L_ShowMagGlass

static L_BOOL   bLeftButton = FALSE;  
static HCURSOR  hMagGlassCursor = NULL; 
 
#define IDC_MAGGLASS_CURSOR 1234 
 
 L_INT StartMagnifyingGlassExample(L_HWND          hWnd, 
                            pBITMAPHANDLE pBitmap, 
                            pBITMAPHANDLE pUpdateBitmap, 
                            RECT*         prcView, 
                            HINSTANCE     hInst) 
{ 
   L_INT             nRet; 
   L_TCHAR           szMsg[256]= TEXT(""); 
   MAGGLASSOPTIONS   MagGlassOpt; 
 
   // Starting the Magnifying Glass 
   memset(&MagGlassOpt, 0, sizeof(MAGGLASSOPTIONS)); 
   MagGlassOpt.uStructSize    = sizeof(MAGGLASSOPTIONS); 
   MagGlassOpt.nWidth         = 100; 
   MagGlassOpt.nHeight        = 100; 
   MagGlassOpt.nZoom          = 400; 
   MagGlassOpt.clrPen         = RGB(255,0,0); 
   MagGlassOpt.hMagCursor     = NULL; 
   MagGlassOpt.clrBack        = RGB(128,128,128); 
   MagGlassOpt.bEllipse       = FALSE; 
   MagGlassOpt.nBorderSize    = 1; 
   MagGlassOpt.b3D            = TRUE; 
   MagGlassOpt.uPaintFlags    = 0; 
   MagGlassOpt.pMask          = NULL; 
   MagGlassOpt.uMaskCount     = 0; 
   MagGlassOpt.nCrosshair     = CROSSHAIR_FINE; 
   MagGlassOpt.bIgnoreRgn     = TRUE; 
   MagGlassOpt.bCenter        = TRUE; 
   MagGlassOpt.uMagGlassFlags = MAGGLASS_MANUAL_UPDATE; 
 
   nRet = L_StartMagGlass (hWnd, pBitmap, prcView, &MagGlassOpt, NULL, NULL); 
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Starting the Magnifying Glass, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
      return nRet;  
   } 
 
   // Updating the Magnifying Glass bitmap with another bitmap that has the  
   // same width and height.  
   nRet = L_UpdateMagGlassBitmap(hWnd, pUpdateBitmap, TRUE);  
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Trying to update the Magnifying Glass bitmap, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
      return nRet;  
   } 
 
   L_UpdateMagGlassPaintFlags(hWnd, DISPLAYMODE_SCALETOGRAY); //enable ScaleToGray for MagGlass 
 
   hMagGlassCursor = LoadCursor(hInst, MAKEINTRESOURCE(IDC_MAGGLASS_CURSOR)); 
   return SUCCESS;  
} 
 
L_BOOL Child_OnSetCursor(L_HWND hWnd, L_HWND hWndCursor, L_UINT codeHitTest, L_UINT msg) 
{ 
   if (codeHitTest != HTCLIENT)  
      return (FORWARD_WM_SETCURSOR(hWnd, hWndCursor, codeHitTest, msg, DefMDIChildProc)); 
 
   if (L_WindowHasMagGlass(hWnd) && !bLeftButton) 
      SetCursor(hMagGlassCursor); 
 
   return TRUE;  
} 
 
L_VOID Child_OnLButtonDown(L_HWND     hWnd, 
                           L_BOOL   fDoubleClick, 
                           L_INT    x, 
                           L_INT    y, 
                           L_UINT   keyFlags) 
{ 
   UNREFERENCED_PARAMETER(fDoubleClick); 
   UNREFERENCED_PARAMETER(x); 
   UNREFERENCED_PARAMETER(y); 
   UNREFERENCED_PARAMETER(keyFlags); 
   L_INT    nRet;  
   L_TCHAR   szMsg[256]=TEXT("");  
 
   if (!L_WindowHasMagGlass(hWnd))  
      return;  
 
   SetCapture(hWnd);  
   ShowCursor(FALSE);  
 
   nRet = L_SetMagGlassPos (hWnd, x, y);  
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Displaying Magnifying Glass, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
      return;  
   } 
 
   nRet = L_ShowMagGlass(hWnd, TRUE);  
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Displaying Magnifying Glass, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
      return;  
   } 
 
   bLeftButton = TRUE;  
} 
 
L_VOID Child_OnMouseMove(L_HWND    hWnd, 
                         L_INT   x, 
                         L_INT   y, 
                         L_UINT keyFlags)  
{ 
   UNREFERENCED_PARAMETER(x); 
   UNREFERENCED_PARAMETER(y); 
   UNREFERENCED_PARAMETER(keyFlags); 
   L_INT    nRet;  
   L_TCHAR   szMsg[256]=TEXT("");  
 
   if (!L_WindowHasMagGlass(hWnd) || !bLeftButton)  
      return;  
 
   nRet = L_SetMagGlassPos (hWnd, x, y);  
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Moving Magnifying Glass, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
   } 
} 
 
L_VOID Child_OnLButtonUp(L_HWND    hWnd, 
                         L_INT   x, 
                         L_INT   y, 
                         L_UINT  keyFlags)  
{ 
   UNREFERENCED_PARAMETER(x); 
   UNREFERENCED_PARAMETER(y); 
   UNREFERENCED_PARAMETER(keyFlags); 
   L_INT    nRet;  
   L_TCHAR   szMsg[256]=TEXT("");  
 
   if (!L_WindowHasMagGlass(hWnd) || !bLeftButton)  
      return;  
 
   ReleaseCapture(); 
 
   nRet = L_ShowMagGlass(hWnd, FALSE);  
   if (nRet != SUCCESS)  
   { 
      wsprintf(szMsg, TEXT("Error Hiding Magnifying Glass, Error: %d"), nRet);  
      MessageBox(hWnd, szMsg, TEXT("Error"), MB_ICONEXCLAMATION | MB_OK);  
   } 
 
   ShowCursor(TRUE);  
 
   bLeftButton = FALSE;  
}