gvimfullscreen.c

/*
 cl /LD gvimfullscreen.c user32.lib
 ------------------------------
 :call libcallnr("gvimfullscreen.dll", "EnableFullScreen", 1)
*/
#include <windows.h>

int g_x, g_y, g_dx, g_dy;

BOOL CALLBACK EnumChildProc(HWND hwnd, LPARAM lParam);

BOOL CALLBACK FindWindowProc(HWND hwnd, LPARAM lParam)
{
  HWND* pphWnd = (HWND*)lParam;

  if (GetParent(hwnd))
  {
    *pphWnd = NULL;
    return TRUE;
  }
  *pphWnd = hwnd;
  return FALSE;
}

LONG _declspec(dllexport) ToggleFullScreen()
{
  HWND hTop = NULL;
  DWORD dwThreadID;

  dwThreadID = GetCurrentThreadId();
  EnumThreadWindows(dwThreadID, FindWindowProc, (LPARAM)&hTop);

  if (hTop)
  {
    /* Determine the current state of the window */

    if ( GetWindowLong(hTop, GWL_STYLE) & WS_CAPTION )
    {
      /* Has a caption, so isn't maximised */

      MONITORINFO mi;
      RECT rc;
      HMONITOR hMonitor;

      GetWindowRect(hTop, &rc);
      hMonitor = MonitorFromRect(&rc, MONITOR_DEFAULTTONEAREST);

      //
      // get the work area or entire monitor rect.
      //
      mi.cbSize = sizeof(mi);
      GetMonitorInfo(hMonitor, &mi);

      g_x = mi.rcMonitor.left;
      g_y = mi.rcMonitor.top;
      g_dx = mi.rcMonitor.right - g_x;
      g_dy = mi.rcMonitor.bottom - g_y;
      //cx = GetSystemMetrics(SM_CXSCREEN);
      //cy = GetSystemMetrics(SM_CYSCREEN);

      /* Remove border, caption, and edges */
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_EXSTYLE) & ~WS_BORDER);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) & ~WS_CAPTION);
      SetWindowLong(hTop, GWL_EXSTYLE, GetWindowLong(hTop, GWL_STYLE) & ~WS_EX_CLIENTEDGE);
      SetWindowLong(hTop, GWL_EXSTYLE, GetWindowLong(hTop, GWL_STYLE) & ~WS_EX_WINDOWEDGE);

      SetWindowPos(hTop, HWND_TOP, g_x, g_y, g_dx, g_dy, SWP_SHOWWINDOW);

      /* Now need to find the child text area window
       * and set it's size accordingly
       */
      EnumChildWindows(hTop, EnumChildProc, 0);
    }
    else
    {
      /* Already full screen, so restore all the previous styles */
      SetWindowLong(hTop, GWL_EXSTYLE, GetWindowLong(hTop, GWL_EXSTYLE) | WS_BORDER);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_CAPTION);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_SYSMENU);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_MINIMIZEBOX);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_MAXIMIZEBOX);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_SYSMENU);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_EX_CLIENTEDGE);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_EX_WINDOWEDGE);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_THICKFRAME);
      SetWindowLong(hTop, GWL_STYLE, GetWindowLong(hTop, GWL_STYLE) | WS_DLGFRAME);


      SendMessage(hTop, WM_SYSCOMMAND, SC_RESTORE, 0);
      SendMessage(hTop, WM_SYSCOMMAND, SC_MAXIMIZE, 0);
    }
  }
  return GetLastError();
}

BOOL CALLBACK EnumChildProc(HWND hwnd, LPARAM lParam)
{
  char lpszClassName[100];
  HBRUSH b;

  UNREFERENCED_PARAMETER(lParam);

  GetClassName(hwnd, lpszClassName, 100);
  if ( strcmp(lpszClassName, "VimTextArea") == 0 )
  {
    //int cx, cy;
    //cx = GetSystemMetrics(SM_CXSCREEN);
    //cy = GetSystemMetrics(SM_CYSCREEN);

    SetWindowLong(hwnd, GWL_EXSTYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_EX_CLIENTEDGE);
    SetWindowLong(hwnd, GWL_EXSTYLE, GetWindowLong(hwnd, GWL_STYLE) & ~WS_EX_WINDOWEDGE);
    SetWindowPos(hwnd, HWND_TOP, 0, 0, g_dx, g_dy, SWP_SHOWWINDOW);

    b = CreateSolidBrush(RGB(0,0,0));
    SetClassLongPtr (hwnd, GCLP_HBRBACKGROUND, (LONG_PTR) b);
  }
  return TRUE;
}