// Set window source to capture entire the desktop
	if (!MagSetWindowSource(hwndMag, sourceRect))
	{
		return;
	}
	// At this point, the callback function is called,
	// so we wait until the callback function is completely finished
	while (1)
	{
		if (bCallbacked)
		{
			break;
		}
	}
 
	// Get the file path to save
	LPCTSTR  szFilter;
	szFilter = _T("Windows Bitmap (*.BMP)|*.BMP||");
	CFileDialog fileDlg(FALSE, szFilter,
		_T("Untitled.bmp"), OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,
		szFilter, NULL, 0);
	if(fileDlg.DoModal() == IDOK)
	{
		//Save bmp to file
		CString pathName = fileDlg.GetPathName();
		SaveBmpToFile(bmif, pData, pathName);
	}
}

 BOOL WINAPI MagSetWindowSource(HWND hwnd, RECT rect);