Custom layouts. list-windows command displays the layout as a string (such as

"bb62,159x48,0,0{79x48,0,0,79x48,80,0}") and it can be applied to another
window (with the same number of panes or fewer) using select-layout.

Makefile

@@ -31,7 +31,7 @@ SRCS=	attributes.c cfg.c client.c clock.c \
 	cmd-pipe-pane.c cmd-capture-pane.c cmd.c \
 	colour.c environ.c grid-view.c grid-utf8.c grid.c input-keys.c \
 	input.c key-bindings.c key-string.c \
-	layout-set.c layout-string.c layout.c log.c job.c \
+	layout-custom.c layout-set.c layout-string.c layout.c log.c job.c \
 	mode-key.c names.c options.c paste.c procname.c \
 	resize.c screen-redraw.c screen-write.c screen.c session.c status.c \
 	signal.c server-fn.c server.c server-client.c server-window.c \

cmd-list-windows.c

@@ -45,6 +45,7 @@ cmd_list_windows_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct cmd_target_data	*data = self->data;
 	struct session		*s;
 	struct winlink		*wl;
+	char			*layout;
 
 	if ((s = cmd_find_session(ctx, data->target)) == NULL)
 		return (-1);
@@ -52,6 +53,9 @@ cmd_list_windows_exec(struct cmd *self, struct cmd_ctx *ctx)
 	RB_FOREACH(wl, winlinks, &s->windows) {
 		ctx->print(ctx, "%d: %s [%ux%u]",
 		    wl->idx, wl->window->name, wl->window->sx, wl->window->sy);
+		layout = layout_dump(wl->window);
+		ctx->print(ctx, "    layout: %s", layout);
+		xfree(layout);
 	}
 
 	return (0);

cmd-select-layout.c

@@ -79,13 +79,16 @@ cmd_select_layout_exec(struct cmd *self, struct cmd_ctx *ctx)
 		layout = wl->window->lastlayout;
 		if (layout == -1)
 			return (0);
-	} else if ((layout = layout_set_lookup(data->arg)) == -1) {
-		ctx->error(ctx, "unknown layout or ambiguous: %s", data->arg);
-		return (-1);
-	}
-
+	} else if ((layout = layout_set_lookup(data->arg)) != -1) {
 		layout = layout_set_select(wl->window, layout);
 		ctx->info(ctx, "arranging in: %s", layout_set_name(layout));
+	} else {
+		if (layout_parse(wl->window, data->arg) == -1) {
+			ctx->error(ctx, "can't set layout: %s", data->arg);
+			return (-1);
+		}
+		ctx->info(ctx, "arranging in: %s", data->arg);
+	}
 
 	return (0);
 }

layout-custom.c

@@ -0,0 +1,264 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2010 Nicholas Marriott <nicm@users.sourceforge.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <ctype.h>
+#include <string.h>
+
+#include "tmux.h"
+
+u_short			layout_checksum(const char *);
+int			layout_append(struct layout_cell *, char *, size_t);
+struct layout_cell     *layout_construct(struct layout_cell *, const char **);
+void			layout_assign(struct window_pane **, struct layout_cell *);
+
+/* Calculate layout checksum. */
+u_short
+layout_checksum(const char *layout)
+{
+	u_short	csum;
+
+	csum = 0;
+	for (; *layout != '\0'; layout++) {
+		csum = (csum >> 1) + ((csum & 1) << 15);
+		csum += *layout;
+	}
+	return (csum);
+}
+
+/* Dump layout as a string. */
+char *
+layout_dump(struct window *w)
+{
+	char	layout[BUFSIZ], *out;
+
+	*layout = '\0';
+	if (layout_append(w->layout_root, layout, sizeof layout) != 0)
+		return (NULL);
+
+	xasprintf(&out, "%4x,%s", layout_checksum(layout), layout);
+	return (out);
+}
+
+/* Append information for a single cell. */
+int
+layout_append(struct layout_cell *lc, char *buf, size_t len)
+{
+	struct layout_cell     *lcchild;
+	char			tmp[64];
+	size_t			tmplen;
+	const char	       *brackets = "][";
+
+	if (len == 0)
+		return (-1);
+
+	tmplen = xsnprintf(tmp, sizeof tmp,
+	    "%ux%u,%u,%u", lc->sx, lc->sy, lc->xoff, lc->yoff);
+	if (tmplen > (sizeof tmp) - 1)
+		return (-1);
+	if (strlcat(buf, tmp, len) >= len)
+		return (-1);
+
+	switch (lc->type) {
+	case LAYOUT_LEFTRIGHT:
+		brackets = "}{";
+		/* FALLTHROUGH */
+	case LAYOUT_TOPBOTTOM:
+		if (strlcat(buf, &brackets[1], len) >= len)
+			return (-1);
+		TAILQ_FOREACH(lcchild, &lc->cells, entry) {
+			if (layout_append(lcchild, buf, len) != 0)
+				return (-1);
+			if (strlcat(buf, ",", len) >= len)
+				return (-1);
+		}
+		buf[strlen(buf) - 1] = brackets[0];
+		break;
+	case LAYOUT_WINDOWPANE:
+		break;
+	}
+
+	return (0);
+}
+
+/* Parse a layout string and arrange window as layout. */
+int
+layout_parse(struct window *w, const char *layout)
+{
+	struct layout_cell	*lc, *lcchild;
+	struct window_pane	*wp;
+	u_int			 npanes, ncells, sx, sy;
+	u_short			 csum;
+
+	/* Check validity. */
+	if (sscanf(layout, "%hx,", &csum) != 1)
+		return (-1);
+	layout += 5;
+	if (csum != layout_checksum(layout))
+		return (-1);
+
+	/* Build the layout. */
+	lc = layout_construct(NULL, &layout);
+	if (lc == NULL)
+		return (-1);
+	if (*layout != '\0')
+		goto fail;
+
+	/* Check this window will fit into the layout. */
+	for (;;) {
+		npanes = window_count_panes(w);
+		ncells = layout_count_cells(lc);
+		if (npanes > ncells)
+			goto fail;
+		if (npanes == ncells)
+			break;
+
+		/* Fewer panes than cells - close the bottom right. */
+		lcchild = layout_find_bottomright(lc);
+		layout_destroy_cell(lcchild, &lc);
+	}
+
+	/* Save the old window size and resize to the layout size. */
+	sx = w->sx; sy = w->sy;
+	window_resize(w, lc->sx, lc->sy);
+
+	/* Destroy the old layout and swap to the new. */
+	layout_free_cell(w->layout_root);
+	w->layout_root = lc;
+
+	/* Assign the panes into the cells. */
+	wp = TAILQ_FIRST(&w->panes);
+	layout_assign(&wp, lc);
+
+	/* Update pane offsets and sizes. */
+	layout_fix_offsets(lc);
+	layout_fix_panes(w, lc->sx, lc->sy);
+
+	/* Then resize the layout back to the original window size. */
+	layout_resize(w, sx, sy);
+	window_resize(w, sx, sy);
+
+	layout_print_cell(lc, __func__, 0);
+
+	return (0);
+
+fail:
+	layout_free_cell(lc);
+	return (-1);
+}
+
+/* Assign panes into cells. */
+void
+layout_assign(struct window_pane **wp, struct layout_cell *lc)
+{
+	struct layout_cell	*lcchild;
+
+	switch (lc->type) {
+	case LAYOUT_WINDOWPANE:
+		layout_make_leaf(lc, *wp);
+		*wp = TAILQ_NEXT(*wp, entry);
+		return;
+	case LAYOUT_LEFTRIGHT:
+	case LAYOUT_TOPBOTTOM:
+		TAILQ_FOREACH(lcchild, &lc->cells, entry)
+			layout_assign(wp, lcchild);
+		return;
+	}
+}
+
+/* Construct a cell from all or part of a layout tree. */
+struct layout_cell *
+layout_construct(struct layout_cell *lcparent, const char **layout)
+{
+	struct layout_cell     *lc, *lcchild;
+	u_int			sx, sy, xoff, yoff;
+
+	if (!isdigit((u_char) **layout))
+		return (NULL);
+	if (sscanf(*layout, "%ux%u,%u,%u", &sx, &sy, &xoff, &yoff) != 4)
+		return (NULL);
+
+	while (isdigit((u_char) **layout))
+		(*layout)++;
+	if (**layout != 'x')
+		return (NULL);
+	(*layout)++;
+	while (isdigit((u_char) **layout))
+		(*layout)++;
+	if (**layout != ',')
+		return (NULL);
+	(*layout)++;
+	while (isdigit((u_char) **layout))
+		(*layout)++;
+	if (**layout != ',')
+		return (NULL);
+	(*layout)++;
+	while (isdigit((u_char) **layout))
+		(*layout)++;
+
+	lc = layout_create_cell(lcparent);
+	lc->sx = sx;
+	lc->sy = sy;
+	lc->xoff = xoff;
+	lc->yoff = yoff;
+
+	switch (**layout) {
+	case ',':
+	case '}':
+	case ']':
+	case '\0':
+		return (lc);
+	case '{':
+		lc->type = LAYOUT_LEFTRIGHT;
+		break;
+	case '[':
+		lc->type = LAYOUT_TOPBOTTOM;
+		break;
+	default:
+		goto fail;
+	}
+
+	do {
+		(*layout)++;
+		lcchild = layout_construct(lc, layout);
+		if (lcchild == NULL)
+			goto fail;
+		TAILQ_INSERT_TAIL(&lc->cells, lcchild, entry);
+	} while (**layout == ',');
+
+	switch (lc->type) {
+	case LAYOUT_LEFTRIGHT:
+		if (**layout != '}')
+			goto fail;
+		break;
+	case LAYOUT_TOPBOTTOM:
+		if (**layout != ']')
+			goto fail;
+		break;
+	default:
+		goto fail;
+	}
+	(*layout)++;
+
+	return (lc);
+
+fail:
+	layout_free_cell(lc);
+	return (NULL);
+}

layout-string.c

@@ -36,7 +36,6 @@ struct layout_cell *layout_find_right(struct layout_cell *);
 struct layout_cell *layout_find_topleft(struct layout_cell *);
 struct layout_cell *layout_find_topright(struct layout_cell *);
 struct layout_cell *layout_find_bottomleft(struct layout_cell *);
-struct layout_cell *layout_find_bottomright(struct layout_cell *);
 
 /* Find the cell; returns NULL if string not understood. */
 struct layout_cell *

layout.c

@@ -218,6 +218,27 @@ layout_fix_panes(struct window *w, u_int wsx, u_int wsy)
 	}
 }
 
+/* Count the number of available cells in a layout. */
+u_int
+layout_count_cells(struct layout_cell *lc)
+{
+	struct layout_cell	*lcchild;
+	u_int			 n;
+
+	switch (lc->type) {
+	case LAYOUT_WINDOWPANE:
+		return (1);
+	case LAYOUT_LEFTRIGHT:
+	case LAYOUT_TOPBOTTOM:
+		n = 0;
+		TAILQ_FOREACH(lcchild, &lc->cells, entry)
+			n += layout_count_cells(lcchild);
+		return (n);
+	default:
+		fatalx("bad layout type");
+	}
+}
+
 /* Calculate how much size is available to be removed from a cell. */
 u_int
 layout_resize_check(struct layout_cell *lc, enum layout_type type)
@@ -302,6 +323,56 @@ layout_resize_adjust(struct layout_cell *lc, enum layout_type type, int change)
 	}
 }
 
+/* Destroy a cell and redistribute the space. */
+void
+layout_destroy_cell(struct layout_cell *lc, struct layout_cell **lcroot)
+{
+	struct layout_cell     *lcother, *lcparent;
+
+	/*
+	 * If no parent, this is the last pane so window close is imminent and
+	 * there is no need to resize anything.
+	 */
+	lcparent = lc->parent;
+	if (lcparent == NULL) {
+		layout_free_cell(lc);
+		*lcroot = NULL;
+		return;
+	}
+
+	/* Merge the space into the previous or next cell. */
+	if (lc == TAILQ_FIRST(&lcparent->cells))
+		lcother = TAILQ_NEXT(lc, entry);
+	else
+		lcother = TAILQ_PREV(lc, layout_cells, entry);
+	if (lcparent->type == LAYOUT_LEFTRIGHT)
+		layout_resize_adjust(lcother, lcparent->type, lc->sx + 1);
+	else
+		layout_resize_adjust(lcother, lcparent->type, lc->sy + 1);
+
+	/* Remove this from the parent's list. */
+	TAILQ_REMOVE(&lcparent->cells, lc, entry);
+	layout_free_cell(lc);
+
+	/*
+	 * If the parent now has one cell, remove the parent from the tree and
+	 * replace it by that cell.
+	 */
+	lc = TAILQ_FIRST(&lcparent->cells);
+	if (TAILQ_NEXT(lc, entry) == NULL) {
+		TAILQ_REMOVE(&lcparent->cells, lc, entry);
+
+		lc->parent = lcparent->parent;
+		if (lc->parent == NULL) {
+			lc->xoff = 0; lc->yoff = 0;
+			*lcroot = lc;
+		} else
+			TAILQ_REPLACE(&lc->parent->cells, lcparent, lc, entry);
+
+		layout_free_cell(lcparent);
+	}
+}
+
 void
 layout_init(struct window *w)
 {
@@ -597,59 +668,16 @@ layout_split_pane(struct window_pane *wp, enum layout_type type, int size)
 	return (lcnew);
 }
 
-/* Destroy the layout associated with a pane and redistribute the space. */
+/* Destroy the cell associated with a pane. */
 void
 layout_close_pane(struct window_pane *wp)
 {
-	struct layout_cell     *lc, *lcother, *lcparent;
-
-	lc = wp->layout_cell;
-	lcparent = lc->parent;
-
-	/*
-	 * If no parent, this is the last pane so window close is imminent and
-	 * there is no need to resize anything.
-	 */
-	if (lcparent == NULL) {
-		layout_free_cell(lc);
-		wp->window->layout_root = NULL;
-		return;
-	}
-
-	/* Merge the space into the previous or next cell. */
-	if (lc == TAILQ_FIRST(&lcparent->cells))
-		lcother = TAILQ_NEXT(lc, entry);
-	else
-		lcother = TAILQ_PREV(lc, layout_cells, entry);
-	if (lcparent->type == LAYOUT_LEFTRIGHT)
-		layout_resize_adjust(lcother, lcparent->type, lc->sx + 1);
-	else
-		layout_resize_adjust(lcother, lcparent->type, lc->sy + 1);
-
-	/* Remove this from the parent's list. */
-	TAILQ_REMOVE(&lcparent->cells, lc, entry);
-	layout_free_cell(lc);
-
-	/*
-	 * If the parent now has one cell, remove the parent from the tree and
-	 * replace it by that cell.
-	 */
-	lc = TAILQ_FIRST(&lcparent->cells);
-	if (TAILQ_NEXT(lc, entry) == NULL) {
-		TAILQ_REMOVE(&lcparent->cells, lc, entry);
-
-		lc->parent = lcparent->parent;
-		if (lc->parent == NULL) {
-			lc->xoff = 0; lc->yoff = 0;
-			wp->window->layout_root = lc;
-		} else
-			TAILQ_REPLACE(&lc->parent->cells, lcparent, lc, entry);
-
-		layout_free_cell(lcparent);
-	}
+	/* Remove the cell. */
+	layout_destroy_cell(wp->layout_cell, &wp->window->layout_root);
 
 	/* Fix pane offsets and sizes. */
+	if (wp->window->layout_root != NULL) {
 		layout_fix_offsets(wp->window->layout_root);
 		layout_fix_panes(wp->window, wp->window->sx, wp->window->sy);
 	}
-
+}

tmux.1

@@ -877,6 +877,24 @@ Panes are spread out as evenly as possible over the window in both rows and
 columns.
 .El
 .Pp
+In addition,
+.Ic select-layout
+may be used to apply a previously used layout - the
+.Ic list-windows
+command displays the layout of each window in a form suitable for use with
+.Ic select-layout .
+For example:
+.Bd -literal -offset indent
+$ tmux list-windows
+0: ksh [159x48]
+    layout: bb62,159x48,0,0{79x48,0,0,79x48,80,0}
+$ tmux select-layout bb62,159x48,0,0{79x48,0,0,79x48,80,0}
+.Ed
+.Nm
+automatically adjusts the size of the layout for the current window size.
+Note that a layout cannot be applied to a window with more panes than that
+from which the layout was originally defined.
+.Pp
 Commands related to windows and panes are as follows:
 .Bl -tag -width Ds
 .It Xo Ic break-pane
@@ -1224,7 +1242,7 @@ or downward (numerically higher).
 Choose a specific layout for a window.
 If
 .Ar layout-name
-is not given, the last layout used (if any) is reapplied.
+is not given, the last preset layout used (if any) is reapplied.
 .It Xo Ic select-pane
 .Op Fl DLRU
 .Op Fl t Ar target-pane

tmux.h

@@ -1850,9 +1850,11 @@ struct window_pane *window_pane_find_left(struct window_pane *);
 struct window_pane *window_pane_find_right(struct window_pane *);
 
 /* layout.c */
+u_int		 layout_count_cells(struct layout_cell *);
 struct layout_cell *layout_create_cell(struct layout_cell *);
 void		 layout_free_cell(struct layout_cell *);
 void		 layout_print_cell(struct layout_cell *, const char *, u_int);
+void		 layout_destroy_cell(struct layout_cell *, struct layout_cell **);
 void		 layout_set_size(
 		     struct layout_cell *, u_int, u_int, u_int, u_int);
 void		 layout_make_leaf(
@@ -1873,6 +1875,10 @@ struct layout_cell *layout_split_pane(
 		     struct window_pane *, enum layout_type, int);
 void		 layout_close_pane(struct window_pane *);
 
+/* layout-custom.c */
+char		*layout_dump(struct window *);
+int		 layout_parse(struct window *, const char *);
+
 /* layout-set.c */
 const char	*layout_set_name(u_int);
 int		 layout_set_lookup(const char *);
@@ -1883,6 +1889,7 @@ void		 layout_set_active_changed(struct window *);
 
 /* layout-string.c */
 struct layout_cell *layout_find_string(struct window *, const char *);
+struct layout_cell *layout_find_bottomright(struct layout_cell *);
 
 /* window-clock.c */
 extern const struct window_mode window_clock_mode;