Byte array or matrix to BitMap

Question

I am currently having the following problem: I want to convert a byte array that comes from a file with the following configuration:

Byte1: R color of pixel 0,0.
Byte2: G color of pixel 0,0.
Byte3: B color of pixel 0,0.
Byte4: R color of pixel 0,1.

...
ByteN: R color of pixel n,n.

So what I want to do is convert these bytes into a bitmap without having to set pixel by pixel with bitmap.setPixel because it takes too long.

Any suggestions? Thanks in advance!

How are you determined the width / height if all you have is a byte array? Is it a 2-dimensional array? Is it given to you before hand? — vcsjones
– vcsjones, Commented Jun 7, 2012 at 14:29
Have you seen this? stackoverflow.com/questions/6782489/… Bitmap class has a ctor which uses a byte array directly: msdn.microsoft.com/en-us/library/zy1a2d14 — kol
– kol, Commented Jun 7, 2012 at 14:30
Yes, I do have the width & height of the image. In this case its 1280 x 720. — waclock
– waclock, Commented Jun 7, 2012 at 14:30
Yes Kol I saw those, I tried with using (MemoryStream stream = new MemoryStream(ArregloBytes)) { Bitmap bmp = new Bitmap(stream); frames.Enqueue(bmp); } — waclock
– waclock, Commented Jun 7, 2012 at 14:34

vcsjones · Accepted Answer · 2012-06-07 14:35:53Z

11

If you have the byte[] of the pixels, and the width and height, then you can use BitmapData to write the bytes to the bitmap since you also know the format. Here's an example:

//Your actual bytes
byte[] bytes = {255, 0, 0, 0, 0, 255};
var width = 2;
var height = 1;
//Make sure to clean up resources
var bitmap = new Bitmap(width, height);
var data = bitmap.LockBits(new Rectangle(Point.Empty, bitmap.Size), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb);
Marshal.Copy(bytes, 0, data.Scan0, bytes.Length);
bitmap.UnlockBits(data);

This is a very fast operation.

You will need to import these three namespaces at the top of your C# file, at minimum:

using System.Drawing;
using System.Drawing.Imaging;
using System.Runtime.InteropServices;

answered Jun 7, 2012 at 14:35

vcsjones

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1 Comment

waclock Over a year ago

Thanks for your response, I tried using your code but ImageLockMode, PixelFormat, and Marshal aren't recognized. What extra libraries do I need?

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