Added bottomstack layout

Many users new to dwm find themselves caught out by being kicked out to the login manager (dwm crashing) when they open 50+ clients for demonstration purposes. The number of clients reported varies depending on the resolution of the monitor.

The cause of this is due to how the default tile layout calculates the height of the next client based on the position of the previous client. Because clients have a minimum size the (ty) position can exceed that of the window height, resulting in (m->wh - ty) becoming negative. The negative height stored as an unsigned int results in a very large height ultimately resulting in dwm crashing.

This patch adds safeguards to prevent the ty and my positions from exceeding that of the window height.

config.def.h

@@ -41,6 +41,8 @@ static const Layout layouts[] = {
 	{ "[]=",      tile },    /* first entry is default */
 	{ "><>",      NULL },    /* no layout function means floating behavior */
 	{ "[M]",      monocle },
+	{ "TTT",      bstack },
+	{ "===",      bstackhoriz },
 };
 
 /* key definitions */
@@ -76,6 +78,8 @@ static Key keys[] = {
 	{ MODKEY,                       XK_t,      setlayout,      {.v = &layouts[0]} },
 	{ MODKEY,                       XK_f,      setlayout,      {.v = &layouts[1]} },
 	{ MODKEY,                       XK_m,      setlayout,      {.v = &layouts[2]} },
+	{ MODKEY,                       XK_u,      setlayout,      {.v = &layouts[3]} },
+	{ MODKEY,                       XK_o,      setlayout,      {.v = &layouts[4]} },
 	{ MODKEY,                       XK_space,  setlayout,      {0} },
 	{ MODKEY|ShiftMask,             XK_space,  togglefloating, {0} },
 	{ MODKEY,                       XK_0,      view,           {.ui = ~0 } },

config.mk

@@ -25,7 +25,7 @@ INCS = -I${X11INC} -I${FREETYPEINC}
 LIBS = -L${X11LIB} -lX11 ${XINERAMALIBS} ${FREETYPELIBS}
 
 # flags
-CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_C_SOURCE=2 -DVERSION=\"${VERSION}\" ${XINERAMAFLAGS}
+CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_POSIX_C_SOURCE=200809L -DVERSION=\"${VERSION}\" ${XINERAMAFLAGS}
 #CFLAGS   = -g -std=c99 -pedantic -Wall -O0 ${INCS} ${CPPFLAGS}
 CFLAGS   = -std=c99 -pedantic -Wall -Wno-deprecated-declarations -Os ${INCS} ${CPPFLAGS}
 LDFLAGS  = ${LIBS}

dwm.c

@@ -169,6 +169,7 @@ static void focus(Client *c);
 static void focusin(XEvent *e);
 static void focusmon(const Arg *arg);
 static void focusstack(const Arg *arg);
+static Atom getatomprop(Client *c, Atom prop);
 static int getrootptr(int *x, int *y);
 static long getstate(Window w);
 static int gettextprop(Window w, Atom atom, char *text, unsigned int size);
@@ -233,6 +234,8 @@ static int xerror(Display *dpy, XErrorEvent *ee);
 static int xerrordummy(Display *dpy, XErrorEvent *ee);
 static int xerrorstart(Display *dpy, XErrorEvent *ee);
 static void zoom(const Arg *arg);
+static void bstack(Monitor *m);
+static void bstackhoriz(Monitor *m);
 
 /* variables */
 static const char broken[] = "broken";
@@ -695,7 +698,7 @@ dirtomon(int dir)
 void
 drawbar(Monitor *m)
 {
-	int x, w, sw = 0;
+	int x, w, tw = 0;
 	int boxs = drw->fonts->h / 9;
 	int boxw = drw->fonts->h / 6 + 2;
 	unsigned int i, occ = 0, urg = 0;
@@ -704,8 +707,8 @@ drawbar(Monitor *m)
 	/* draw status first so it can be overdrawn by tags later */
 	if (m == selmon) { /* status is only drawn on selected monitor */
 		drw_setscheme(drw, scheme[SchemeNorm]);
-		sw = TEXTW(stext) - lrpad + 2; /* 2px right padding */
+		tw = TEXTW(stext) - lrpad + 2; /* 2px right padding */
-		drw_text(drw, m->ww - sw, 0, sw, bh, 0, stext, 0);
+		drw_text(drw, m->ww - tw, 0, tw, bh, 0, stext, 0);
 	}
 
 	for (c = m->clients; c; c = c->next) {
@@ -728,7 +731,7 @@ drawbar(Monitor *m)
 	drw_setscheme(drw, scheme[SchemeNorm]);
 	x = drw_text(drw, x, 0, w, bh, lrpad / 2, m->ltsymbol, 0);
 
-	if ((w = m->ww - sw - x) > bh) {
+	if ((w = m->ww - tw - x) > bh) {
 		if (m->sel) {
 			drw_setscheme(drw, scheme[m == selmon ? SchemeSel : SchemeNorm]);
 			drw_text(drw, x, 0, w, bh, lrpad / 2, m->sel->name, 0);
@@ -1520,7 +1523,7 @@ setmfact(const Arg *arg)
 	if (!arg || !selmon->lt[selmon->sellt]->arrange)
 		return;
 	f = arg->f < 1.0 ? arg->f + selmon->mfact : arg->f - 1.0;
-	if (f < 0.1 || f > 0.9)
+	if (f < 0.05 || f > 0.95)
 		return;
 	selmon->mfact = f;
 	arrange(selmon);
@@ -1688,10 +1691,12 @@ tile(Monitor *m)
 		if (i < m->nmaster) {
 			h = (m->wh - my) / (MIN(n, m->nmaster) - i);
 			resize(c, m->wx, m->wy + my, mw - (2*c->bw), h - (2*c->bw), 0);
+			if (my + HEIGHT(c) < m->wh)
 				my += HEIGHT(c);
 		} else {
 			h = (m->wh - ty) / (n - i);
 			resize(c, m->wx + mw, m->wy + ty, m->ww - mw - (2*c->bw), h - (2*c->bw), 0);
+			if (ty + HEIGHT(c) < m->wh)
 				ty += HEIGHT(c);
 		}
 }
@@ -2147,3 +2152,65 @@ main(int argc, char *argv[])
 	XCloseDisplay(dpy);
 	return EXIT_SUCCESS;
 }
+
+static void
+bstack(Monitor *m) {
+	int w, h, mh, mx, tx, ty, tw;
+	unsigned int i, n;
+	Client *c;
+
+	for (n = 0, c = nexttiled(m->clients); c; c = nexttiled(c->next), n++);
+	if (n == 0)
+		return;
+	if (n > m->nmaster) {
+		mh = m->nmaster ? m->mfact * m->wh : 0;
+		tw = m->ww / (n - m->nmaster);
+		ty = m->wy + mh;
+	} else {
+		mh = m->wh;
+		tw = m->ww;
+		ty = m->wy;
+	}
+	for (i = mx = 0, tx = m->wx, c = nexttiled(m->clients); c; c = nexttiled(c->next), i++) {
+		if (i < m->nmaster) {
+			w = (m->ww - mx) / (MIN(n, m->nmaster) - i);
+			resize(c, m->wx + mx, m->wy, w - (2 * c->bw), mh - (2 * c->bw), 0);
+			mx += WIDTH(c);
+		} else {
+			h = m->wh - mh;
+			resize(c, tx, ty, tw - (2 * c->bw), h - (2 * c->bw), 0);
+			if (tw != m->ww)
+				tx += WIDTH(c);
+		}
+	}
+}
+
+static void
+bstackhoriz(Monitor *m) {
+	int w, mh, mx, tx, ty, th;
+	unsigned int i, n;
+	Client *c;
+
+	for (n = 0, c = nexttiled(m->clients); c; c = nexttiled(c->next), n++);
+	if (n == 0)
+		return;
+	if (n > m->nmaster) {
+		mh = m->nmaster ? m->mfact * m->wh : 0;
+		th = (m->wh - mh) / (n - m->nmaster);
+		ty = m->wy + mh;
+	} else {
+		th = mh = m->wh;
+		ty = m->wy;
+	}
+	for (i = mx = 0, tx = m->wx, c = nexttiled(m->clients); c; c = nexttiled(c->next), i++) {
+		if (i < m->nmaster) {
+			w = (m->ww - mx) / (MIN(n, m->nmaster) - i);
+			resize(c, m->wx + mx, m->wy, w - (2 * c->bw), mh - (2 * c->bw), 0);
+			mx += WIDTH(c);
+		} else {
+			resize(c, tx, ty, m->ww - (2 * c->bw), th - (2 * c->bw), 0);
+			if (th != m->wh)
+				ty += HEIGHT(c);
+		}
+	}
+}