HANDLE CScopeView::DDBToDIB(CBitmap &bitmap, DWORD dwCompression, CPalette *pPal)
{
/* -----------------------------------------------------------
   | Fuction:     HANDLE CScopeView::DDBToDIB(...)           |
   | Description: Convert Device-Dependent Bitmap (DDB) to   |
   |              Device-independent Bitmap (DIB).           |
   | Return:      Void.                                      |
   | Date:        16/02/2002                                 |
   | Verison:     1.3                                        |
   | By:          Colin K McCord                             |
   ----------------------------------------------------------- */
 
        // DDBToDIB            - Creates a DIB from a DDB
        // bitmap              - Device dependent bitmap
        // dwCompression- Type of compression - see BITMAPINFOHEADER
        // pPal                - Logical palette
 
 
        BITMAP                        bm;
        BITMAPINFOHEADER       bi;
        LPBITMAPINFOHEADER     lpbi;
        DWORD                         dwLen;
        HANDLE                        hDIB;
        HANDLE                        handle;
        HDC                           hDC;
        HPALETTE                      hPal;
 
 
        ASSERT( bitmap.GetSafeHandle() );
 
        // The function has no arg for bitfields
        if( dwCompression == BI_BITFIELDS )
               return NULL;
 
        // If a palette has not been supplied use defaul palette
        hPal = (HPALETTE) pPal->GetSafeHandle();
        if (hPal==NULL)
               hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);
 
        // Get bitmap information
        bitmap.GetObject(sizeof(bm),(LPSTR)&bm);
 
        // Initialize the bitmapinfoheader
        bi.biSize                     = sizeof(BITMAPINFOHEADER);
        bi.biWidth                    = bm.bmWidth;
        bi.biHeight            = bm.bmHeight;
        bi.biPlanes            = 1;
        bi.biBitCount          = bm.bmPlanes * bm.bmBitsPixel;
        bi.biCompression       = dwCompression;
        bi.biSizeImage         = 0;
        bi.biXPelsPerMeter     = 0;
        bi.biYPelsPerMeter     = 0;
        bi.biClrUsed           = 0;
        bi.biClrImportant      = 0;
 
        // Compute the size of the  infoheader and the color table
        int nColors = (1 << bi.biBitCount);
 
        dwLen  = bi.biSize + nColors * sizeof(RGBQUAD);
 
        // We need a device context to get the DIB from
        hDC = ::GetDC(NULL);
 
        hPal = SelectPalette(hDC,hPal,FALSE);
        RealizePalette(hDC);
 
        // Allocate enough memory to hold bitmapinfoheader and color table
        hDIB = GlobalAlloc(GMEM_FIXED,dwLen);
 
        if (!hDIB)
        {
               SelectPalette(hDC,hPal,FALSE);
               ::ReleaseDC(NULL,hDC);
               return NULL;
        }
 
        lpbi = (LPBITMAPINFOHEADER)hDIB;
 
        *lpbi = bi;
 
        // Call GetDIBits with a NULL lpBits param, so the device driver 
        // will calculate the biSizeImage field 
        GetDIBits(hDC, (HBITMAP)bitmap.GetSafeHandle(), 0L, (DWORD)bi.biHeight,
                       (LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS);
 
        bi = *lpbi;
 
        // If the driver did not fill in the biSizeImage field, then compute it
        // Each scan line of the image is aligned on a DWORD (32bit) boundary
        if (bi.biSizeImage == 0){
               bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8) 
                                             * bi.biHeight;
 
               // If a compression scheme is used the result may infact be larger
               // Increase the size to account for this.
               if (dwCompression != BI_RGB)
                       bi.biSizeImage = (bi.biSizeImage * 3) / 2;
        }
 
        // Realloc the buffer so that it can hold all the bits
        dwLen += bi.biSizeImage;
        if (handle = GlobalReAlloc(hDIB, dwLen, GMEM_MOVEABLE))
               hDIB = handle;
        else{
               GlobalFree(hDIB);
 
               // Reselect the original palette
               SelectPalette(hDC,hPal,FALSE);
                       ::ReleaseDC(NULL,hDC);
               return NULL;
        }
 
        // Get the bitmap bits
        lpbi = (LPBITMAPINFOHEADER)hDIB;
 
        // FINALLY get the DIB
        BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),
                              0L,                           // Start scan line
                              (DWORD)bi.biHeight,           // # of scan lines
                              (LPBYTE)lpbi                  // address for bitmap bits
                              + (bi.biSize + nColors * sizeof(RGBQUAD)),
                              (LPBITMAPINFO)lpbi,           // address of bitmapinfo
                              (DWORD)DIB_RGB_COLORS);       // Use RGB for colour table
 
        if( !bGotBits )
        {
               GlobalFree(hDIB);
               SelectPalette(hDC,hPal,FALSE);
               ::ReleaseDC(NULL,hDC);
               return NULL;
        }
 
        SelectPalette(hDC,hPal,FALSE);
        ::ReleaseDC(NULL,hDC);
        return hDIB;
}