Add a common function for spreading out cells and use it for the two

even layouts and to add a -E flag to select-layout to spread out cells
evenly without changing parent cells.

cmd-select-layout.c

@@ -33,10 +33,10 @@ const struct cmd_entry cmd_select_layout_entry = {
 	.name = "select-layout",
 	.alias = "selectl",
 
-	.args = { "nopt:", 0, 1 },
-	.usage = "[-nop] " CMD_TARGET_WINDOW_USAGE " [layout-name]",
+	.args = { "Enopt:", 0, 1 },
+	.usage = "[-Enop] " CMD_TARGET_PANE_USAGE " [layout-name]",
 
-	.target = { 't', CMD_FIND_WINDOW, 0 },
+	.target = { 't', CMD_FIND_PANE, 0 },
 
 	.flags = CMD_AFTERHOOK,
 	.exec = cmd_select_layout_exec
@@ -71,14 +71,14 @@ const struct cmd_entry cmd_previous_layout_entry = {
 static enum cmd_retval
 cmd_select_layout_exec(struct cmd *self, struct cmdq_item *item)
 {
-	struct args	*args = self->args;
-	struct winlink	*wl = item->target.wl;
-	struct window	*w;
-	const char	*layoutname;
-	char		*oldlayout;
-	int		 next, previous, layout;
+	struct args		*args = self->args;
+	struct winlink		*wl = item->target.wl;
+	struct window		*w = wl->window;
+	struct window_pane	*wp = item->target.wp;
+	const char		*layoutname;
+	char			*oldlayout;
+	int			 next, previous, layout;
 
-	w = wl->window;
 	server_unzoom_window(w);
 
 	next = self->entry == &cmd_next_layout_entry;
@@ -99,6 +99,11 @@ cmd_select_layout_exec(struct cmd *self, struct cmdq_item *item)
 		goto changed;
 	}
 
+	if (args_has(args, 'E')) {
+		layout_spread_out(wp);
+		goto changed;
+	}
+
 	if (!args_has(args, 'o')) {
 		if (args->argc == 0)
 			layout = w->lastlayout;

key-bindings.c

@@ -186,6 +186,7 @@ key_bindings_init(void)
 		"bind = choose-buffer",
 		"bind ? list-keys",
 		"bind D choose-client",
+		"bind E select-layout -E",
 		"bind L switch-client -l",
 		"bind M select-pane -M",
 		"bind [ copy-mode",

layout-set.c

@@ -115,11 +115,11 @@ layout_set_previous(struct window *w)
 }
 
 static void
-layout_set_even_h(struct window *w)
+layout_set_even(struct window *w, enum layout_type type)
 {
 	struct window_pane	*wp;
 	struct layout_cell	*lc, *lcnew;
-	u_int			 i, n, width, xoff;
+	u_int			 n;
 
 	layout_print_cell(w->layout_root, __func__, 1);
 
@@ -128,36 +128,21 @@ layout_set_even_h(struct window *w)
 	if (n <= 1)
 		return;
 
-	/* How many can we fit? */
-	width = (w->sx - (n - 1)) / n;
-	if (width < PANE_MINIMUM)
-		width = PANE_MINIMUM;
-
 	/* Free the old root and construct a new. */
 	layout_free(w);
 	lc = w->layout_root = layout_create_cell(NULL);
 	layout_set_size(lc, w->sx, w->sy, 0, 0);
-	layout_make_node(lc, LAYOUT_LEFTRIGHT);
+	layout_make_node(lc, type);
 
 	/* Build new leaf cells. */
-	i = xoff = 0;
 	TAILQ_FOREACH(wp, &w->panes, entry) {
-		/* Create child cell. */
 		lcnew = layout_create_cell(lc);
-		layout_set_size(lcnew, width, w->sy, xoff, 0);
 		layout_make_leaf(lcnew, wp);
 		TAILQ_INSERT_TAIL(&lc->cells, lcnew, entry);
-
-		i++;
-		xoff += width + 1;
 	}
 
-	/* Allocate any remaining space. */
-	if (w->sx > xoff - 1) {
-		lc = TAILQ_LAST(&lc->cells, layout_cells);
-		layout_resize_adjust(w, lc, LAYOUT_LEFTRIGHT,
-		    w->sx - (xoff - 1));
-	}
+	/* Spread out cells. */
+	layout_spread_cell(w, lc);
 
 	/* Fix cell offsets. */
 	layout_fix_offsets(lc);
@@ -169,59 +154,16 @@ layout_set_even_h(struct window *w)
 	server_redraw_window(w);
 }
 
+static void
+layout_set_even_h(struct window *w)
+{
+	layout_set_even(w, LAYOUT_LEFTRIGHT);
+}
+
 static void
 layout_set_even_v(struct window *w)
 {
-	struct window_pane	*wp;
-	struct layout_cell	*lc, *lcnew;
-	u_int			 i, n, height, yoff;
-
-	layout_print_cell(w->layout_root, __func__, 1);
-
-	/* Get number of panes. */
-	n = window_count_panes(w);
-	if (n <= 1)
-		return;
-
-	/* How many can we fit? */
-	height = (w->sy - (n - 1)) / n;
-	if (height < PANE_MINIMUM)
-		height = PANE_MINIMUM;
-
-	/* Free the old root and construct a new. */
-	layout_free(w);
-	lc = w->layout_root = layout_create_cell(NULL);
-	layout_set_size(lc, w->sx, w->sy, 0, 0);
-	layout_make_node(lc, LAYOUT_TOPBOTTOM);
-
-	/* Build new leaf cells. */
-	i = yoff = 0;
-	TAILQ_FOREACH(wp, &w->panes, entry) {
-		/* Create child cell. */
-		lcnew = layout_create_cell(lc);
-		layout_set_size(lcnew, w->sx, height, 0, yoff);
-		layout_make_leaf(lcnew, wp);
-		TAILQ_INSERT_TAIL(&lc->cells, lcnew, entry);
-
-		i++;
-		yoff += height + 1;
-	}
-
-	/* Allocate any remaining space. */
-	if (w->sy > yoff - 1) {
-		lc = TAILQ_LAST(&lc->cells, layout_cells);
-		layout_resize_adjust(w, lc, LAYOUT_TOPBOTTOM,
-		    w->sy - (yoff - 1));
-	}
-
-	/* Fix cell offsets. */
-	layout_fix_offsets(lc);
-	layout_fix_panes(w, w->sx, w->sy);
-
-	layout_print_cell(w->layout_root, __func__, 1);
-
-	notify_window("window-layout-changed", w);
-	server_redraw_window(w);
+	layout_set_even(w, LAYOUT_TOPBOTTOM);
 }
 
 static void

layout.c

@@ -983,3 +983,61 @@ layout_close_pane(struct window_pane *wp)
 	}
 	notify_window("window-layout-changed", w);
 }
+
+int
+layout_spread_cell(struct window *w, struct layout_cell *parent)
+{
+	struct layout_cell	*lc;
+	u_int			 number, each, size;
+	int			 change, changed;
+
+	number = 0;
+	TAILQ_FOREACH (lc, &parent->cells, entry)
+	    number++;
+	if (number <= 1)
+		return (0);
+
+	if (parent->type == LAYOUT_LEFTRIGHT)
+		size = parent->sx;
+	else if (parent->type == LAYOUT_TOPBOTTOM)
+		size = parent->sy;
+	else
+		return (0);
+	each = (size - (number - 1)) / number;
+
+	changed = 0;
+	TAILQ_FOREACH (lc, &parent->cells, entry) {
+		if (TAILQ_NEXT(lc, entry) == NULL)
+			each = size - (each * (number - 1));
+		change = 0;
+		if (parent->type == LAYOUT_LEFTRIGHT) {
+			change = each - (int)lc->sx;
+			layout_resize_adjust(w, lc, LAYOUT_LEFTRIGHT, change);
+		} else if (parent->type == LAYOUT_TOPBOTTOM) {
+			change = each - (int)lc->sy;
+			layout_resize_adjust(w, lc, LAYOUT_TOPBOTTOM, change);
+		}
+		if (change != 0)
+			changed = 1;
+	}
+	return (changed);
+}
+
+void
+layout_spread_out(struct window_pane *wp)
+{
+	struct layout_cell	*parent;
+	struct window		*w = wp->window;
+
+	parent = wp->layout_cell->parent;
+	if (parent == NULL)
+		return;
+
+	do {
+		if (layout_spread_cell(w, parent)) {
+			layout_fix_offsets(parent);
+			layout_fix_panes(w, w->sx, w->sy);
+			break;
+		}
+	} while ((parent = parent->parent) != NULL);
+}

tmux.1

@@ -1923,8 +1923,8 @@ lower) with
 .Fl U
 or downward (numerically higher).
 .It Xo Ic select-layout
-.Op Fl nop
-.Op Fl t Ar target-window
+.Op Fl Enop
+.Op Fl t Ar target-pane
 .Op Ar layout-name
 .Xc
 .D1 (alias: Ic selectl )
@@ -1942,6 +1942,8 @@ and
 commands.
 .Fl o
 applies the last set layout if possible (undoes the most recent layout change).
+.Fl E
+spreads the current pane and any panes next to it out evenly.
 .It Xo Ic select-pane
 .Op Fl DdegLlMmRU
 .Op Fl P Ar style

tmux.h

@@ -2213,6 +2213,8 @@ void		 layout_assign_pane(struct layout_cell *, struct window_pane *);
 struct layout_cell *layout_split_pane(struct window_pane *, enum layout_type,
 		     int, int, int);
 void		 layout_close_pane(struct window_pane *);
+int		 layout_spread_cell(struct window *, struct layout_cell *);
+void		 layout_spread_out(struct window_pane *);
 
 /* layout-custom.c */
 char		*layout_dump(struct layout_cell *);