Maximize: add 'fullscreen' option

Not all EWMH-aware applications make it obvious that they can be
fullscreened.  Let FVWM put windows into this state by adding a
'fullscreen' option to the 'Maximize' command.

NEWS

@@ -22,6 +22,7 @@ Changes in stable release 2.6.8 (UNRELEASED)
 
   - fvwm-menu-desktop(1) now requires python3 as an explicit
     dependency.
+  - Add a 'fullscreen' option to the 'Maximize' command.
 
 -------------------------------------------------------------------
 Changes in stable release 2.6.7 (06-Mar-2016)

doc/commands/Maximize.xml

@@ -69,7 +69,9 @@ The optional
 <replaceable>flags</replaceable>
 argument is a space separated list containing the following
 key words:
-<emphasis remap='I'>ewmhiwa</emphasis>, <emphasis remap='I'>growonwindowlayer</emphasis>, <emphasis remap='I'>growonlayers</emphasis> and <emphasis remap='I'>screen</emphasis>.
+<emphasis remap='I'>fullscreen</emphasis>, <emphasis remap='I'>ewmhiwa</emphasis>, <emphasis remap='I'>growonwindowlayer</emphasis>, <emphasis remap='I'>growonlayers</emphasis> and <emphasis remap='I'>screen</emphasis>.
+<fvwmopt cmd="Maximize" opt="fullscreen"/>
+causes the window to become fullscreened if the appropriate EWMH hint is set.
 <fvwmopt cmd="Maximize" opt="ewmhiwa"/>
 causes fvwm to ignore the <acronym>EWMH</acronym> working area.
 <fvwmopt cmd="Maximize" opt="growonwindowlayer"/>

fvwm/move_resize.c

@@ -4725,6 +4725,7 @@ void CMD_Maximize(F_CMD_ARGS)
 	Bool do_forget = False;
 	Bool is_screen_given = False;
 	Bool ignore_working_area = False;
+	Bool do_fullscreen = False;
 	int layers[2] = { -1, -1 };
 	Bool global_flag_parsed = False;
 	int  scr_x, scr_y;
@@ -4784,22 +4785,46 @@ void CMD_Maximize(F_CMD_ARGS)
 					layers[1] = -1;
 				}
 			}
+			else if (StrEquals(token, "fullscreen"))
+			{
+				do_fullscreen = True;
+				action = taction;
+			}
 			else
 			{
 				global_flag_parsed = True;
 			}
 		}
 	}
 	toggle = ParseToggleArgument(action, &action, -1, 0);
-	if (toggle == 0 && !IS_MAXIMIZED(fw))
-	{
+	if (do_fullscreen) {
+		if (toggle == -1) {
+			/* Flip-flop between fullscreen or not, if no toggle
+			 * argument is given.
+			 */
+			toggle = (IS_EWMH_FULLSCREEN(fw) ? 0 : 1);
+		}
+		if (toggle == 1 && !IS_EWMH_FULLSCREEN(fw)) {
+			EWMH_fullscreen(fw);
+			return;
+		}
+
+		if (toggle == 0 && IS_EWMH_FULLSCREEN(fw)) {
+			unmaximize_fvwm_window(fw);
+			return;
+		}
 		return;
-	}
+	} else {
+		if (toggle == 0 && !IS_MAXIMIZED(fw))
+		{
+			return;
+		}
 
-	if (toggle == 1 && IS_MAXIMIZED(fw))
-	{
-		/* Fake that the window is not maximized. */
-		do_force_maximize = True;
+		if (toggle == 1 && IS_MAXIMIZED(fw))
+		{
+			/* Fake that the window is not maximized. */
+			do_force_maximize = True;
+		}
 	}
 
 	/* find the new page and geometry */