Add scratchpad

config.h

@@ -82,11 +82,14 @@ 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", normbgcolor, "-nf", normfgcolor, "-sb", selbgcolor, "-sf", selfgcolor, 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_p,      spawn,          {.v = dmenucmd } },
 	{ MODKEY|ShiftMask,             XK_Return, spawn,          {.v = termcmd } },
+	{ MODKEY,                       XK_s,      togglescratch,  {.v = scratchpadcmd } },
 	{ MODKEY,                       XK_b,      togglebar,      {0} },
 	{ MODKEY,                       XK_j,      focusstack,     {.i = +1 } },
 	{ MODKEY,                       XK_k,      focusstack,     {.i = -1 } },

dwm.c

@@ -252,6 +252,7 @@ static void tagmon(const Arg *arg);
 static void tile(Monitor *);
 static void togglebar(const Arg *arg);
 static void togglefloating(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);
@@ -339,6 +340,8 @@ static Colormap cmap;
 /* 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]; };
 
@@ -1266,6 +1269,14 @@ manage(Window w, XWindowAttributes *wa)
 		&& (c->x + (c->w / 2) < c->mon->wx + c->mon->ww)) ? bh : c->mon->my);
 	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);
@@ -1997,6 +2008,7 @@ spawn(const Arg *arg)
 {
 	if (arg->v == dmenucmd)
 		dmenumon[0] = '0' + selmon->num;
+	selmon->tagset[selmon->seltags] &= ~scratchtag;
 	if (fork() == 0) {
 		if (dpy)
 			close(ConnectionNumber(dpy));
@@ -2081,6 +2093,28 @@ togglefloating(const Arg *arg)
 	arrange(selmon);
 }
 
+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)
 {