Question

I have hex data and I want to convert it to 200×200 pixel grayscale picture, but I can’t find a way to do it.

Can anyone please show me a way or give me a resource to solve this problem??

Answer 1

For what you have written (too few) you could create Bitmap bmp = new Bitmap(200,200).
Then you could use bmp.SetPixel(x,y,color) according to your text data.

UPDATE:
Assuming a lot of things:

• you have a hexstr containing hex data representing your bmp
• hexstr is made of two chars groups (hex data)
• every hex data group is 2 or 6 chars long (2 chars if hex val is already a greyscale val, 6 chars if you have a RGB value to convert to grayscale)

SECOND UPDATE:
Your file contanins 16×2450=39200 pixel, so your image cannot be 200×200. I assume it’s 200×192.
This code works, even if I don’t understand what image represents…

You can try this:

public Form1()
{
    InitializeComponent();
    string hexstr = FileToHexStr(path_to_file);
    pictureBox1.Image = ConvertToBmp(hexstr, 200, 196, true);
}

private string FileToHexStr(string filename)
{
    StringBuilder sb = new StringBuilder();
    string[] f = File.ReadAllLines(filename);
    foreach (string s in f) sb.Append(s.Trim().Replace(" ", ""));
    return sb.ToString();
}

private byte[] StringToByteArray(string hex)
{
    return Enumerable.Range(0, hex.Length)
                     .Where(x => x % 2 == 0)
                     .Select(x => System.Convert.ToByte(hex.Substring(x, 2), 16))
                     .ToArray();
}

private Bitmap ConvertToBmp(string hexstr, int width, int height, bool isGrayScaleString)
{
    /// If hexstr is a color bitmap I assume that a single pixel
    /// must be 3 values long (one for R, one for G, one for B);
    /// if not, then every hex value is a pixel
    int bpp = isGrayScaleString ? 1 : 3;
    byte[] hexarr = StringToByteArray(hexstr);
    // Check if string is correct
    if (hexarr.Length != (width * height * bpp)) return null;

    Bitmap bmp = new Bitmap(width, height);
    int index = 0;
    for (int i = 0; i < hexarr.Length; i +=  bpp)
    {
        int luma = (int)(isGrayScaleString ?
            hexarr[index] :
            // Formula to convert from RGB to Grayscale
            // <see>http://www.bobpowell.net/grayscale.htm</see>
            0.3 * hexarr[i] + 0.59 * hexarr[i + 1] + 0.11 * hexarr[i + 2]);
        Color c = Color.FromArgb(luma, luma, luma);
        bmp.SetPixel(index % width, index / width, c);
        index++;
    }
    return bmp;
}