From f5fe34d1b382795ad47cd63cf43198c79c6845a5 Mon Sep 17 00:00:00 2001
From: bakkeby <bakkeby@gmail.com>
Date: Sat, 5 Sep 2020 14:32:26 +0200
Subject: [PATCH] Compilation of fullscreen patches for dwm.

This aims to provide a comprehensive fullscreen solution with the following features:
   - toggle fullscreen for any window using a single keybinding rather than having
     to rely on per-application keybindings
   - the ability to have windows go fullscreen within the size and position the
     window is currently in (fake fullscreen)
   - allow a fullscreen window to be moved to an adjacent monitor while remaining
     fullscreen
   - make fullscreen windows lose fullscreen if another (e.g. new) window on the
     same monitor receives focus, while still allowing dialog boxes to show while
     in fullscreen
   - allow seamless transition between the two fullscreen modes

The default keybindings are:
   - MOD+f to make a window fullscreen
   - MOD+Shift+f to make a window fake fullscreen

This incorporates, and expands on, the following patches:
   - fakefullscreenclient
   - togglefullscreen (a.k.a. actualfullscreen)
   - tagmonfixfs
   - losefullscreen
---
 config.def.h |   4 +-
 dwm.c        | 178 ++++++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 152 insertions(+), 30 deletions(-)

diff --git a/config.def.h b/config.def.h
index 1c0b587..5f28f2c 100644
--- a/config.def.h
+++ b/config.def.h
@@ -74,10 +74,12 @@ static Key keys[] = {
 	{ MODKEY,                       XK_Tab,    view,           {0} },
 	{ MODKEY|ShiftMask,             XK_c,      killclient,     {0} },
 	{ MODKEY,                       XK_t,      setlayout,      {.v = &layouts[0]} },
-	{ MODKEY,                       XK_f,      setlayout,      {.v = &layouts[1]} },
+	{ MODKEY,                       XK_e,      setlayout,      {.v = &layouts[1]} },
 	{ MODKEY,                       XK_m,      setlayout,      {.v = &layouts[2]} },
 	{ MODKEY,                       XK_space,  setlayout,      {0} },
 	{ MODKEY|ShiftMask,             XK_space,  togglefloating, {0} },
+	{ MODKEY,                       XK_f,      togglefullscreen, {0} },
+	{ MODKEY|ShiftMask,             XK_f,      togglefakefullscreen, {0} },
 	{ MODKEY,                       XK_0,      view,           {.ui = ~0 } },
 	{ MODKEY|ShiftMask,             XK_0,      tag,            {.ui = ~0 } },
 	{ MODKEY,                       XK_comma,  focusmon,       {.i = -1 } },
diff --git a/dwm.c b/dwm.c
index 4465af1..763c224 100644
--- a/dwm.c
+++ b/dwm.c
@@ -93,6 +93,7 @@ struct Client {
 	int bw, oldbw;
 	unsigned int tags;
 	int isfixed, isfloating, isurgent, neverfocus, oldstate, isfullscreen;
+	int fakefullscreen;
 	Client *next;
 	Client *snext;
 	Monitor *mon;
@@ -177,6 +178,7 @@ static void grabkeys(void);
 static void incnmaster(const Arg *arg);
 static void keypress(XEvent *e);
 static void killclient(const Arg *arg);
+static void losefullscreen(Client *next);
 static void manage(Window w, XWindowAttributes *wa);
 static void mappingnotify(XEvent *e);
 static void maprequest(XEvent *e);
@@ -210,7 +212,9 @@ static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
 static void tile(Monitor *);
 static void togglebar(const Arg *arg);
+static void togglefakefullscreen(const Arg *arg);
 static void togglefloating(const Arg *arg);
+static void togglefullscreen(const Arg *arg);
 static void toggletag(const Arg *arg);
 static void toggleview(const Arg *arg);
 static void unfocus(Client *c, int setfocus);
@@ -519,9 +523,12 @@ clientmessage(XEvent *e)
 		return;
 	if (cme->message_type == netatom[NetWMState]) {
 		if (cme->data.l[1] == netatom[NetWMFullscreen]
-		|| cme->data.l[2] == netatom[NetWMFullscreen])
+		|| cme->data.l[2] == netatom[NetWMFullscreen]) {
+			if (c->fakefullscreen == 2 && c->isfullscreen)
+				c->fakefullscreen = 3;
 			setfullscreen(c, (cme->data.l[0] == 1 /* _NET_WM_STATE_ADD    */
 				|| (cme->data.l[0] == 2 /* _NET_WM_STATE_TOGGLE */ && !c->isfullscreen)));
+		}
 	} else if (cme->message_type == netatom[NetActiveWindow]) {
 		if (c != selmon->sel && !c->isurgent)
 			seturgent(c, 1);
@@ -565,7 +572,7 @@ configurenotify(XEvent *e)
 			updatebars();
 			for (m = mons; m; m = m->next) {
 				for (c = m->clients; c; c = c->next)
-					if (c->isfullscreen)
+					if (c->isfullscreen && c->fakefullscreen != 1)
 						resizeclient(c, m->mx, m->my, m->mw, m->mh);
 				XMoveResizeWindow(dpy, m->barwin, m->wx, m->by, m->ww, bh);
 			}
@@ -785,8 +792,10 @@ focus(Client *c)
 {
 	if (!c || !ISVISIBLE(c))
 		for (c = selmon->stack; c && !ISVISIBLE(c); c = c->snext);
-	if (selmon->sel && selmon->sel != c)
+	if (selmon->sel && selmon->sel != c) {
+		losefullscreen(c);
 		unfocus(selmon->sel, 0);
+	}
 	if (c) {
 		if (c->mon != selmon)
 			selmon = c->mon;
@@ -834,6 +843,12 @@ focusstack(const Arg *arg)
 {
 	Client *c = NULL, *i;
 
+	/* Note that this patch is made for dwm 6.2. If applying this on top of the latest master
+	 * then the https://dwm.suckless.org/patches/alwaysfullscreen/ patch has been merged
+	 * upstream, which prevents focus to drift from windows that are in fake fullscreen.
+	 * To address this issue use this if statement instead:
+	 *   if (!selmon->sel || (selmon->sel->isfullscreen && selmon->sel->fakefullscreen != 1))
+	 */
 	if (!selmon->sel)
 		return;
 	if (arg->i > 0) {
@@ -1014,6 +1029,16 @@ killclient(const Arg *arg)
 	}
 }
 
+void
+losefullscreen(Client *next)
+{
+	Client *sel = selmon->sel;
+	if (!sel || !next)
+		return;
+	if (sel->isfullscreen && sel->fakefullscreen != 1 && ISVISIBLE(sel) && sel->mon == next->mon && !next->isfloating)
+		setfullscreen(sel, 0);
+}
+
 void
 manage(Window w, XWindowAttributes *wa)
 {
@@ -1068,8 +1093,10 @@ manage(Window w, XWindowAttributes *wa)
 		(unsigned char *) &(c->win), 1);
 	XMoveResizeWindow(dpy, c->win, c->x + 2 * sw, c->y, c->w, c->h); /* some windows require this */
 	setclientstate(c, NormalState);
-	if (c->mon == selmon)
+	if (c->mon == selmon) {
+		losefullscreen(c);
 		unfocus(selmon->sel, 0);
+	}
 	c->mon->sel = c;
 	arrange(c->mon);
 	XMapWindow(dpy, c->win);
@@ -1143,7 +1170,7 @@ movemouse(const Arg *arg)
 
 	if (!(c = selmon->sel))
 		return;
-	if (c->isfullscreen) /* no support moving fullscreen windows by mouse */
+	if (c->isfullscreen && c->fakefullscreen != 1) /* no support moving fullscreen windows by mouse */
 		return;
 	restack(selmon);
 	ocx = c->x;
@@ -1298,7 +1325,7 @@ resizemouse(const Arg *arg)
 
 	if (!(c = selmon->sel))
 		return;
-	if (c->isfullscreen) /* no support resizing fullscreen windows by mouse */
+	if (c->isfullscreen && c->fakefullscreen != 1) /* no support resizing fullscreen windows by mouse */
 		return;
 	restack(selmon);
 	ocx = c->x;
@@ -1472,29 +1499,79 @@ setfocus(Client *c)
 void
 setfullscreen(Client *c, int fullscreen)
 {
-	if (fullscreen && !c->isfullscreen) {
-		XChangeProperty(dpy, c->win, netatom[NetWMState], XA_ATOM, 32,
-			PropModeReplace, (unsigned char*)&netatom[NetWMFullscreen], 1);
+	XEvent ev;
+	int savestate = 0, restorestate = 0, restorefakefullscreen = 0;
+
+	if ((c->fakefullscreen == 0 && fullscreen && !c->isfullscreen) // normal fullscreen
+			|| (c->fakefullscreen == 2 && fullscreen)) // fake fullscreen --> actual fullscreen
+		savestate = 1; // go actual fullscreen
+	else if ((c->fakefullscreen == 0 && !fullscreen && c->isfullscreen) // normal fullscreen exit
+			|| (c->fakefullscreen >= 2 && !fullscreen)) // fullscreen exit --> fake fullscreen
+		restorestate = 1; // go back into tiled
+
+	/* If leaving fullscreen and the window was previously fake fullscreen (2), then restore
+	 * that while staying in fullscreen. The exception to this is if we are in said state, but
+	 * the client itself disables fullscreen (3) then we let the client go out of fullscreen
+	 * while keeping fake fullscreen enabled (as otherwise there will be a mismatch between the
+	 * client and the window manager's perception of the client's fullscreen state). */
+	if (c->fakefullscreen == 2 && !fullscreen && c->isfullscreen) {
+		restorefakefullscreen = 1;
 		c->isfullscreen = 1;
-		c->oldstate = c->isfloating;
+		fullscreen = 1;
+	}
+
+	if (fullscreen != c->isfullscreen) { // only send property change if necessary
+		if (fullscreen)
+			XChangeProperty(dpy, c->win, netatom[NetWMState], XA_ATOM, 32,
+				PropModeReplace, (unsigned char*)&netatom[NetWMFullscreen], 1);
+		else
+			XChangeProperty(dpy, c->win, netatom[NetWMState], XA_ATOM, 32,
+				PropModeReplace, (unsigned char*)0, 0);
+	}
+
+	c->isfullscreen = fullscreen;
+
+	/* Some clients, e.g. firefox, will send a client message informing the window manager
+	 * that it is going into fullscreen after receiving the above signal. This has the side
+	 * effect of this function (setfullscreen) sometimes being called twice when toggling
+	 * fullscreen on and off via the window manager as opposed to the application itself.
+	 * To protect against obscure issues where the client settings are stored or restored
+	 * when they are not supposed to we add an additional bit-lock on the old state so that
+	 * settings can only be stored and restored in that precise order. */
+	if (savestate && !(c->oldstate & (1 << 1))) {
 		c->oldbw = c->bw;
+		c->oldstate = c->isfloating | (1 << 1);
 		c->bw = 0;
 		c->isfloating = 1;
 		resizeclient(c, c->mon->mx, c->mon->my, c->mon->mw, c->mon->mh);
 		XRaiseWindow(dpy, c->win);
-	} else if (!fullscreen && c->isfullscreen){
-		XChangeProperty(dpy, c->win, netatom[NetWMState], XA_ATOM, 32,
-			PropModeReplace, (unsigned char*)0, 0);
-		c->isfullscreen = 0;
-		c->isfloating = c->oldstate;
+	} else if (restorestate && (c->oldstate & (1 << 1))) {
 		c->bw = c->oldbw;
-		c->x = c->oldx;
-		c->y = c->oldy;
-		c->w = c->oldw;
-		c->h = c->oldh;
+		c->isfloating = c->oldstate = c->oldstate & 1;
+		if (restorefakefullscreen || c->fakefullscreen == 3)
+			c->fakefullscreen = 1;
+		/* The client may have been moved to another monitor whilst in fullscreen which if tiled
+		 * we address by doing a full arrange of tiled clients. If the client is floating then the
+		 * height and width may be larger than the monitor's window area, so we cap that by
+		 * ensuring max / min values. */
+		if (c->isfloating) {
+			c->x = MAX(c->mon->wx, c->oldx);
+			c->y = MAX(c->mon->wy, c->oldy);
+			c->w = MIN(c->mon->ww - c->x - 2*c->bw, c->oldw);
+			c->h = MIN(c->mon->wh - c->y - 2*c->bw, c->oldh);
+			resizeclient(c, c->x, c->y, c->w, c->h);
+			restack(c->mon);
+		} else
+			arrange(c->mon);
+	} else
 		resizeclient(c, c->x, c->y, c->w, c->h);
-		arrange(c->mon);
-	}
+
+	/* Exception: if the client was in actual fullscreen and we exit out to fake fullscreen
+	 * mode, then the focus would sometimes drift to whichever window is under the mouse cursor
+	 * at the time. To avoid this we ask X for all EnterNotify events and just ignore them.
+	 */
+	if (!c->isfullscreen)
+		while (XCheckMaskEvent(dpy, EnterWindowMask, &ev));
 }
 
 void
@@ -1665,9 +1742,19 @@ tag(const Arg *arg)
 void
 tagmon(const Arg *arg)
 {
-	if (!selmon->sel || !mons->next)
+	Client *c = selmon->sel;
+	if (!c || !mons->next)
 		return;
-	sendmon(selmon->sel, dirtomon(arg->i));
+	if (c->isfullscreen) {
+		c->isfullscreen = 0;
+		sendmon(c, dirtomon(arg->i));
+		c->isfullscreen = 1;
+		if (c->fakefullscreen != 1) {
+			resizeclient(c, c->mon->mx, c->mon->my, c->mon->mw, c->mon->mh);
+			XRaiseWindow(dpy, c->win);
+		}
+	} else
+		sendmon(c, dirtomon(arg->i));
 }
 
 void
@@ -1705,18 +1792,51 @@ togglebar(const Arg *arg)
 	arrange(selmon);
 }
 
+void
+togglefakefullscreen(const Arg *arg)
+{
+	Client *c = selmon->sel;
+	if (!c)
+		return;
+
+	if (c->fakefullscreen != 1 && c->isfullscreen) { // exit fullscreen --> fake fullscreen
+		c->fakefullscreen = 2;
+		setfullscreen(c, 0);
+	} else if (c->fakefullscreen == 1) {
+		setfullscreen(c, 0);
+		c->fakefullscreen = 0;
+	} else {
+		c->fakefullscreen = 1;
+		setfullscreen(c, 1);
+	}
+}
+
 void
 togglefloating(const Arg *arg)
 {
-	if (!selmon->sel)
+	Client *c = selmon->sel;
+	if (!c)
 		return;
-	if (selmon->sel->isfullscreen) /* no support for fullscreen windows */
+	if (c->isfullscreen && c->fakefullscreen != 1) /* no support for fullscreen windows */
 		return;
-	selmon->sel->isfloating = !selmon->sel->isfloating || selmon->sel->isfixed;
+	c->isfloating = !c->isfloating || c->isfixed;
 	if (selmon->sel->isfloating)
-		resize(selmon->sel, selmon->sel->x, selmon->sel->y,
-			selmon->sel->w, selmon->sel->h, 0);
-	arrange(selmon);
+		resize(c, c->x, c->y, c->w, c->h, 0);
+	arrange(c->mon);
+}
+
+void
+togglefullscreen(const Arg *arg)
+{
+	Client *c = selmon->sel;
+	if (!c)
+		return;
+
+	if (c->fakefullscreen == 1) { // fake fullscreen --> fullscreen
+		c->fakefullscreen = 2;
+		setfullscreen(c, 1);
+	} else
+		setfullscreen(c, !c->isfullscreen);
 }
 
 void
-- 
2.19.1