Support for windows larger than the client.

This adds two new options, window-size and default-size, and a new
command, resize-window.

The force-width and force-height options, and the session_width and
session_height formats have been removed.

The new window-size option tells tmux how to work out the size of
windows: largest means it picks the size of the largest session,
smallest the smallest session (similar to the old behaviour) and
manual means that it does not automatically resize
windows. aggressive-resize modifies the choice of session for largest
and smallest as it did before.

If a window is in a session attached to a client that is too small,
only part of the window is shown. tmux attempts to keep the cursor
visible, so the part of the window displayed is changed as the cursor
moves (with a small delay, to try and avoid excess redrawing when
applications redraw status lines or similar that are not currently
visible).

Drawing windows which are larger than the client is not as efficient
as those which fit, particularly when the cursor moves, so it is
recommended to avoid using this on slow machines or networks (set
window-size to smallest or manual).

The resize-window command can be used to resize a window manually. If
it is used, the window-size option is automatically set to manual for
the window (undo this with "setw -u window-size"). resize-window works
in a similar way to resize-pane (-U -D -L -R -x -y flags) but also has
-a and -A flags. -a sets the window to the size of the smallest client
(what it would be if window-size was smallest) and -A the largest.

For the same behaviour as force-width or force-height, use
resize-width -x or -y.

If the global window-size option is set to manual, the default-size
option is used for new windows. If -x or -y is used with new-session,
that sets the default-size option for the new session.

The maximum size of a window is 10000x10000. But expect applications
to complain and higher memory use if you make a window that big. The
minimum size is the size required for the current layout including
borders.

This change allows some code improvements, most notably that since
windows can now never be cropped, that code can be removed from the
layout code, and since panes can now never be outside the size of the
window, window_pane_visible can be removed.

1 files changed, 92 insertions, 50 deletions

diff --git a/screen-write.c b/screen-write.c
index fac5229e..b9db16a9 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -54,6 +54,41 @@ struct screen_write_collect_line {
 	TAILQ_HEAD(, screen_write_collect_item) items;
 };
 
+static void
+screen_write_offset_timer(__unused int fd, __unused short events, void *data)
+{
+	struct window	*w = data;
+
+	tty_update_window_offset(w);
+}
+
+/* Set cursor position. */
+static void
+screen_write_set_cursor(struct screen_write_ctx *ctx, int cx, int cy)
+{
+	struct window_pane	*wp = ctx->wp;
+	struct window		*w;
+	struct screen		*s = ctx->s;
+	struct timeval		 tv = { .tv_usec = 10000 };
+
+	if (cx != -1 && (u_int)cx == s->cx && cy != -1 && (u_int)cy == s->cy)
+		return;
+
+	if (cx != -1)
+		s->cx = cx;
+	if (cy != -1)
+		s->cy = cy;
+
+	if (wp == NULL)
+		return;
+	w = wp->window;
+
+	if (!event_initialized(&w->offset_timer))
+		evtimer_set(&w->offset_timer, screen_write_offset_timer, w);
+	if (!evtimer_pending(&w->offset_timer, NULL))
+		evtimer_add(&w->offset_timer, &tv);
+}
+
 /* Initialize writing with a window. */
 void
 screen_write_start(struct screen_write_ctx *ctx, struct window_pane *wp,
@@ -603,25 +638,26 @@ void
 screen_write_cursorup(struct screen_write_ctx *ctx, u_int ny)
 {
 	struct screen	*s = ctx->s;
+	u_int		 cx = s->cx, cy = s->cy;
 
 	if (ny == 0)
 		ny = 1;
 
-	if (s->cy < s->rupper) {
+	if (cy < s->rupper) {
 		/* Above region. */
-		if (ny > s->cy)
-			ny = s->cy;
+		if (ny > cy)
+			ny = cy;
 	} else {
 		/* Below region. */
-		if (ny > s->cy - s->rupper)
-			ny = s->cy - s->rupper;
+		if (ny > cy - s->rupper)
+			ny = cy - s->rupper;
 	}
-	if (s->cx == screen_size_x(s))
-	    s->cx--;
-	if (ny == 0)
-		return;
+	if (cx == screen_size_x(s))
+		cx--;
+
+	cy -= ny;
 
-	s->cy -= ny;
+	screen_write_set_cursor(ctx, cx, cy);
 }
 
 /* Cursor down by ny. */
@@ -629,25 +665,28 @@ void
 screen_write_cursordown(struct screen_write_ctx *ctx, u_int ny)
 {
 	struct screen	*s = ctx->s;
+	u_int		 cx = s->cx, cy = s->cy;
 
 	if (ny == 0)
 		ny = 1;
 
-	if (s->cy > s->rlower) {
+	if (cy > s->rlower) {
 		/* Below region. */
-		if (ny > screen_size_y(s) - 1 - s->cy)
-			ny = screen_size_y(s) - 1 - s->cy;
+		if (ny > screen_size_y(s) - 1 - cy)
+			ny = screen_size_y(s) - 1 - cy;
 	} else {
 		/* Above region. */
-		if (ny > s->rlower - s->cy)
-			ny = s->rlower - s->cy;
+		if (ny > s->rlower - cy)
+			ny = s->rlower - cy;
 	}
-	if (s->cx == screen_size_x(s))
-	    s->cx--;
-	if (ny == 0)
+	if (cx == screen_size_x(s))
+	    cx--;
+	else if (ny == 0)
 		return;
 
-	s->cy += ny;
+	cy += ny;
+
+	screen_write_set_cursor(ctx, cx, cy);
 }
 
 /* Cursor right by nx. */
@@ -655,16 +694,19 @@ void
 screen_write_cursorright(struct screen_write_ctx *ctx, u_int nx)
 {
 	struct screen	*s = ctx->s;
+	u_int		 cx = s->cx, cy = s->cy;
 
 	if (nx == 0)
 		nx = 1;
 
-	if (nx > screen_size_x(s) - 1 - s->cx)
-		nx = screen_size_x(s) - 1 - s->cx;
+	if (nx > screen_size_x(s) - 1 - cx)
+		nx = screen_size_x(s) - 1 - cx;
 	if (nx == 0)
 		return;
 
-	s->cx += nx;
+	cx += nx;
+
+	screen_write_set_cursor(ctx, cx, cy);
 }
 
 /* Cursor left by nx. */
@@ -672,16 +714,19 @@ void
 screen_write_cursorleft(struct screen_write_ctx *ctx, u_int nx)
 {
 	struct screen	*s = ctx->s;
+	u_int		 cx = s->cx, cy = s->cy;
 
 	if (nx == 0)
 		nx = 1;
 
-	if (nx > s->cx)
-		nx = s->cx;
+	if (nx > cx)
+		nx = cx;
 	if (nx == 0)
 		return;
 
-	s->cx -= nx;
+	cx -= nx;
+
+	screen_write_set_cursor(ctx, cx, cy);
 }
 
 /* Backspace; cursor left unless at start of wrapped line when can move up. */
@@ -690,17 +735,20 @@ screen_write_backspace(struct screen_write_ctx *ctx)
 {
 	struct screen		*s = ctx->s;
 	struct grid_line	*gl;
+	u_int			 cx = s->cx, cy = s->cy;
 
-	if (s->cx == 0) {
-		if (s->cy == 0)
+	if (cx == 0) {
+		if (cy == 0)
 			return;
-		gl = grid_get_line(s->grid, s->grid->hsize + s->cy - 1);
+		gl = grid_get_line(s->grid, s->grid->hsize + cy - 1);
 		if (gl->flags & GRID_LINE_WRAPPED) {
-			s->cy--;
-			s->cx = screen_size_x(s) - 1;
+			cy--;
+			cx = screen_size_x(s) - 1;
 		}
 	} else
-		s->cx--;
+		cx--;
+
+	screen_write_set_cursor(ctx, cx, cy);
 }
 
 /* VT100 alignment test. */
@@ -712,8 +760,6 @@ screen_write_alignmenttest(struct screen_write_ctx *ctx)
 	struct grid_cell       	 gc;
 	u_int			 xx, yy;
 
-	screen_write_initctx(ctx, &ttyctx);
-
 	memcpy(&gc, &grid_default_cell, sizeof gc);
 	utf8_set(&gc.data, 'E');
 
@@ -722,8 +768,7 @@ screen_write_alignmenttest(struct screen_write_ctx *ctx)
 			grid_view_set_cell(s->grid, xx, yy, &gc);
 	}
 
-	s->cx = 0;
-	s->cy = 0;
+	screen_write_set_cursor(ctx, 0, 0);
 
 	s->rupper = 0;
 	s->rlower = screen_size_y(s) - 1;
@@ -988,8 +1033,7 @@ screen_write_cursormove(struct screen_write_ctx *ctx, u_int px, u_int py)
 	if (py > screen_size_y(s) - 1)
 		py = screen_size_y(s) - 1;
 
-	s->cx = px;
-	s->cy = py;
+	screen_write_set_cursor(ctx, px, py);
 }
 
 /* Reverse index (up with scroll). */
@@ -1005,7 +1049,7 @@ screen_write_reverseindex(struct screen_write_ctx *ctx, u_int bg)
 	if (s->cy == s->rupper)
 		grid_view_scroll_region_down(s->grid, s->rupper, s->rlower, bg);
 	else if (s->cy > 0)
-		s->cy--;
+		screen_write_set_cursor(ctx, -1, s->cy - 1);
 
 	screen_write_collect_flush(ctx, 0);
 	tty_write(tty_cmd_reverseindex, &ttyctx);
@@ -1028,8 +1072,7 @@ screen_write_scrollregion(struct screen_write_ctx *ctx, u_int rupper,
 	screen_write_collect_flush(ctx, 0);
 
 	/* Cursor moves to top-left. */
-	s->cx = 0;
-	s->cy = 0;
+	screen_write_set_cursor(ctx, 0, 0);
 
 	s->rupper = rupper;
 	s->rlower = rlower;
@@ -1062,7 +1105,7 @@ screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped, u_int bg)
 		screen_write_collect_scroll(ctx);
 		ctx->scrolled++;
 	} else if (s->cy < screen_size_y(s) - 1)
-		s->cy++;
+		screen_write_set_cursor(ctx, -1, s->cy + 1);
 }
 
 /* Scroll up. */
@@ -1094,9 +1137,7 @@ screen_write_scrollup(struct screen_write_ctx *ctx, u_int lines, u_int bg)
 void
 screen_write_carriagereturn(struct screen_write_ctx *ctx)
 {
-	struct screen	*s = ctx->s;
-
-	s->cx = 0;
+	screen_write_set_cursor(ctx, 0, -1);
 }
 
 /* Clear to end of screen from cursor. */
@@ -1300,14 +1341,15 @@ screen_write_collect_end(struct screen_write_ctx *ctx)
 			grid_view_set_cell(s->grid, xx, s->cy,
 			    &grid_default_cell);
 		}
-		if (gc.data.width > 1)
+		if (gc.data.width > 1) {
 			grid_view_set_cell(s->grid, xx, s->cy,
 			    &grid_default_cell);
+		}
 	}
 
 	memcpy(&gc, &ci->gc, sizeof gc);
 	grid_view_set_cells(s->grid, s->cx, s->cy, &gc, ci->data, ci->used);
-	s->cx += ci->used;
+	screen_write_set_cursor(ctx, s->cx + ci->used, -1);
 
 	for (xx = s->cx; xx < screen_size_x(s); xx++) {
 		grid_view_get_cell(s->grid, xx, s->cy, &gc);
@@ -1361,7 +1403,7 @@ screen_write_collect_add(struct screen_write_ctx *ctx,
 		log_debug("%s: wrapped at %u,%u", __func__, s->cx, s->cy);
 		ci->wrapped = 1;
 		screen_write_linefeed(ctx, 1, 8);
-		s->cx = 0;
+		screen_write_set_cursor(ctx, 0, -1);
 	}
 
 	if (ci->used == 0)
@@ -1423,7 +1465,7 @@ screen_write_cell(struct screen_write_ctx *ctx, const struct grid_cell *gc)
 	if ((s->mode & MODE_WRAP) && s->cx > sx - width) {
 		log_debug("%s: wrapped at %u,%u", __func__, s->cx, s->cy);
 		screen_write_linefeed(ctx, 1, 8);
-		s->cx = 0;
+		screen_write_set_cursor(ctx, 0, -1);
 		screen_write_collect_flush(ctx, 1);
 	}
 
@@ -1496,9 +1538,9 @@ screen_write_cell(struct screen_write_ctx *ctx, const struct grid_cell *gc)
 	 */
 	last = !(s->mode & MODE_WRAP);
 	if (s->cx <= sx - last - width)
-		s->cx += width;
+		screen_write_set_cursor(ctx, s->cx + width, -1);
 	else
-		s->cx = sx - last;
+		screen_write_set_cursor(ctx,  sx - last, -1);
 
 	/* Create space for character in insert mode. */
 	if (s->mode & MODE_INSERT) {