CODEWITHSUNDEEP
c++winapi
lebron2323
lebron2323

Reputation: 1040

Detecting full screen mode in Windows

I need to detect if some application is currently running in full screen mode. If yes, then I must stop my application. So, how can I detect that? p.s. Win32 C++

Upvotes: 18

Views: 10725

Answers (5)

Andrei Moiseev
Andrei Moiseev

Reputation: 4074

All other answers are rather hackish.

Windows Vista, Windows 7 and up support SHQueryUserNotificationState():

QUERY_USER_NOTIFICATION_STATE pquns;
SHQueryUserNotificationState(&pquns);

From this "notification state" it is possible to infer the fullscreen state. Basically, when there is an an app running in fullscreen mode, Windows reports a "busy" notification state.

  • QUNS_NOT_PRESENT - not fullscreen (machine locked/screensaver/user switching)
  • QUNS_BUSY – fullscreen (the F11 fullscreen, also all video games I tried use this)
  • QUNS_RUNNING_D3D_FULL_SCREEN – fullscreen (Direct3D application is running in exclusive mode, i.e. fullscreen)
  • QUNS_PRESENTATION_MODE – fullscreen (a special mode for showing presentations, which are fullscreen)
  • QUNS_ACCEPTS_NOTIFICATIONS – not fullscreen
  • QUNS_QUIET_TIME – not fullscreen
  • QUNS_APP – probably fullscreen (not sure: "Introduced in Windows 8. A Windows Store app is running.")

Upvotes: 22

Hunaja
Hunaja

Reputation: 99

Hooch's and ens' answers actually don't work on a multiple monitor system. That's because

The rectangle of the desktop window returned by GetWindowRect or GetClientRect is always equal to the rectangle of the primary monitor, for compatibility with existing applications.

See https://learn.microsoft.com/en-us/windows/desktop/gdi/multiple-monitor-system-metrics for reference.

The above means that if the window is fullscreen on a monitor that's not the primary monitor of the system, the coordinates (which are relative to the virtual screen) are completely different from the coordinates of the desktop window.

I fixed this with the following function:

bool isFullscreen(HWND windowHandle)
{
    MONITORINFO monitorInfo = { 0 };
    monitorInfo.cbSize = sizeof(MONITORINFO);
    GetMonitorInfo(MonitorFromWindow(windowHandle, MONITOR_DEFAULTTOPRIMARY), &monitorInfo);

    RECT windowRect;
    GetWindowRect(windowHandle, &windowRect);

    return windowRect.left == monitorInfo.rcMonitor.left
        && windowRect.right == monitorInfo.rcMonitor.right
        && windowRect.top == monitorInfo.rcMonitor.top
        && windowRect.bottom == monitorInfo.rcMonitor.bottom;
}

Upvotes: 7

BullyWiiPlaza
BullyWiiPlaza

Reputation: 19185

Here's also a Java JNA implementation based on ens' answer:

public static boolean isFullScreen()
{
    WinDef.HWND foregroundWindow = GetForegroundWindow();
    WinDef.RECT foregroundRectangle = new WinDef.RECT();
    WinDef.RECT desktopWindowRectangle = new WinDef.RECT();
    User32.INSTANCE.GetWindowRect(foregroundWindow, foregroundRectangle);
    WinDef.HWND desktopWindow = User32.INSTANCE.GetDesktopWindow();
    User32.INSTANCE.GetWindowRect(desktopWindow, desktopWindowRectangle);
    return foregroundRectangle.toString().equals(desktopWindowRectangle.toString());
}

Note that the toString() comparison at the bottom is a small hack to avoid comparing 4 elements to each other.

Upvotes: 0

ens
ens

Reputation: 1098

A full implementation of Hooch's answer:

bool isFullscreen(HWND window)
{
    RECT a, b;
    GetWindowRect(window, &a);
    GetWindowRect(GetDesktopWindow(), &b);
    return (a.left   == b.left  &&
            a.top    == b.top   &&
            a.right  == b.right &&
            a.bottom == b.bottom);
}

Upvotes: 5

Hooch
Hooch

Reputation: 29673

hWnd = GetForegroundWindow();
RECT appBounds;
RECT rc;
GetWindowRect(GetDesktopWindow(), &rc);

Then check if that windows isn't desktop or shell. Simple if instruction.

if(hWnd =! GetDesktopWindow() && hWnd != GetShellWindow())
{
    GetWindowRect(hWnd, &appBounds);
    // Now you just have to compare rc to appBounds
}

This is written without testing.

Upvotes: 11

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