Windows全屏代码--摘自Chrome

变量定义：

    typedef struct SCREEN_INFO
    {
        DWORD dwStyle;
        DWORD dwExStyle;
        CRect rect;
        bool bMaximized;
    }SreenInfo;

    SreenInfo m_screenInfo;
    bool m_bFullScreen = false;

实现代码：

    if (!m_bFullScreen)
    {
         // Save current window information.  We force the window into restored mode
         // before going fullscreen because Windows doesn't seem to hide the
         // taskbar if the window is in the maximized state.
         m_screenInfo.bMaximized = !!::IsZoomed(this->m_hWnd);
//          if (m_screenInfo.bMaximized)
//               ::SendMessage(this->m_hWnd, WM_SYSCOMMAND, SC_RESTORE, 0);
         m_screenInfo.dwStyle = GetWindowLongPtr(this->m_hWnd, GWL_STYLE);
         m_screenInfo.dwExStyle = GetWindowLongPtr(this->m_hWnd, GWL_EXSTYLE);
         GetWindowRect(m_screenInfo.rect);
    }

    m_bFullScreen = !m_bFullScreen;

    if (m_bFullScreen)
    {
      // Set new window style and size.
        SetWindowLongPtr(this->m_hWnd, GWL_STYLE,
          m_screenInfo.dwStyle & ~(WS_CAPTION | WS_THICKFRAME));
        SetWindowLongPtr(this->m_hWnd, GWL_EXSTYLE,
          m_screenInfo.dwExStyle & ~(WS_EX_DLGMODALFRAME |
                            WS_EX_WINDOWEDGE | WS_EX_CLIENTEDGE | WS_EX_STATICEDGE));
           // On expand, if we're given a window_rect, grow to it, otherwise do
           // not resize.
      bool for_metro = false;
      if (!for_metro)
      {
          MONITORINFO monitor_info;
          monitor_info.cbSize = sizeof(monitor_info);
          GetMonitorInfo(MonitorFromWindow(this->m_hWnd, MONITOR_DEFAULTTONEAREST), & monitor_info);
          CRect window_rect(monitor_info.rcMonitor);
          SetWindowPos(NULL, window_rect.left, window_rect.top,
                             window_rect.Width(), window_rect.Height(),
                             SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED);
      }
    }
    else
    {
         // Reset original window style and size.  The multiple window size/moves
         // here are ugly, but if SetWindowPos() doesn't redraw, the taskbar won't be
         // repainted.  Better-looking methods welcome.
         SetWindowLongPtr(this->m_hWnd, GWL_STYLE, m_screenInfo.dwStyle);
         SetWindowLongPtr(this->m_hWnd, GWL_EXSTYLE, m_screenInfo.dwExStyle);

         // On restore, resize to the previous saved rect size.
         CRect new_rect(m_screenInfo.rect);
         SetWindowPos(NULL, new_rect.left, new_rect.top,
                      new_rect.Width(), new_rect.Height(),
                      SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED);
    }

参考：

1. https://stackoverflow.com/questions/2382464/win32-full-screen-and-hiding-taskbar，第一个高赞回答。

2.https://github.com/chromium/chromium/blob/master/ui/views/win/fullscreen_handler.cc, chromium 浏览器源代码。