Convert a string to a bitmap in c#

Question

I want to convert a string into a bitmap or something I can show in a pixelbox.

My string looks like this:

string rxstring = "010010010020020020030030030040040040050050050060060060070070070080080080090090090100100100110110110120120120130130130140140140150150150160160160“

It is no problem to erase the RGB code in the string

("01002003004005060070080090100110120130140150160");

I only need it to show, the is not important [sic]

IDE: VS2010 C#

str "010010010020020020030030030040040040050050050060060060070070070080080080090090090100100100110110110120120120130130130140140140150150150160160160\r" string this is the information for the debugger. ist a string filled with chars in ascci formart — LFS96, Nov 27 '13 at 14:16
@FabianHarmsen, I got that. I'm asking if the string is in Base64 coming from the device. — Mike Perrenoud, Nov 27 '13 at 14:16
i don't know. how the arduino une send it, and i have no changes to set config how the datas will be send. http://arduino.cc/en/Serial/Print this is the refferns to the sending funtion on my bord — LFS96, Nov 27 '13 at 14:22
i have look a littel bit i dont think that i send base64 strings, i think he use 1 byte per char — LFS96, Nov 27 '13 at 14:30

score 8 · Answer 1 · edited Jun 20 '20 at 09:12

8

I'm afraid the data you are getting is not a meaningful image. If you split the data into groups of three. You get the following:

If you look at that data there's no way you can convert this to an image that would actually mean something to us. It would be a collection of 48 pixels. Containing a sort of gradient like image (since the numbers below follow a pattern that is constantly increasing.

We would need more information to debug this. (Like what component is providing the data etc.)

Update This is what I get when I convert your data to pixels (take in account i've enlarged every pixel to 16x16)

Result when assembling the data

edited Jun 20 '20 at 09:12

Community

1
1

answered Nov 27 '13 at 14:35

woutervs

1,500
12
28

Also converting the above string to text gives you: (((222<< – woutervs Nov 27 '13 at 14:42
it is a piture with 4x4 Pixel witch want to show in gray on a pixelbox i know you cann't see much but in some time there will be more pixel then i get better termal camara – LFS96 Nov 27 '13 at 14:52
I've updated my answer with an upscaled image of the result of your data. This should be 16 times smaller, thus invisible for the naked eye to see. Are you sure your arduino is sending the right data? – woutervs Nov 27 '13 at 15:18

score 1 · Answer 2 · edited Sep 08 '17 at 11:10

Try converting the string to a byte array and loading it into a memory stream. Once in the stream, you should be able to convert to an image.

List<byte> splitBytes = new List<byte>();            
string byteString = "";

foreach (var chr in testString)
{
    byteString += chr;

    if (byteString.Length == 3)
    {
       splitBytes.Add(Convert.ToByte(byteString));
       byteString = "";
    }
}

if (byteString != "")
    splitBytes.AddRange(Encoding.ASCII.GetBytes(byteString));

using (var ms = new MemoryStream(splitBytes.ToArray()))
{
    var img = System.Drawing.Image.FromStream(ms);

    //do something with image.
}

EDIT: Added updated code. This was tested by loading an image of my own and converting the bytes into a string, then converting them back into a byte array using the above code and I successfully loaded the image from a string.

string testString = "255216255224000016074070073070000001001001000096000096000000255225000104069120105102000000077077000042000000000008000004001026000005000000000001000000000062001027000005000000000001000000000070001040000003000000000001000002000000001049000002000000000018000000000078000000000000000000000096000000000001000000000096000000000001080097105110116046078069084032118051046053046049049000255219000067000002001001002001001002002002002002002002002003005003003003003003006004004003005007006007007007006007007008009011009008008010008007007010013010010011012012012012007009014015013012014011012012012255219000067001002002002003003003006003003006012008007008012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012012255192000017008000004000004003001034000002017001003017001255196000031000000001005001001001001001001000000000000000000000000001002003004005006007008009010011255196000181016000002001003003002004003005005004004000000001125001002003000004017005018033049065006019081097007034113020050129145161008035066177193021082209240036051098114130009010022023024025026037038039040041042052053054055056057058067068069070071072073074083084085086087088089090099100101102103104105106115116117118119120121122131132133134135136137138146147148149150151152153154162163164165166167168169170178179180181182183184185186194195196197198199200201202210211212213214215216217218225226227228229230231232233234241242243244245246247248249250255196000031001000003001001001001001001001001001000000000000000000001002003004005006007008009010011255196000181017000002001002004004003004007005004004000001002119000001002003017004005033049006018065081007097113019034050129008020066145161177193009035051082240021098114209010022036052225037241023024025026038039040041042053054055056057058067068069070071072073074083084085086087088089090099100101102103104105106115116117118119120121122130131132133134135136137138146147148149150151152153154162163164165166167168169170178179180181182183184185186194195196197198199200201202210211212213214215216217218226227228229230231232233234242243244245246247248249250255218000012003001000002017003017000063000252225248089251085248195193031007060033030133127054137107121166121143107103121116176043069052182202085076167111238224143056234193152252204073040162128063255217";

EDIT: Added a sample string of the image I used to test the above code.

This would work, but still be a meaningless image with his data. — woutervs, Nov 27 '13 at 14:37
From what I can tell, converting an images byte array into a string is what is corrupting the data. Theoretically, the above code should work, but upon testing, the string itself when converted into a byte array isn't a valid byte array that the Image class can load. — Loren Shaw, Nov 27 '13 at 15:07
If your string is a valid representation of a byte array, it should load. — Loren Shaw, Nov 27 '13 at 15:41

Loren Shaw · Accepted Answer · 2013-11-27T16:29:45.160

Upon continuing review, I realized that the string your getting isn't a byte array. This creates a square Bitmap and lets you set the values pixel by pixel.

List<string> splitBytes = new List<string>();
string byteString = "";
foreach (var chr in rsstring)
        {
            byteString += chr;

            if (byteString.Length == 3)
            {
                splitBytes.Add(byteString);
                byteString = "";
            }
        }

        var pixelCount = splitBytes.Count / 3;
        var numRows = pixelCount / 4;
        var numCols = pixelCount / 4;

        System.Drawing.Bitmap map = new System.Drawing.Bitmap(numRows, numCols);

        var curPixel = 0;
        for (int y = 0; y < numCols; y++)
        {
            for (int x = 0; x < numRows; x++ )
            {
                map.SetPixel(x, y, System.Drawing.Color.FromArgb(
                    Convert.ToInt32(splitBytes[curPixel * 3]),
                    Convert.ToInt32(splitBytes[curPixel * 3 + 1]),
                    Convert.ToInt32(splitBytes[curPixel * 3 + 2])));

                curPixel++;
            }
        }
        //Do something with image

EDIT: Made corrections to the row/col iterations to match the image shown above.

This assumes that the image you send is always a square, and will treat it as such. — Loren Shaw, Nov 27 '13 at 16:24
Be aware that the larger, more complex the image becomes, the longer this code will take to execute. — Loren Shaw, Nov 29 '13 at 13:45
i know. in the next stepp i will try to split stringsan then ich will try to use a faster way to create my string — LFS96, Dec 03 '13 at 06:53

Convert a string to a bitmap in c#

3 Answers3

Linked