C / C++ / MFC

//
//  Purpose:
//    Copies a bitmap transparently onto the destination DC.
//
//  Returns:
//    None
//
void FooButton::TransparentBlt
  (HDC      hdcDest,            // destination device context
   int      nXDest,             // x-coord of destination rectangle's upper-left corner
   int      nYDest,             // y-coord of destination rectangle's upper-left corner
   int      nWidth,             // width of destination rectangle
   int      nHeight,            // height of destination rectangle
   HBITMAP  hBitmap,            // source bitmap
   int      nXSrc,              // x-coord of source rectangle's upper-left corner
   int      nYSrc,              // y-coord of source rectangle's upper-left corner
   COLORREF colorTransparent,   // transparent color
   HPALETTE hPal)               // logical palette to be used with bitmap (may be NULL)
{
  CDC dc, memDC, maskDC, tempDC;
  dc.Attach( hdcDest );
  maskDC.CreateCompatibleDC(&dc);
  CBitmap maskBitmap;
 
  // These store return of SelectObject() calls
  CBitmap* pOldMemBmp = NULL;
  CBitmap* pOldMaskBmp = NULL;
  HBITMAP hOldTempBmp = NULL;
 
  memDC.CreateCompatibleDC (&dc);
  tempDC.CreateCompatibleDC (&dc);
  CBitmap bmpImage;
  bmpImage.CreateCompatibleBitmap (&dc, nWidth, nHeight);
  pOldMemBmp = memDC.SelectObject (&bmpImage);
 
  // Select and realize the palette
  if (dc.GetDeviceCaps (RASTERCAPS) & RC_PALETTE && hPal) {
     ::SelectPalette( dc, hPal, FALSE );
     dc.RealizePalette();
     ::SelectPalette( memDC, hPal, FALSE );
  }
 
  hOldTempBmp = (HBITMAP) ::SelectObject (tempDC.m_hDC, hBitmap);
  memDC.BitBlt (0, 0, nWidth, nHeight, &tempDC, nXSrc, nYSrc, SRCCOPY);
 
  // Create monochrome bitmap for the mask
  maskBitmap.CreateBitmap (nWidth, nHeight, 1, 1, NULL);
  pOldMaskBmp = maskDC.SelectObject (&maskBitmap);
  memDC.SetBkColor (colorTransparent);
 
  // Create the mask from the memory DC
  maskDC.BitBlt (0, 0, nWidth, nHeight, &memDC, 0, 0, SRCCOPY);
 
  // Set the background in memDC to black. Using SRCPAINT with black
  // and any other color results in the other color, thus making
  // black the transparent color
  memDC.SetBkColor (RGB (0,0,0));
  memDC.SetTextColor (RGB (255,255,255));
  memDC.BitBlt (0, 0, nWidth, nHeight, &maskDC, 0, 0, SRCAND);
 
  // Set the foreground to black. See comment above.
  dc.SetBkColor (RGB (255,255,255));
  dc.SetTextColor (RGB (0,0,0));
  dc.BitBlt (nXDest, nYDest, nWidth, nHeight, &maskDC, 0, 0, SRCAND);
 
  // Combine the foreground with the background
  dc.BitBlt (nXDest, nYDest, nWidth, nHeight, &memDC, 0, 0, SRCPAINT);
 
  if (hOldTempBmp)
     ::SelectObject (tempDC.m_hDC, hOldTempBmp);
  if (pOldMaskBmp)
     maskDC.SelectObject (pOldMaskBmp);
  if (pOldMemBmp)
     memDC.SelectObject (pOldMemBmp);
 
  dc.Detach();
}

// Win 3.x and above
// Note: This technique may not necessarily work on printer devices.

// Create temporary Bitmaps
CBitmap bmpMask;
if( !bmpMask.CreateBitmap(
    bmSrc.bmWidth, bmSrc.bmHeight, 1, 1, NULL) )
{
    return FALSE;
}

CBitmap bmpTemp;
if( !bmpTemp.CreateCompatibleBitmap(
    pdcDest, bmSrc.bmWidth, bmSrc.bmHeight) )
{
    return FALSE;
}

// Create temporary DCs and select bitmaps into them
CWorkDC dcTemp(pdcDest, &bmpTemp);
CWorkDC dcMask(pdcDest, &bmpMask);

// Use temporary DC to reduce flicker
if( dcTemp.BitBlt(0, 0, bmSrc.bmWidth, bmSrc.bmHeight,
    pdcDest, xDest, yDest, SRCCOPY) )
{
    // If we made it here there should be no more possible problems

    // Create mask using crTransparent
    dcSrc.SetBkColor(crTrans);
    dcMask.BitBlt(0, 0, bmSrc.bmWidth, bmSrc.bmHeight,
        &dcSrc, 0,0, SRCCOPY);

    // Draw bitmap using mask
    dcTemp.BitBlt(0, 0, bmSrc.bmWidth, bmSrc.bmHeight,
        &dcSrc, 0, 0, SRCINVERT);
    dcTemp.BitBlt(0, 0, bmSrc.bmWidth, bmSrc.bmHeight,
        &dcMask, 0, 0, SRCAND);
    dcTemp.BitBlt(0, 0, bmSrc.bmWidth, bmSrc.bmHeight,
        &dcSrc, 0, 0, SRCINVERT);

    // Copy Temporary DC to Destination DC
    pdcDest->BitBlt(xDest, yDest, nWidth, hHeight,
        &dcTemp, 0, 0, SRCCOPY);
}

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

DWORD dwDesiredAccess = READ_CONTROL;

    if( TRUE == m_bSACL ) { dwDesiredAccess |= ACCESS_SYSTEM_SECURITY; }

    if( TRUE == bDirectory ) {

        hFile = CreateFile( pszFileObject, dwDesiredAccess, 0,
                            NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL );
    } else {

        hFile = CreateFile( pszFileObject, dwDesiredAccess, 0,
                            NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL );
    }

    if( hFile == INVALID_HANDLE_VALUE ) {

        outfile.WriteString( (CString)pszFileObject + _T("\n") );

        switch( GetLastError() ) {

        case ERROR_FILE_NOT_FOUND: /* 2 */
            outfile.WriteString( _T("  ERROR: The system cannot find the file specified.\n") );
            break;

        case ERROR_ACCESS_DENIED: /* 5 */
            outfile.WriteString( _T("  ERROR: Access Denied.\n") );
            break;

        case ERROR_BAD_NETPATH: /* 53 */
            outfile.WriteString( _T("  ERROR: The network path was not found.\n") );
            break;

        case ERROR_SHARING_VIOLATION:
            outfile.WriteString( _T("  ERROR: The process cannot access the file because it is being used by another process.\n") );
            break;

        case ERROR_PRIVILEGE_NOT_HELD: /* 1314 */
            outfile.WriteString( _T("  ERROR:  A required privilege is not held by the client.\n") );
            break;

        default:

            szMessage.Format( _T("  ERROR: %d\n"), GetLastError() );
            outfile.WriteString( szMessage );
        }

        outfile.WriteString( _T("\n") );

        return;
    }

CDC* pDC = GetDC();

// in OnDraw()
if( bFlag )
    // draw line