port of WriteableBitmapEx - maybe it could help you: http://bit.ly/WriteableBitmapExWinRT. I have not tested it well and it is based on an older version of WBX, but it is fairly complete in terms of feature support. Might be a tad slower than it is possible too.

C# - How to use Jpeg to compress images and send to a server?

I want to build a Screen Sharing program in C#.(with TCP)
I sniffed around the web and found out that the most efficient way to do it is by sending alot of screenshots from the client to the server.
The point is - how can I compress a Bitmap to Jpeg - receive it on the server and decompress again to Bitmap (so I can show it in a form) ?
I've tried using the JpegBitmapEncoder with no luck, here's my code:
Bitmap screen = TakeScreenshot();
MemoryStream ms = new MemoryStream();
byte[] Bytes = BmpToBytes_Unsafe(screen);
ms.Write(Bytes, 0, Bytes.Length);
Jpeg = new JpegBitmapEncoder();
Jpeg.Frames.Add(BitmapFrame.Create(ms));
Jpeg.QualityLevel = 40;
Jpeg.Save(ms);
BinaryReader br = new BinaryReader(ms);
SendMessage(br.ReadBytes((int)ms.Length));
It throws an NotSupportedException at Jpeg.Frames.Add(BitmapFrame.Create(ms));
No imaging component suitable to complete this operation was found.
So I need a way to convert a Bitmap to Jpeg, then to byte[], then send it over TCP.
And on the other end, do the exact opposite. Any suggestions ?
Thank you.

JPEG was designed for photographs, not for screen captures. Also, most of the screen doesn't change so better to just send the changed portions and only a full screen when much of the screen has changed.
Unless you're just doing this for fun, you are going about this all wrong. VNC has been doing this for years and the source code is free so you could look to see how that's done.