Add scratchpad for terminal

config.def.h

@@ -65,11 +65,14 @@ static const Layout layouts[] = {
 /* commands */
 static const char *dmenucmd[] = { "dmenu_run", "-fn", dmenufont, "-nb", col_gray1, "-nf", col_gray3, "-sb", col_cyan, "-sf", col_gray4, NULL };
 static const char *termcmd[]  = { "st", NULL };
+static const char scratchpadname[] = "scratchpad";
+static const char *scratchpadcmd[] = { "st", "-t", scratchpadname, "-g", "120x34", NULL };
 
 static const Key keys[] = {
 	/* modifier                     key        function        argument */
 	{ MODKEY,                       XK_p,      spawn,          {.v = dmenucmd } },
 	{ MODKEY|ShiftMask,             XK_Return, spawn,          {.v = termcmd } },
+	{ MODKEY,                       XK_grave,  togglescratch,  {.v = scratchpadcmd } },
 	{ MODKEY,                       XK_b,      togglebar,      {0} },
 	{ MODKEY,                       XK_j,      focusstack,     {.i = +1 } },
 	{ MODKEY,                       XK_k,      focusstack,     {.i = -1 } },

config.h

@@ -94,12 +94,15 @@ static const Layout layouts[] = {
 static char dmenumon[2] = "0"; /* component of dmenucmd, manipulated in spawn() */
 static const char *dmenucmd[] = { "dmenu_run", "-m", dmenumon, "-fn", dmenufont, "-nb", col_gray1, "-nf", col_gray5, "-sb", col_gray2, "-sf", col_gray4, NULL };
 static const char *termcmd[]  = { "st", NULL };
+static const char scratchpadname[] = "scratchpad";
+static const char *scratchpadcmd[] = { "st", "-t", scratchpadname, "-g", "120x34", NULL };
 
 static Key keys[] = {
 	/* modifier                     key        function        argument */
 	{ MODKEY,                       XK_d,      spawn,          {.v = dmenucmd } },
 	{ MODKEY,                       XK_b,      spawn,          SHCMD("bt-menu") },
 	{ MODKEY,                       XK_Return, spawn,          {.v = termcmd } },
+    { MODKEY,                       XK_grave,  togglescratch,  {.v = scratchpadcmd } },
 	{ MODKEY,                       XK_j,      focusstack,     {.i = +1 } },
 	{ MODKEY,                       XK_k,      focusstack,     {.i = -1 } },
 	{ MODKEY,                       XK_i,      incnmaster,     {.i = +1 } },

dwm.c

@@ -261,6 +261,7 @@ static void tile(Monitor *m);
 static void togglebar(const Arg *arg);
 static void togglefloating(const Arg *arg);
 static void togglefullscr(const Arg *arg);
+static void togglescratch(const Arg *arg);
 static void toggletag(const Arg *arg);
 static void toggleview(const Arg *arg);
 static void unfocus(Client *c, int setfocus);
@@ -330,6 +331,8 @@ static xcb_connection_t *xcon;
 /* configuration, allows nested code to access above variables */
 #include "config.h"
 
+static unsigned int scratchtag = 1 << LENGTH(tags);
+
 /* compile-time check if all tags fit into an unsigned int bit array. */
 struct NumTags { char limitexceeded[LENGTH(tags) > 31 ? -1 : 1]; };
 
@@ -1262,6 +1265,14 @@ manage(Window w, XWindowAttributes *wa)
 	c->y = MAX(c->y, c->mon->wy);
 	c->bw = borderpx;
 
+	selmon->tagset[selmon->seltags] &= ~scratchtag;
+	if (!strcmp(c->name, scratchpadname)) {
+		c->mon->tagset[c->mon->seltags] |= c->tags = scratchtag;
+		c->isfloating = True;
+		c->x = c->mon->wx + (c->mon->ww / 2 - WIDTH(c) / 2);
+		c->y = c->mon->wy + (c->mon->wh / 2 - HEIGHT(c) / 2);
+	}
+
 	wc.border_width = c->bw;
 	XConfigureWindow(dpy, w, CWBorderWidth, &wc);
 	XSetWindowBorder(dpy, w, scheme[SchemeNorm][ColBorder].pixel);
@@ -1974,7 +1985,8 @@ sigchld(int unused)
 void
 spawn(const Arg *arg)
 {
-	if (fork() == 0) {
+    selmon->tagset[selmon->seltags] &= ~scratchtag;
+    if (fork() == 0) {
 		if (dpy)
 			close(ConnectionNumber(dpy));
 		setsid();
@@ -2097,6 +2109,28 @@ togglefullscr(const Arg *arg)
     setfullscreen(selmon->sel, !selmon->sel->isfullscreen);
 }
 
+void
+togglescratch(const Arg *arg)
+{
+	Client *c;
+	unsigned int found = 0;
+
+	for (c = selmon->clients; c && !(found = c->tags & scratchtag); c = c->next);
+	if (found) {
+		unsigned int newtagset = selmon->tagset[selmon->seltags] ^ scratchtag;
+		if (newtagset) {
+			selmon->tagset[selmon->seltags] = newtagset;
+			focus(NULL);
+			arrange(selmon);
+		}
+		if (ISVISIBLE(c)) {
+			focus(c);
+			restack(selmon);
+		}
+	} else
+		spawn(arg);
+}
+
 void
 toggletag(const Arg *arg)
 {