Add resize-pane -Z to temporary zoom the active pane to occupy the full window

or unzoom (restored to the normal layout) if it already zoomed, bound to C-b z
by default. The pane is unzoomed on pretty much any excuse whatsoever.

We considered making this a new layout but the requirements are quite different
from layouts so decided it is better as a special case. Each current layout
cell is saved, a temporary one-cell layout generated and all except the active
pane set to NULL.

Prompted by suggestions and scripts from several. Thanks to Aaron Jensen and
Thiago Padilha for testing an earlier version.

cmd-break-pane.c

@@ -63,6 +63,8 @@ cmd_break_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	}
 
 	w = wl->window;
+	server_unzoom_window(w);
+
 	TAILQ_REMOVE(&w->panes, wp, entry);
 	if (wp == w->active) {
 		w->active = w->last;
@@ -82,7 +84,7 @@ cmd_break_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	name = default_window_name(w);
 	window_set_name(w, name);
 	free(name);
-	layout_init(w);
+	layout_init(w, wp);
 
 	base_idx = options_get_number(&s->options, "base-index");
 	wl = session_attach(s, w, -1 - base_idx, &cause); /* can't fail */

cmd-join-pane.c

@@ -91,11 +91,13 @@ join_pane(struct cmd *self, struct cmd_q *cmdq, int not_same_window)
 		return (CMD_RETURN_ERROR);
 	dst_w = dst_wl->window;
 	dst_idx = dst_wl->idx;
+	server_unzoom_window(dst_w);
 
 	src_wl = cmd_find_pane(cmdq, args_get(args, 's'), NULL, &src_wp);
 	if (src_wl == NULL)
 		return (CMD_RETURN_ERROR);
 	src_w = src_wl->window;
+	server_unzoom_window(src_w);
 
 	if (not_same_window && src_w == dst_w) {
 		cmdq_error(cmdq, "can't join a pane to its own window");

cmd-kill-pane.c

@@ -47,6 +47,7 @@ cmd_kill_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	if ((wl = cmd_find_pane(cmdq, args_get(args, 't'), NULL, &wp)) == NULL)
 		return (CMD_RETURN_ERROR);
+	server_unzoom_window(wl->window);
 
 	if (window_count_panes(wl->window) == 1) {
 		/* Only one pane, kill the window. */

cmd-resize-pane.c

@@ -31,8 +31,8 @@ enum cmd_retval	 cmd_resize_pane_exec(struct cmd *, struct cmd_q *);
 
 const struct cmd_entry cmd_resize_pane_entry = {
 	"resize-pane", "resizep",
-	"DLRt:Ux:y:", 0, 1,
-	"[-DLRU] [-x width] [-y height] " CMD_TARGET_PANE_USAGE " [adjustment]",
+	"DLRt:Ux:y:Z", 0, 1,
+	"[-DLRUZ] [-x width] [-y height] " CMD_TARGET_PANE_USAGE " [adjustment]",
 	0,
 	cmd_resize_pane_key_binding,
 	NULL,
@@ -75,6 +75,10 @@ cmd_resize_pane_key_binding(struct cmd *self, int key)
 		self->args = args_create(1, "5");
 		args_set(self->args, 'R', NULL);
 		break;
+	case 'z':
+		self->args = args_create(0);
+		args_set(self->args, 'Z', NULL);
+		break;
 	default:
 		self->args = args_create(0);
 		break;
@@ -86,6 +90,7 @@ cmd_resize_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 {
 	struct args		*args = self->args;
 	struct winlink		*wl;
+	struct window		*w;
 	const char	       	*errstr;
 	char			*cause;
 	struct window_pane	*wp;
@@ -94,6 +99,18 @@ cmd_resize_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	if ((wl = cmd_find_pane(cmdq, args_get(args, 't'), NULL, &wp)) == NULL)
 		return (CMD_RETURN_ERROR);
+	w = wl->window;
+
+	if (args_has(args, 'Z')) {
+		if (w->flags & WINDOW_ZOOMED)
+			window_unzoom(w);
+		else
+			window_zoom(wp);
+		server_redraw_window(w);
+		server_status_window(w);
+		return (CMD_RETURN_NORMAL);
+	}
+	server_unzoom_window(w);
 
 	if (args->argc == 0)
 		adjust = 1;

cmd-respawn-window.c

@@ -87,7 +87,7 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_q *cmdq)
 		server_destroy_pane(wp);
 		return (CMD_RETURN_ERROR);
 	}
-	layout_init(w);
+	layout_init(w, wp);
 	window_pane_reset_mode(wp);
 	screen_reinit(&wp->base);
 	input_init(wp);

cmd-select-layout.c

@@ -92,6 +92,7 @@ cmd_select_layout_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	if ((wl = cmd_find_window(cmdq, args_get(args, 't'), NULL)) == NULL)
 		return (CMD_RETURN_ERROR);
+	server_unzoom_window(wl->window);
 
 	next = self->entry == &cmd_next_layout_entry;
 	if (args_has(self->args, 'n'))

cmd-select-pane.c

@@ -90,6 +90,7 @@ cmd_select_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	if ((wl = cmd_find_pane(cmdq, args_get(args, 't'), NULL, &wp)) == NULL)
 		return (CMD_RETURN_ERROR);
 
+	server_unzoom_window(wp->window);
 	if (!window_pane_visible(wp)) {
 		cmdq_error(cmdq, "pane not visible");
 		return (CMD_RETURN_ERROR);

cmd-split-window.c

@@ -72,6 +72,7 @@ cmd_split_window_exec(struct cmd *self, struct cmd_q *cmdq)
 	if ((wl = cmd_find_pane(cmdq, args_get(args, 't'), &s, &wp)) == NULL)
 		return (CMD_RETURN_ERROR);
 	w = wl->window;
+	server_unzoom_window(w);
 
 	environ_init(&env);
 	environ_copy(&global_environ, &env);

cmd-swap-pane.c

@@ -63,6 +63,7 @@ cmd_swap_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 	if (dst_wl == NULL)
 		return (CMD_RETURN_ERROR);
 	dst_w = dst_wl->window;
+	server_unzoom_window(dst_w);
 
 	if (!args_has(args, 's')) {
 		src_w = dst_w;
@@ -82,6 +83,7 @@ cmd_swap_pane_exec(struct cmd *self, struct cmd_q *cmdq)
 			return (CMD_RETURN_ERROR);
 		src_w = src_wl->window;
 	}
+	server_unzoom_window(src_w);
 
 	if (src_wp == dst_wp)
 		return (CMD_RETURN_NORMAL);

input-keys.c

@@ -218,7 +218,8 @@ input_mouse(struct window_pane *wp, struct session *s, struct mouse_event *m)
 		 */
 		if (m->sgr && (wp->screen->mode & MODE_MOUSE_SGR)) {
 			len = xsnprintf(buf, sizeof buf, "\033[<%d;%d;%d%c",
-			    m->sgr_xb, m->x + 1, m->y + 1, m->sgr_rel ? 'm' : 'M');
+			    m->sgr_xb, m->x + 1, m->y + 1,
+			    m->sgr_rel ? 'm' : 'M');
 		} else if (wp->screen->mode & MODE_MOUSE_UTF8) {
 			len = xsnprintf(buf, sizeof buf, "\033[M");
 			len += utf8_split2(m->xb + 32, &buf[len]);

key-bindings.c

@@ -150,6 +150,7 @@ key_bindings_init(void)
 		{ 't', 			  0, &cmd_clock_mode_entry },
 		{ 'w', 			  0, &cmd_choose_window_entry },
 		{ 'x', 			  0, &cmd_confirm_before_entry },
+		{ 'z',			  0, &cmd_resize_pane_entry },
 		{ '{',			  0, &cmd_swap_pane_entry },
 		{ '}',			  0, &cmd_swap_pane_entry },
 		{ '~',			  0, &cmd_show_messages_entry },

layout.c

@@ -374,13 +374,13 @@ layout_destroy_cell(struct layout_cell *lc, struct layout_cell **lcroot)
 }
 
 void
-layout_init(struct window *w)
+layout_init(struct window *w, struct window_pane *wp)
 {
 	struct layout_cell	*lc;
 
 	lc = w->layout_root = layout_create_cell(NULL);
 	layout_set_size(lc, w->sx, w->sy, 0, 0);
-	layout_make_leaf(lc, TAILQ_FIRST(&w->panes));
+	layout_make_leaf(lc, wp);
 
 	layout_fix_panes(w, w->sx, w->sy);
 }

resize.c

@@ -50,7 +50,7 @@ recalculate_sizes(void)
 	struct window		*w;
 	struct window_pane	*wp;
 	u_int			 i, j, ssx, ssy, has, limit;
-	int			 flag, has_status;
+	int			 flag, has_status, is_zoomed;
 
 	RB_FOREACH(s, sessions, &sessions) {
 		has_status = options_get_number(&s->options, "status");
@@ -123,12 +123,16 @@ recalculate_sizes(void)
 
 		if (w->sx == ssx && w->sy == ssy)
 			continue;
-
 		log_debug("window size %u,%u (was %u,%u)", ssx, ssy, w->sx,
 		    w->sy);
 
+		is_zoomed = w->flags & WINDOW_ZOOMED;
+		if (is_zoomed)
+			window_unzoom(w);
 		layout_resize(w, ssx, ssy);
 		window_resize(w, ssx, ssy);
+		if (is_zoomed && window_pane_visible(w->active))
+			window_zoom(w->active);
 
 		/*
 		 * If the current pane is now not visible, move to the next

server-client.c

@@ -383,6 +383,7 @@ server_client_handle_key(struct client *c, int key)
 	if (c->flags & CLIENT_IDENTIFY && key >= '0' && key <= '9') {
 		if (c->flags & CLIENT_READONLY)
 			return;
+		window_unzoom(w);
 		wp = window_pane_at_index(w, key - '0');
 		if (wp != NULL && window_pane_visible(wp))
 			window_set_active_pane(w, wp);

server-fn.c

@@ -377,6 +377,7 @@ server_destroy_pane(struct window_pane *wp)
 		return;
 	}
 
+	server_unzoom_window(w);
 	layout_close_pane(wp);
 	window_remove_pane(w, wp);
 
@@ -588,3 +589,11 @@ server_set_stdin_callback(struct client *c, void (*cb)(struct client *, int,
 
 	return (0);
 }
+
+void
+server_unzoom_window(struct window *w)
+{
+	window_unzoom(w);
+	server_redraw_window(w);
+	server_status_window(w);
+}

tmux.1

@@ -1572,7 +1572,7 @@ Rename the current window, or the window at
 if specified, to
 .Ar new-name .
 .It Xo Ic resize-pane
-.Op Fl DLRU
+.Op Fl DLRUZ
 .Op Fl t Ar target-pane
 .Op Fl x Ar width
 .Op Fl y Ar height
@@ -1596,6 +1596,11 @@ or
 The
 .Ar adjustment
 is given in lines or cells (the default is 1).
+.Pp
+With
+.Fl Z ,
+the active pane is toggled between occupying the whole of the window and it's
+normal position in the layout.
 .It Xo Ic respawn-pane
 .Op Fl k
 .Op Fl t Ar target-pane

tmux.h

@@ -925,7 +925,9 @@ struct window_pane {
 	u_int		 id;
 
 	struct window	*window;
+
 	struct layout_cell *layout_cell;
+	struct layout_cell *saved_layout_cell;
 
 	u_int		 sx;
 	u_int		 sy;
@@ -990,6 +992,7 @@ struct window {
 
 	int		 lastlayout;
 	struct layout_cell *layout_root;
+	struct layout_cell *saved_layout_root;
 
 	u_int		 sx;
 	u_int		 sy;
@@ -999,6 +1002,7 @@ struct window {
 #define WINDOW_ACTIVITY 0x2
 #define WINDOW_REDRAW 0x4
 #define WINDOW_SILENCE 0x8
+#define WINDOW_ZOOMED 0x10
 
 	struct options	 options;
 
@@ -1925,6 +1929,7 @@ void	 server_push_stdout(struct client *);
 void	 server_push_stderr(struct client *);
 int	 server_set_stdin_callback(struct client *, void (*)(struct client *,
 	     int, void *), void *, char **);
+void	 server_unzoom_window(struct window *);
 
 /* status.c */
 int	 status_out_cmp(struct status_out *, struct status_out *);
@@ -2128,6 +2133,8 @@ struct window_pane *window_find_string(struct window *, const char *);
 void		 window_set_active_pane(struct window *, struct window_pane *);
 struct window_pane *window_add_pane(struct window *, u_int);
 void		 window_resize(struct window *, u_int, u_int);
+int		 window_zoom(struct window_pane *);
+int		 window_unzoom(struct window *);
 void		 window_remove_pane(struct window *, struct window_pane *);
 struct window_pane *window_pane_at_index(struct window *, u_int);
 struct window_pane *window_pane_next_by_number(struct window *,
@@ -2184,7 +2191,7 @@ void		 layout_fix_panes(struct window *, u_int, u_int);
 u_int		 layout_resize_check(struct layout_cell *, enum layout_type);
 void		 layout_resize_adjust(
 		     struct layout_cell *, enum layout_type, int);
-void		 layout_init(struct window *);
+void		 layout_init(struct window *, struct window_pane *);
 void		 layout_free(struct window *);
 void		 layout_resize(struct window *, u_int, u_int);
 void		 layout_resize_pane(struct window_pane *, enum layout_type,

window.c

@@ -316,7 +316,7 @@ window_create(const char *name, const char *cmd, const char *shell,
 
 	w = window_create1(sx, sy);
 	wp = window_add_pane(w, hlimit);
-	layout_init(w);
+	layout_init(w, wp);
 
 	if (*cmd != '\0') {
 		prefix = options_get_string(&w->options, "command-prefix");
@@ -345,6 +345,8 @@ window_destroy(struct window *w)
 {
 	u_int	i;
 
+	window_unzoom(w);
+
 	if (window_index(w, &i) != 0)
 		fatalx("index not found");
 	ARRAY_SET(&windows, i, NULL);
@@ -467,6 +469,54 @@ window_find_string(struct window *w, const char *s)
 	return (window_get_active_at(w, x, y));
 }
 
+int
+window_zoom(struct window_pane *wp)
+{
+	struct window		*w = wp->window;
+	struct window_pane	*wp1;
+
+	if (w->flags & WINDOW_ZOOMED)
+		return (-1);
+
+	if (!window_pane_visible(wp))
+		return (-1);
+	if (w->active != wp)
+		window_set_active_pane(w, wp);
+
+	TAILQ_FOREACH(wp1, &w->panes, entry) {
+		wp1->saved_layout_cell = wp1->layout_cell;
+		wp1->layout_cell = NULL;
+	}
+
+	w->saved_layout_root = w->layout_root;
+	layout_init(w, wp);
+	w->flags |= WINDOW_ZOOMED;
+
+	return (0);
+}
+
+int
+window_unzoom(struct window *w)
+{
+	struct window_pane	*wp, *wp1;
+
+	if (!(w->flags & WINDOW_ZOOMED))
+		return (-1);
+	wp = w->active;
+
+	w->flags &= ~WINDOW_ZOOMED;
+	layout_free(w);
+	w->layout_root = w->saved_layout_root;
+
+	TAILQ_FOREACH(wp1, &w->panes, entry) {
+		wp1->layout_cell = wp1->saved_layout_cell;
+		wp1->saved_layout_cell = NULL;
+	}
+	layout_fix_panes(w, w->sx, w->sy);
+
+	return (0);
+}
+
 struct window_pane *
 window_add_pane(struct window *w, u_int hlimit)
 {
@@ -597,6 +647,8 @@ window_printable_flags(struct session *s, struct winlink *wl)
 		flags[pos++] = '*';
 	if (wl == TAILQ_FIRST(&s->lastw))
 		flags[pos++] = '-';
+	if (wl->window->flags & WINDOW_ZOOMED)
+		flags[pos++] = 'Z';
 	if (pos == 0)
 		flags[pos++] = ' ';
 	flags[pos] = '\0';
@@ -1030,6 +1082,8 @@ window_pane_visible(struct window_pane *wp)
 {
 	struct window	*w = wp->window;
 
+	if (wp->layout_cell == NULL)
+		return (0);
 	if (wp->xoff >= w->sx || wp->yoff >= w->sy)
 		return (0);
 	if (wp->xoff + wp->sx > w->sx || wp->yoff + wp->sy > w->sy)