Pixel Programming continued

Question

I have got a byte array of pixels in BGR order and I want to create an image out of it in C#. Can anyone offer code or advice?

Answer 1

Something to the effect of (not-tested)

        private Bitmap createImage(int width, int height, byte[] image)
        {
            int index = 0;
            byte r, g, b;
            Bitmap bmp = new Bitmap(width, height);
            for (y as int = 0; y < height; y++)
            {                
                for (x as int = 0; x < width; x++)
                {
                    b = image[y * width + index];
                    g = image[y * width + index + 1];
                    r = image[y * width + index + 2];
                    bmp.SetPixel(x, y, Color.FromArgb(255, r, g, b));
                    index += 3;
                }                
            }
            return bmp;
        }

Answer 2

The Bitmap(int width, int height, int stride, PixelFormat format, IntPtr scan0) constructor for the Bitmap class might be helpful. It depends on how the data is stored in the array, of course.

Answer 3

You might need something like this :

public static Bitmap TransformBGRArrayToBitmap(byte[] inputValues, int Width, int Height, int Stride)
{
    Bitmap output = new Bitmap(Width, Height, System.Drawing.Imaging.PixelFormat.Format8bppIndexed);

    // Lock the bitmap's bits.  
    Rectangle rect = new Rectangle(0, 0, Width, Height);
    BitmapData outputData = output.LockBits(rect, System.Drawing.Imaging.ImageLockMode.WriteOnly, output.PixelFormat);

    // Get the address of the first line.
    IntPtr outputPtr = outputData.Scan0;

    // Declare an array to hold the bytes of the bitmap.
    byte[] outputValues = new byte[outputData.Stride * output.Height];
    int inputBytesPP = (1 * Stride) / Width;
    int outputBytesBPP = (1 * outputData.Stride) / output.Width;

    // Copy the RGB values into the array.
    for (int inputByte = 0, outputByte = 0; inputByte < inputValues.Length; inputByte += inputBytesPP, outputByte += outputBytesBPP)
    {
        //The logic inside this loop transforms a 32 bit ARGB Bitmap into an 8 bit indexed Bitmap
        //So you will have to replace it
        /*byte pixel = 0x00;
        if (inputValues[inputByte] > 0x7F)
        {
            if (inputValues[inputByte + 1] > 0x7F)
                pixel |= 0x01;
            if (inputValues[inputByte + 2] > 0x7F)
                pixel |= 0x02;
            if (inputValues[inputByte + 3] > 0x7F)
                pixel |= 0x04;
            if ((inputValues[inputByte + 1] & 0x7F) > 0x3F)
                pixel |= 0x02;
            if ((inputValues[inputByte + 2] & 0x7F) > 0x3F)
                pixel |= 0x04;
            if ((inputValues[inputByte + 3] & 0x7F) > 0x3F)
                pixel |= 0x08;
        }
        else
            pixel = 0x10;
        outputValues[outputByte] = pixel;*/
    }
    System.Runtime.InteropServices.Marshal.Copy(outputValues, 0, outputPtr, outputValues.Length);
    output.UnlockBits(outputData);
    return output;
}