Re: [GnomeMeeting-devel-list] Win32 fullscreen

[Michael Rickmann <mrickma gwdg de>]

Hello everybody,
I found out why returning from fullscreen in win32-Ekiga is/was still a 
hazard: A Windows window is not only owned by the process but also by the 
thread which has created it. A different thread can change the Show 
properties of that window but cannot destroy it.
gm_main_window_update_video in src/gui/main.cpp is used by two threads, at a 
different frequency though. When SDL_Init+SDL_SetVideoMode is executed by one 
thread and SDL_Quit by the other, SDL shuts down, but Windows forbids to 
destroy the SDL_app window. Why can I reliably remove that window by 
disconnecting ? I have not found the reason yet in the code. I suspect that 
both threads terminate and Windows in due corse destroys the window owned by 
one them.
I have attached two patches which try to circumvent this circumstance without 
changing the code too much. The first one is minimal, the second does the 
same but uses the WinMain function in SDLmain.a. For me they fix the hung 
SDL_app Window. But they do not address the problem which arises from the 
SDL_app Window being destroyed at presumed thread termination. If the calling 
state changes to stanby during fullscreen the window is destroyed, SDL_Quit 
is called but during the following calls SDL cannot open the fullscreen 
window again.
From a user's point of view this behaviour is tolerable, I think. When 
programming, however, I still try to find sort of a housekeeping thread in 
Ekiga which could do the SDL_Inits+SDL_SetVideoMode and SDL_Quits and let the 
others do the drawing. I have not been long enough with Ekiga to be really 
aquainted with its design. Any hints are welcome.
Regards
Michael Rickmann

diff -ur ekiga.orig/src/gui/main.cpp ekiga/src/gui/main.cpp
--- ekiga.orig/src/gui/main.cpp	2006-03-19 16:03:48.000000000 +0100
+++ ekiga/src/gui/main.cpp	2006-03-22 14:57:43.000000000 +0100
@@ -143,6 +143,9 @@
 
 #ifdef HAS_SDL
   SDL_Surface *screen;
+ #ifdef WIN32
+  DWORD sdls_threadid;
+ #endif
 #endif
 };
 
@@ -1634,7 +1637,11 @@
     mw->screen = SDL_SetVideoMode (gdk_screen_get_width (defaultscreen), gdk_screen_get_height (defaultscreen), 0, 
 				   SDL_SWSURFACE | SDL_HWSURFACE | 
 				   SDL_ANYFORMAT);
+#ifndef WIN32
     SDL_WM_ToggleFullScreen (mw->screen);
+#else
+  mw->sdls_threadid = GetCurrentThreadId();
+#endif
     SDL_ShowCursor (SDL_DISABLE);
   }
 }
@@ -1684,7 +1691,14 @@
 
   g_return_if_fail (mw != NULL);
 
+#ifndef WIN32
   SDL_Quit ();
+#else
+  if (mw->sdls_threadid == GetCurrentThreadId()) {
+    SDL_Quit ();
+    mw->sdls_threadid = 0;
+  }
+#endif
   mw->screen = NULL;
   
 }
Nur in ekiga/src/gui: main.cpp~.

diff -ur ekiga.orig/src/gui/main.cpp ekiga/src/gui/main.cpp
--- ekiga.orig/src/gui/main.cpp	2006-03-19 16:03:48.000000000 +0100
+++ ekiga/src/gui/main.cpp	2006-03-23 09:35:06.000000000 +0100
@@ -143,6 +143,9 @@
 
 #ifdef HAS_SDL
   SDL_Surface *screen;
+ #ifdef WIN32
+  DWORD sdls_threadid;
+ #endif
 #endif
 };
 
@@ -1630,11 +1633,21 @@
 
     defaultscreen = gdk_screen_get_default ();
 
+#ifndef WIN32
     SDL_Init (SDL_INIT_VIDEO);
+#else
+    SDL_InitSubSystem (SDL_INIT_VIDEO);
+    mw->sdls_threadid = GetCurrentThreadId();
+#endif
     mw->screen = SDL_SetVideoMode (gdk_screen_get_width (defaultscreen), gdk_screen_get_height (defaultscreen), 0, 
 				   SDL_SWSURFACE | SDL_HWSURFACE | 
+#if 0 // change to #ifdef WIN32
+				   SDL_FULLSCREEN |
+#endif
 				   SDL_ANYFORMAT);
+#ifndef WIN32
     SDL_WM_ToggleFullScreen (mw->screen);
+#endif
     SDL_ShowCursor (SDL_DISABLE);
   }
 }
@@ -1684,7 +1697,14 @@
 
   g_return_if_fail (mw != NULL);
 
-  SDL_Quit ();
+#ifndef WIN32
+  SDL_Quit();
+#else
+  if (mw->sdls_threadid == GetCurrentThreadId()) {
+    SDL_QuitSubSystem (SDL_INIT_VIDEO);
+    mw->sdls_threadid = 0;
+  }
+#endif
   mw->screen = NULL;
   
 }
@@ -4397,13 +4417,19 @@
 
 /* The main () */
 int 
-main (int argc, 
-      char ** argv, 
-      char ** envp)
+#if defined(WIN32) && defined(HAS_SDL)
+main (int argc, char ** argv)
+#else
+main (int argc, char ** argv, char ** envp)
+#endif
 {
   GMManager *endpoint = NULL;
 
+#if defined(WIN32) && defined(HAS_SDL)
+  PProcess::PreInitialise (argc, argv, NULL);
+#else
   PProcess::PreInitialise (argc, argv, envp);
+#endif
 
   GtkWidget *main_window = NULL;
   GtkWidget *druid_window = NULL;
@@ -4591,7 +4617,7 @@
 }
 
 
-#ifdef WIN32
+#if defined(WIN32) && !defined(HAS_SDL)
 int 
 APIENTRY WinMain (HINSTANCE hInstance,
 		  HINSTANCE hPrevInstance,