Make wmaker XRandR aware

This patch makes wmaker automatically Restart() to take into account
resolution changes done by xrandr.

The motivation to write this patch is that when I start my laptop connected
to an external monitor (VGA1), the resolution in the monitor is initially
wrong (perhaps this is a bug in XOrg or OpenSuse, but anyway), so I always
do this after starting wmaker:

xrandr --output VGA1 --preferred

The resolution in the external monitor gets fixed, but wmaker does not
recognize the change automatically and I have to manually restart it.

So this patch avoids the last step by making wmaker be XRandR-aware.
Wmaker now restarts automatically when it receives a RRChangeScreenNotify
event and I don't have to do the last part of the silly procedure described
above.

I am not sure if restarting wmaker is the most elegant solution, but
it at least solves part of my issue with wmaker + xrandr.

configure.ac

@@ -480,6 +480,21 @@ if test "$shape" = yes; then
 		shape=no, $XLFLAGS $XLIBS)
 fi
 
+dnl XRandR support
+dnl =============
+xrandr=yes
+AC_ARG_ENABLE(XRandR,
+[  --disable-xrandr         disable XRandR window extension support],
+		xrandr=$enableval, xrandr=yes)
+
+added_xext=no
+
+if test "$xrandr" = yes; then
+	AC_CHECK_LIB(Xrandr, XRRQueryExtension, [XLIBS="-lXrandr $XLIBS"
+		added_xext=yes
+		AC_DEFINE(HAVE_XRANDR, 1, [define if you want support for XRandR (set by configure)])],
+		xrandr=no, $XLFLAGS $XLIBS)
+fi
 
 dnl
 dnl libWINGS uses math functions, check whether usage requires linking
@@ -1072,6 +1087,7 @@ echo "Use assembly routines for wrlib     : $asm_support"
 echo "Use inline MMX(tm) x86 assembly     : $mmx_support"
 echo "Antialiased text support in WINGs   : $xft"
 echo "Xinerama extension support          : $xinerama"
+echo "XRandR extension support            : $xrandr"
 echo "Translated message files to install : $mof"
 dnl echo "Supported languages beside English  : $languages"
 if test "x$MOFILES" != "x"; then

src/event.c

@@ -40,6 +40,10 @@
 #include "xdnd.h"
 #endif
 
+#ifdef HAVE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
+
 #ifdef KEEP_XKB_LOCK_STATUS
 #include <X11/XKBlib.h>
 #endif				/* KEEP_XKB_LOCK_STATUS */
@@ -96,6 +100,11 @@ extern int wShapeEventBase;
 extern int wXkbEventBase;
 #endif
 
+#ifdef HAVE_XRANDR
+extern Bool has_randr;
+extern int randr_event_base;
+#endif
+
 /* special flags */
 /*extern char WDelayedActionSet;*/
 
@@ -562,6 +571,10 @@ static void handleExtensions(XEvent * event)
 		handleXkbIndicatorStateNotify(event);
 	}
 #endif				/*KEEP_XKB_LOCK_STATUS */
+#ifdef HAVE_XRANDR
+	if (has_randr && event->type == (randr_event_base + RRScreenChangeNotify))
+		Restart(NULL,True);
+#endif
 }
 
 static void handleMapRequest(XEvent * ev)

src/main.c

@@ -143,6 +143,11 @@ Bool wXkbSupported;
 int wXkbEventBase;
 #endif
 
+#ifdef HAVE_XRANDR
+Bool has_randr;
+int randr_event_base;
+#endif
+
 /* special flags */
 char WProgramSigState = 0;
 char WProgramState = WSTATE_NORMAL;

src/screen.c

@@ -35,9 +35,11 @@
 #ifdef KEEP_XKB_LOCK_STATUS
 #include <X11/XKBlib.h>
 #endif				/* KEEP_XKB_LOCK_STATUS */
+#ifdef HAVE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
 
 #include <wraster.h>
-
 #include "WindowMaker.h"
 #include "def_pixmaps.h"
 #include "screen.h"
@@ -77,6 +79,9 @@ extern int wScreenCount;
 #ifdef KEEP_XKB_LOCK_STATUS
 extern int wXkbSupported;
 #endif
+#ifdef HAVE_XRANDR
+extern int has_randr;
+#endif
 
 extern WDDomain *WDWindowMaker;
 
@@ -598,6 +603,11 @@ WScreen *wScreenInit(int screen_number)
 	}
 #endif				/* KEEP_XKB_LOCK_STATUS */
 
+#ifdef HAVE_XRANDR
+	if (has_randr)
+		XRRSelectInput(dpy, scr->root_win, RRScreenChangeNotifyMask);
+#endif
+
 	XSync(dpy, False);
 	XSetErrorHandler(oldHandler);
 

src/startup.c

@@ -45,6 +45,9 @@
 #ifdef KEEP_XKB_LOCK_STATUS
 #include <X11/XKBlib.h>
 #endif
+#ifdef HAVE_XRANDR
+#include <X11/extensions/Xrandr.h>
+#endif
 
 #include "WindowMaker.h"
 #include "GNUstep.h"
@@ -97,6 +100,11 @@ extern Bool wXkbSupported;
 extern int wXkbEventBase;
 #endif
 
+#ifdef HAVE_XRANDR
+extern Bool has_randr;
+extern int randr_event_base;
+#endif
+
 /* contexts */
 extern XContext wWinContext;
 extern XContext wAppWinContext;
@@ -501,7 +509,7 @@ static char *atomNames[] = {
 void StartUp(Bool defaultScreenOnly)
 {
 	struct sigaction sig_action;
-	int j, max;
+	int j, max, dummy;
 	Atom atom[sizeof(atomNames) / sizeof(char *)];
 
 	/*
@@ -692,6 +700,12 @@ void StartUp(Bool defaultScreenOnly)
 	wShapeSupported = XShapeQueryExtension(dpy, &wShapeEventBase, &j);
 #endif
 
+#ifdef HAVE_XRANDR
+	has_randr = XRRQueryExtension(dpy, &randr_event_base, &dummy);
+#else
+	has_randr = false;
+#endif
+
 #ifdef KEEP_XKB_LOCK_STATUS
 	wXkbSupported = XkbQueryExtension(dpy, NULL, &wXkbEventBase, NULL, NULL, NULL);
 	if (wPreferences.modelock && !wXkbSupported) {