Grt bytes array from HICON for sending to C# client and printing on listview

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Hi, I need to get bytes from HICON handle to send it from server(C++) to client(C#) but I do not know how.

i need to send the byte with
send(socket,(CHAR*)&Byte_to_send,sizeof(Byte_to_send);

Byte_to_send should be the bytes associated to HICON of each windows application, and

I've got it in this way:
HICON icon = (HICON)GetClassLong(hWnd, GCL_HICON);

What I have tried:

SIDE C++ SERVER:

HICON icon = (HICON)GetClassLong(hWnd, GCL_HICON);

ICONINFO oIconInfo;
if(::GetIconInfo(icon, &oIconInfo)==true){
cout <<"Success!"<<endl;
send(newConnection,(CHAR*)&oIconInfo,sizeof(oIconInfo),NULL);
}else{
cout <<"Failure!"<<endl;
}

Now I have to convert the stream of byte read from my client(this is made in c#) that I have received from my c++ server, and convert the array of bytes to an Image.
So I have tried to do this:

SIDE C# CLIENT:

byte[] buffer = new byte[1500];
sck.Receive(buffer);
TypeConverter tc = TypeDescriptor.GetConverter(typeof(Bitmap));
Bitmap bitmap1 = (Bitmap)tc.ConvertFrom(buffer);
imageList1.Images.Add(bitmap1);

When I try this, I receive an error at this line:

Bitmap bitmap1 = (Bitmap)tc.ConvertFrom(buffer);

This is the message error that I have received:

Unhandled exception of the 'System.ArgumentException' type System.Drawing.dll
Additional information: Invalid parameter.

I have also tried:

MemoryStream ms = new MemoryStream(buffer);
Bitmap bmp;
bmp = new Bitmap(ms);

and this other:

ImageConverter ic = new ImageConverter();
System.Drawing.Image img = (System.Drawing.Image)ic.ConvertFrom(buffer);
Bitmap bitmap1 = new Bitmap(img);

but I have received the same error message.

Posted 5-Apr-17 23:06pm

Member 12891988

Updated 5-Apr-17 23:43pm

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Jochen Arndt · Answer 1 · 2017-04-05T23:43:00

Solution 1

The C++ portion is not implementing what I have suggested at Get bytes from HICON to sending via socket from server to client[^]. The ICONINFO structure does not contain the image data but only a bitmap handle. You have to send the image information and data.

Untested from scratch:

ICONINFO oIconInfo;
if (::GetIconInfo(icon, &oIconInfo))
{
    // EDIT: Modified code to create a DIB
    HBITMAP hDib = oIconInfo.hbmColor;

    // Get bitmap info for colour mask
    DIBSECTION ds;
    int nSizeDS = ::GetObject(hDib, sizeof(ds), &ds);
    // EDIT: is not a DIB: Create one
    if (sizeof(ds) != nSizeDS)
    {
        hDib = (HBITMAP)::CopyImage(oIconInfo.hbmColor, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION);
        nSizeDS = ::GetObject(hDib, sizeof(ds), &ds);
    }
    // Send the DIBSECTION
    send(newConnection, &ds, sizeof(ds), NULL);
    // Send raw bitmap data
    send(newConnection, ds.dsBm.bmBits, ds.dsBmih.biSizeImage, NULL);
    // EDIT: Release bitmap when a DIB copy has been created
    if (hDib && hDib != oIconInfo.hbmColor)
        ::DeleteObject(hDib);
}

On the C# receiving site receive the DIBSECTION structure first. Then receive the raw data into an buffer of size ds.dsBmih.biSizeImage. Finally create the bitmap using the Bitmap Constructor (Int32, Int32, Int32, PixelFormat, IntPtr) (System.Drawing)[^].
The parameters are:
width = ds.dsBm.bmWidth or ds.dsBmih.biWidth
height = ds.dsBm.bmHeight or ds.dsBmih.biHeight
stride = ds.dsBm.bmWidthBytes;
format = depends on ds.dsBm.bmBitsPixel; usually Format24bppRgb
scan0 = the raw data buffer

Posted 5-Apr-17 23:43pm

Jochen Arndt

Updated 6-Apr-17 0:39am

v2

Comments

Member 12891988 6-Apr-17 6:03am

Thanks a lot Jochen I will try.

Member 12891988 6-Apr-17 6:25am

When I try that piece of code,the if (sizeof(ds) == nSizeDS) condition, isn't ever verified.
How about using the two send without this if (sizeof(ds) == nSizeDS) ?
In this case without the if condition works, but I'm afraid this should be wrong.

Jochen Arndt 6-Apr-17 6:31am

Then it is not a DIB.
I will edit my answer and add a solution.

Member 12891988 6-Apr-17 6:49am

You think this should be correct?
I have substituted that condition with tihs if:
if(!nSizeDS){//failure}
else{//is a DIB}

here there the complete part of code:

ICONINFO oIconInfo;
if (::GetIconInfo(icon, &oIconInfo))
{
// Get bitmap info for colour mask
DIBSECTION ds;
int nSizeDS = ::GetObject(oIconInfo.hbmColor, sizeof(ds), &ds);
if(!nSizeDS){
cout <<"Failure!"<<endl;
}else{
// is a DIB
cout <<"Success!"<<endl;
// Send the DIBSECTION
send(newConnection, (CHAR*)&ds, sizeof(ds), NULL);
// Send raw bitmap
send(newConnection, (CHAR*)ds.dsBm.bmBits, ds.dsBmih.biSizeImage, NULL);
}
}

Jochen Arndt 6-Apr-17 7:06am

Yes, it is correct.
Passing a buffer large enough to hold a DIBSECTION and passing the appropriate size is a method to detect if a bitmap is a DIB or DDB. When it is a DDB, the buffer is filled with a BITMAP structure and the return value is sizeof(BITMAP).

Then a DIB has to be created because only with that the ds.dsBm.bmBits member pointing to the raw data is valid.

Member 12891988 6-Apr-17 11:38am

One last thing, side c#,
I receive data normally using this:
byte[] buffer = new byte[1500];
int iRx = sck.Receive(buffer);
char[] chars = new char[iRx];
System.Text.Decoder d = System.Text.Encoding.UTF8.GetDecoder();
int charLen = d.GetChars(buffer, 0, iRx, chars, 0);
System.String szData = new System.String(chars);

and then I print in listview like so:

listView1.Items.Add(szData)));

-----------------------------------------
But if I have to create the Icon, I have to use DIBSECTION ds to create the image/icon;

width = ds.dsBm.bmWidth;
height = ds.dsBm.bmHeight;
stride = ds.dsBm.bmWidthBytes;
ecc...
But how I can convert byte that I have received to DIBSECTION ds?
So if I convert byte array to ds I can use ds to create the Icon.

Jochen Arndt 6-Apr-17 11:59am

I'm not a C# expert (more C/C++).

One option is to create a C# structure for the DIBSECTION using [StructLayout(LayoutKind.Sequential, Pack=1)].

Then create a byte array with the size of the structure and receive into that buffer. Finally cast the array to the structure.

Member 12891988 6-Apr-17 8:07am

thank you