Use HWND to toggle application fullscreen

Question

So I am trying to move another application to a second screen and then I want to set it full screen in C++.

I have the HWND handle from the application from a list of processes and then I can set the position from the window where I want with MoveWindow. This works perfectly.

Is there a similar way to set the application to full screen? I can only seem to find info about setting your own application to full screen. But in this case I want to be able to move any application I want and set it to full screen. (As far as this is possible, but for the purpose I need it it should be)

If I press Alt+Enter on the window after moving it, it does exactly what I want. So I hope I can do that from code?

EDIT: BTW I tried ShowWindow(windowToMove, SHOW_FULLSCREEN); But it seems to maximize it but it is not similar to ALT+ENTER.

Thanks for any help in advance!

You need to find an API exposed by the second app to trigger the full screen mode. Otherwise its internal state will get all messed up. — Raymond Chen, Apr 08 '16 at 16:16
Thanks I already had a feeling that would be the only option. But I wasn't sure. — Alexander S., Apr 12 '16 at 12:54

score 3 · Answer 1 · answered Jan 08 '17 at 18:49

BOOL IsWindowMode = TRUE;
WINDOWPLACEMENT wpc;
LONG HWNDStyle = 0;
LONG HWNDStyleEx = 0;

void FullScreenSwitch( )
{
    if ( IsWindowMode )
    {
        IsWindowMode = FALSE;
        GetWindowPlacement( HWNDWindow, &wpc );
        if ( HWNDStyle == 0 )
            HWNDStyle = GetWindowLong( HWNDWindow, GWL_STYLE );
        if ( HWNDStyleEx == 0 )
            HWNDStyleEx = GetWindowLong( HWNDWindow, GWL_EXSTYLE );

        LONG NewHWNDStyle = HWNDStyle;
        NewHWNDStyle &= ~WS_BORDER;
        NewHWNDStyle &= ~WS_DLGFRAME;
        NewHWNDStyle &= ~WS_THICKFRAME;

        LONG NewHWNDStyleEx =HWNDStyleEx;
        NewHWNDStyleEx &= ~WS_EX_WINDOWEDGE;

        SetWindowLong( HWNDWindow, GWL_STYLE, NewHWNDStyle | WS_POPUP );
        SetWindowLong( HWNDWindow, GWL_EXSTYLE, NewHWNDStyleEx | WS_EX_TOPMOST );
        ShowWindow( HWNDWindow, SW_SHOWMAXIMIZED );
    }
    else
    {
        IsWindowMode = TRUE;
        SetWindowLong( HWNDWindow, GWL_STYLE, HWNDStyle );
        SetWindowLong( HWNDWindow, GWL_EXSTYLE, HWNDStyleEx );
        ShowWindow( HWNDWindow, SW_SHOWNORMAL );
        SetWindowPlacement( HWNDWindow, &wpc );
    }
}

This code switch windowed window to fullscreen and back. (WINAPI, and need start target process in window mode)

Use HWND to toggle application fullscreen

1 Answers1