New option, set-titles-string, to allow the window title to be specified (as

for status-left/right) if set-titles is on. Also only update the title when the
status line is being redrawn.

cmd-set-option.c

@@ -69,6 +69,7 @@ const struct set_option_entry set_option_table[] = {
 	{ "repeat-time", SET_OPTION_NUMBER, 0, SHRT_MAX, NULL },
 	{ "set-remain-on-exit", SET_OPTION_FLAG, 0, 0, NULL },
 	{ "set-titles", SET_OPTION_FLAG, 0, 0, NULL },
+	{ "set-titles-string", SET_OPTION_STRING, 0, 0, NULL },
 	{ "status", SET_OPTION_FLAG, 0, 0, NULL },
 	{ "status-attr", SET_OPTION_ATTRIBUTES, 0, 0, NULL },
 	{ "status-bg", SET_OPTION_COLOUR, 0, 0, NULL },

server.c

@@ -66,6 +66,7 @@ void		 server_clean_dead(void);
 void		 server_lost_client(struct client *);
 void	 	 server_check_window(struct window *);
 void		 server_check_redraw(struct client *);
+void		 server_set_title(struct client *);
 void		 server_redraw_locked(struct client *);
 void		 server_check_timers(struct client *);
 void		 server_second_timers(void);
@@ -516,7 +517,6 @@ server_check_redraw(struct client *c)
 {
 	struct session		*s;
 	struct window_pane	*wp;
-	char		 	 title[512];
 	int		 	 flags, redraw;
 
 	if (c == NULL || c->session == NULL)
@@ -526,19 +526,10 @@ server_check_redraw(struct client *c)
 	flags = c->tty.flags & TTY_FREEZE;
 	c->tty.flags &= ~TTY_FREEZE;
 
-	if (options_get_number(&s->options, "set-titles")) {
-		xsnprintf(title, sizeof title, "%s:%u:%s - \"%s\"",
-		    s->name, s->curw->idx, s->curw->window->name,
-		    s->curw->window->active->screen->title);
-		if (c->title == NULL || strcmp(title, c->title) != 0) {
-			if (c->title != NULL)
-				xfree(c->title);
-			c->title = xstrdup(title);
-			tty_set_title(&c->tty, c->title);
-		}
-	}
-
 	if (c->flags & (CLIENT_REDRAW|CLIENT_STATUS)) {
+		if (options_get_number(&s->options, "set-titles"))
+			server_set_title(c);
+	
 		if (c->message_string != NULL)
 			redraw = status_message_redraw(c);
 		else if (c->prompt_string != NULL)
@@ -570,6 +561,26 @@ server_check_redraw(struct client *c)
 	c->flags &= ~(CLIENT_REDRAW|CLIENT_STATUS);
 }
 
+/* Set client title. */
+void
+server_set_title(struct client *c)
+{
+	struct session	*s = c->session;
+	const char	*template;
+	char		*title;
+
+	template = options_get_string(&s->options, "set-titles-string");
+	
+	title = status_replace(c->session, template, time(NULL));
+	if (c->title == NULL || strcmp(title, c->title) != 0) {
+		if (c->title != NULL)
+			xfree(c->title);
+		c->title = xstrdup(title);
+		tty_set_title(&c->tty, c->title);
+	}
+	xfree(title);
+}
+
 /* Redraw client when locked. */
 void
 server_redraw_locked(struct client *c)

tmux.1

@@ -1287,6 +1287,13 @@ This option is off by default.
 Note that elinks
 will only attempt to set the window title if the STY environment
 variable is set.
+.It Ic set-titles-string Ar string
+String used to set the window title if
+.Ic set-titles
+is on.
+Character sequences are replaced as for the
+.Ic status-left
+option.
 .It Xo Ic status
 .Op Ic on | off
 .Xc

tmux.c

@@ -413,6 +413,7 @@ main(int argc, char **argv)
 	options_set_number(so, "repeat-time", 500);
 	options_set_number(so, "set-remain-on-exit", 0);
 	options_set_number(so, "set-titles", 0);
+	options_set_string(so, "set-titles-string", "#S:#I:#W - \"#T\"");
 	options_set_number(so, "status", 1);
 	options_set_number(so, "status-attr", 0);
 	options_set_number(so, "status-bg", 2);