How to check if an other program is running in fullscreen mode, eg. a media player

Question

How can I check if an other app is running in full screen mode & topmost in c++ MFC? I just want to disable all of my auto dialogs (warnings) if media player or other players are running. (Like silent/gamer mode in Avast.) How could I do that?

Thank you.

Answer 1

using a combination of EnumWindows, GetWindowInfo and GetWindowRect does the trick.

bool IsTopMost( HWND hwnd )
{
  WINDOWINFO info;
  GetWindowInfo( hwnd, &info );
  return ( info.dwExStyle & WS_EX_TOPMOST ) ? true : false;
}

bool IsFullScreenSize( HWND hwnd, const int cx, const int cy )
{
  RECT r;
  ::GetWindowRect( hwnd, &r );
  return r.right - r.left == cx && r.bottom - r.top == cy;
}

bool IsFullscreenAndMaximized( HWND hwnd )
{
  if( IsTopMost( hwnd ) )
  {
    const int cx = GetSystemMetrics( SM_CXSCREEN );
    const int cy = GetSystemMetrics( SM_CYSCREEN );
    if( IsFullScreenSize( hwnd, cx, cy ) )
      return true;
  }
  return false;
}

BOOL CALLBACK CheckMaximized( HWND hwnd, LPARAM lParam )
{
  if( IsFullscreenAndMaximized( hwnd ) )
  {
    * (bool*) lParam = true;
    return FALSE; //there can be only one so quit here
  }
  return TRUE;
}

bool bThereIsAFullscreenWin = false;
EnumWindows( (WNDENUMPROC) CheckMaximized, (LPARAM) &bThereIsAFullscreenWin );

edit2: updated with tested code, which works fine here for MediaPlayer on Windows 7. I tried with GetForeGroundWindow instead of the EnumWindows, but then the IsFullScreenSize() check only works depending on which area of media player the mouse is in exactly.

Note that the problem with multimonitor setups mentioned in the comment below is still here.