Fullscreen.cpp

Fullscreen.cpp

HWND m_hWnd = ...;
bool m_fullscreen = false;
bool m_maximized = false;
DWORD m_old_style;
DWORD m_old_exstyle;
RECT m_old_rect;

void SetFullscreen(bool fullscreen)
{
    if (m_fullscreen == fullscreen)
        return;

    if (fullscreen)
    {
        m_maximized = !!::IsZoomed(m_hWnd);
        if (m_maximized)
        {
            ::SendMessage(m_hWnd, WM_SYSCOMMAND, SC_RESTORE, 0);
        }

        m_old_style = GetWindowLong(m_hWnd, GWL_STYLE);
        m_old_exstyle = GetWindowLong(m_hWnd, GWL_EXSTYLE);
        GetWindowRect(m_hWnd, &m_old_rect);

        DWORD style = m_old_style & ~(WS_CAPTION | WS_THICKFRAME);
        DWORD exstyle = m_old_exstyle & ~(WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE |
                                          WS_EX_DLGMODALFRAME | WS_EX_STATICEDGE);
        SetWindowLong(m_hWnd, GWL_STYLE, style);
        SetWindowLong(m_hWnd, GWL_EXSTYLE, exstyle);

        HMONITOR hMonitor = ::MonitorFromWindow(m_hWnd, MONITOR_DEFAULTTONEAREST);

        MONITORINFO mi;
        mi.cbSize = sizeof(mi);
        ::GetMonitorInfo(hMonitor, &mi);

        RECT& rect = mi.rcMonitor;
        ::SetWindowPos(m_hWnd, NULL, rect.left, rect.top,
                       rect.right - rect.left, rect.bottom - rect.top,
                       SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED);
    }
    else
    {
        SetWindowLong(m_hWnd, GWL_STYLE, m_old_style);
        SetWindowLong(m_hWnd, GWL_EXSTYLE, m_old_exstyle);

        RECT& rect = m_old_rect;
        ::SetWindowPos(m_hWnd, NULL, rect.left, rect.top,
                       rect.right - rect.left, rect.bottom - rect.top,
                       SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED);

        if (m_maximized)
            ::SendMessage(m_hWnd, WM_SYSCOMMAND, SC_MAXIMIZE, 0);
    }

    m_fullscreen = fullscreen;
}