workarround with CreateDIBSection

Hi all,

i would like to scan a certain range of my desktop for a certain pixel colour
in always recurring distances. The whole should run in the background (i use WinXP
Prof) and as fast as possible. First i tried it with "GetPixel" (see the code with
GetPixel) and i could do it successfully. But the handicap is that with bigger
ranges "GetPixel" is simply to slow!

In the meantime i have read that there is a quicker possibility with "CreateDIBSection"
Now i tried to do the same work with "CreateDIBSectio" but i couldnt resovlve that
problem. Can anybody help me and give me a codesnippet that do the same work as the
GetPixel-code-example? It would be very very nice :-)


regards, rommi (C++ Beginner)


****** code with GetPixel ************

Code:

---

int x, y;
HDC dc = GetDC(0);
int seekpix = 16777215;

while(true)
{
  for(x=100; x < 500; x++)
  {               
        for(y=200; y < 800; y++)
        {
          //=========== Desktop-Pixelfarbe ermitteln
          COLORREF deskpix = GetPixel(dc, y, x);

          //=========== Desktop-Pixelfarbe mit Suchpixel vergleich
          if(deskpix == seekpix)
          {
                    //execute further code
          }
        }
  }
}

---

****** my try with CreateDIBSection *****

Code:

---

        // Deklaration
        HDC hdc_screen;
        BITMAPINFO    bmi;
        LPBYTE      pBits;
        int x=500;
        int y=800;

        // window-id
        HWND desktopHandle = GetDesktopWindow();

        // device-context
        hdc_screen = GetDC(desktopHandle);

        // clean
        ZeroMemory(&bmi, sizeof(bmi));

        // Parameter DIBSection
        bmi.bmiHeader.biSize        = sizeof(BITMAPINFOHEADER);
        bmi.bmiHeader.biWidth        = x;
        bmi.bmiHeader.biHeight        = y;
        bmi.bmiHeader.biPlanes        = 1;
        bmi.bmiHeader.biBitCount    = 24;
        bmi.bmiHeader.biCompression = BI_RGB;

        // Create DibSection       
        HBITMAP hdcBmp = CreateDIBSection(hdc_screen, &bmi, DIB_RGB_COLORS, (void **)&pBits, NULL, 0);

        // ??????
        // ??????

---