From: Kirill A. Korinsky <kirill@korins.ky>
Subject: Re: bin/ksh: series of patches which fixes wrong terminal width and UTF-8
To: tech@openbsd.org
Date: Tue, 20 Oct 2026 00:17:16 +0200

On Wed, 09 Sep 2026 13:23:01 +0200,
Stuart Henderson <stu@spacehopper.org> wrote:
> 
> On 2026/09/09 12:55, Kirill A. Korinsky wrote:
> > On Wed, 08 Jul 2026 11:41:07 +0200,
> > Stuart Henderson <stu@spacehopper.org> wrote:
> > > 
> > > On 2026/07/07 22:42, Kirill A. Korinsky wrote:
> > > > sorry to attached pathces, and not inlined, I think it makes it review
> > > > simpler.
> > > > 
> > > > I use that pathces for last half year in emacs mode and happy with this, but
> > > > I think we should fix that bugs and commit it.
> > > > 
> > > > It should be applied as sequence.
> > > > 
> > > > Anyone willing to test it? Ok it?
> > > 
> > > I'm running this on a few machines now. It's a big improvement so far.
> > > 
> > 
> > I still would like to go this series in.
> 
> Me too.
> 
> > Here it is as one diff with regression tests.
> > 
> > I use it for months, and haven't discovered any issues.
> > 
> > This patch fixes terminal resizes which leaves emacs and vi mode using a
> > stale width, causing premature scrolling and incorrect cursor placement;
> > UTF-8 input at the window edge also produces broken characters and misplaced
> > indicators; in vi mode, multibyte input can overrun the window buffers.
> > 
> > Anyone willing to ok it?
> 
> ok sthen, FWIW
> 

shall it go in? shall I drop it?

Index: bin/ksh/edit.c
===================================================================
RCS file: /home/cvs/src/bin/ksh/edit.c,v
diff -u -p -r1.72 edit.c
--- bin/ksh/edit.c	22 May 2026 18:11:08 -0000	1.72
+++ bin/ksh/edit.c	9 Sep 2026 10:44:49 -0000
@@ -26,7 +26,8 @@ X_chars edchars;
 
 static void x_sigwinch(int);
 volatile sig_atomic_t got_sigwinch;
-static void check_sigwinch(void);
+void check_sigwinch(void);
+void (*x_resize_cb)(void);	/* callback for resize during edit */
 
 static int	x_file_glob(int, const char *, int, char ***, int);
 static char	*x_tilde_expand(const char *);
@@ -64,7 +65,7 @@ x_sigwinch(int sig)
 	got_sigwinch = 1;
 }
 
-static void
+void
 check_sigwinch(void)
 {
 	if (got_sigwinch) {
@@ -81,11 +82,16 @@ check_sigwinch(void)
 			 * see the change cause the environ doesn't change.
 			 */
 			if (ws.ws_col) {
+				int old_cols = x_cols;
+
 				x_cols = ws.ws_col < MIN_COLS ? MIN_COLS :
 				    ws.ws_col;
 
 				if ((vp = typeset("COLUMNS", 0, 0, 0, 0)))
 					setint(vp, (int64_t) ws.ws_col);
+
+				if (x_cols != old_cols && x_resize_cb)
+					(*x_resize_cb)();
 			}
 			if (ws.ws_row && (vp = typeset("LINES", 0, 0, 0, 0)))
 				setint(vp, (int64_t) ws.ws_row);
@@ -126,12 +132,14 @@ x_getc(void)
 	char c;
 	int n;
 
-	while ((n = blocking_read(STDIN_FILENO, &c, 1)) < 0 && errno == EINTR)
+	while ((n = blocking_read(STDIN_FILENO, &c, 1)) < 0 && errno == EINTR) {
+		check_sigwinch();
 		if (trap) {
 			x_mode(false);
 			runtraps(0);
 			x_mode(true);
 		}
+	}
 	if (n != 1)
 		return -1;
 	return (int) (unsigned char) c;
Index: bin/ksh/edit.h
===================================================================
RCS file: /home/cvs/src/bin/ksh/edit.h,v
diff -u -p -r1.14 edit.h
--- bin/ksh/edit.h	22 May 2026 18:11:08 -0000	1.14
+++ bin/ksh/edit.h	9 Sep 2026 10:44:49 -0000
@@ -39,6 +39,8 @@ extern X_chars edchars;
 #define XCF_COMMAND_FILE (XCF_COMMAND|XCF_FILE)
 
 /* edit.c */
+void	check_sigwinch(void);
+extern void (*x_resize_cb)(void);
 int	x_getc(void);
 void	x_flush(void);
 int	x_putc(int);
Index: bin/ksh/emacs.c
===================================================================
RCS file: /home/cvs/src/bin/ksh/emacs.c,v
diff -u -p -r1.92 emacs.c
--- bin/ksh/emacs.c	22 May 2026 18:11:08 -0000	1.92
+++ bin/ksh/emacs.c	9 Sep 2026 10:44:49 -0000
@@ -105,6 +105,7 @@ static int	xlp_valid;
 /* end from 4.9 edit.h } */
 static	int	x_tty;		/* are we on a tty? */
 static	int	x_bind_quiet;	/* be quiet when binding keys */
+static void	x_emacs_resize(void);
 static int	(*x_last_command)(int);
 
 static	char   **x_histp;	/* history position */
@@ -129,6 +130,7 @@ static int	x_size_str(char *);
 static int	x_size(int);
 static void	x_zots(char *);
 static void	x_zotc(int);
+static void	x_zotcp(char *);
 static void	x_load_hist(char **);
 static int	x_search(char *, int, int);
 static int	x_match(char *, char *);
@@ -286,6 +288,9 @@ x_emacs(char *buf, size_t len)
 	xmp = NULL;
 	x_histp = histptr + 1;
 
+	x_resize_cb = NULL;
+	check_sigwinch();
+	x_resize_cb = x_emacs_resize;
 	xx_cols = x_cols;
 	x_col = promptlen(prompt, &p);
 	prompt_skip = p - prompt;
@@ -316,8 +321,11 @@ x_emacs(char *buf, size_t len)
 	x_last_command = NULL;
 	while (1) {
 		x_flush();
-		if ((at = x_e_getu8(line, at)) < 0)
+		if ((at = x_e_getu8(line, at)) < 0) {
+			x_resize_cb = NULL;
 			return 0;
+		}
+
 		ntries++;
 
 		if (x_arg == -1) {
@@ -378,6 +386,7 @@ x_emacs(char *buf, size_t len)
 				x_last_command = NULL;
 			break;
 		case KEOL:
+			x_resize_cb = NULL;
 			ret = xep - xbuf;
 			return (ret);
 			break;
@@ -635,16 +644,17 @@ x_fword(void)
 static void
 x_goto(char *cp)
 {
-	if (cp < xbp || cp >= (xbp + x_displen)) {
+	x_lastcp();
+	if (cp < xbp || cp > xlp) {
 		/* we are heading off screen */
 		xcp = cp;
 		x_adjust();
 	} else if (cp < xcp) {		/* move back */
 		while (cp < xcp)
-			x_bs((unsigned char)*--xcp);
+			x_bs(*--xcp);
 	} else if (cp > xcp) {		/* move forward */
 		while (cp > xcp)
-			x_zotc((unsigned char)*xcp++);
+			x_zotcp(xcp++);
 	}
 }
 
@@ -663,7 +673,7 @@ x_size_str(char *cp)
 {
 	int size = 0;
 	while (*cp)
-		size += x_size(*cp++);
+		size += x_size((unsigned char)*cp++);
 	return size;
 }
 
@@ -691,7 +701,7 @@ x_zots(char *str)
 	}
 	x_lastcp();
 	while (*str && str < xlp && adj == x_adj_done)
-		x_zotc(*str++);
+		x_zotcp(str++);
 }
 
 static void
@@ -707,6 +717,39 @@ x_zotc(int c)
 		x_e_putc(c);
 }
 
+static void
+x_zotcp(char *p)
+{
+	unsigned char uc = (unsigned char)*p;
+
+	if (uc == '\t') {
+		/*  Kludge, tabs are always four spaces.  */
+		x_e_puts("    ");
+		return;
+	}
+	if (isu8cont(uc)) {
+		if (x_col <= xx_cols) {
+			x_putc(uc);
+		}
+		if (x_adj_ok && !isu8cont((unsigned char)p[1]) &&
+		    (x_col < 0 || x_col >= (xx_cols - 2)))
+			x_adjust();
+		return;
+	}
+	if (iscntrl(uc)) {
+		x_e_putc('^');
+		x_e_putc(UNCTRL(uc));
+	} else {
+		if (x_col < xx_cols) {
+			x_putc(uc);
+			x_col++;
+		}
+		if (x_adj_ok && !isu8cont((unsigned char)p[1]) &&
+		    (x_col < 0 || x_col >= (xx_cols - 2)))
+			x_adjust();
+	}
+}
+
 static int
 x_mv_back(int c)
 {
@@ -1026,7 +1069,7 @@ x_clear_screen(int c)
 static void
 x_redraw(int limit)
 {
-	int	i, j, truncate = 0;
+	int	i, j, truncate = 0, dcols;
 	char	*cp;
 
 	x_adj_ok = 0;
@@ -1068,10 +1111,12 @@ x_redraw(int limit)
 	if (xbp != xbuf || xep > xlp)
 		limit = xx_cols;
 	if (limit >= 0) {
-		if (xep > xlp)
-			i = 0;			/* we fill the line */
-		else
-			i = limit - (xlp - xbp);
+		dcols = 0;
+		for (cp = xbp; cp < xlp; cp++)
+			dcols += x_size((unsigned char)*cp);
+		i = limit - dcols;
+		if (i < 0)
+			i = 0;
 
 		for (j = 0; j < i && x_col < (xx_cols - 2); j++)
 			x_e_putc(' ');
@@ -1128,8 +1173,8 @@ x_transpose(int c)
 		 */
 		x_bs(xcp[-1]);
 		x_bs(xcp[-2]);
-		x_zotc(xcp[-1]);
-		x_zotc(xcp[-2]);
+		x_zotcp(&xcp[-1]);
+		x_zotcp(&xcp[-2]);
 		tmp = xcp[-1];
 		xcp[-1] = xcp[-2];
 		xcp[-2] = tmp;
@@ -1138,8 +1183,8 @@ x_transpose(int c)
 		 * cursor, move cursor position along one.
 		 */
 		x_bs(xcp[-1]);
-		x_zotc(xcp[0]);
-		x_zotc(xcp[-1]);
+		x_zotcp(&xcp[0]);
+		x_zotcp(&xcp[-1]);
 		tmp = xcp[-1];
 		xcp[-1] = xcp[0];
 		xcp[0] = tmp;
@@ -1802,12 +1847,22 @@ do_complete(int flags,	/* XCF_{COMMAND,F
 static void
 x_adjust(void)
 {
+	char *cp;
+	int col;
+
 	x_adj_done++;			/* flag the fact that we were called. */
 	/*
 	 * we had a problem if the prompt length > xx_cols / 2
 	 */
-	if ((xbp = xcp - (x_displen / 2)) < xbuf)
-		xbp = xbuf;
+	col = x_displen / 2;
+	cp = xcp;
+	while (cp > xbuf && col > 0) {
+		cp--;
+		while (cp > xbuf && isu8cont(*cp))
+			cp--;
+		col -= x_size((unsigned char)*cp);
+	}
+	xbp = cp;
 	xlp_valid = false;
 	x_redraw(xx_cols);
 	x_flush();
@@ -2161,9 +2216,58 @@ x_lastcp(void)
 		for (i = 0, rcp = xbp; rcp < xep && i < x_displen; rcp++)
 			i += x_size((unsigned char)*rcp);
 		xlp = rcp;
+		while (xlp < xep && isu8cont(*xlp))
+			xlp++;
 	}
 	xlp_valid = true;
 	return (xlp);
+}
+
+static void
+x_emacs_resize(void)
+{
+	int cr_done = 0, cleared = 0;
+
+#ifndef SMALL
+	if (cur_term != NULL) {
+		if (carriage_return != NULL &&
+		    tputs(carriage_return, 1, x_putc) != ERR)
+			cr_done = 1;
+		if (clr_eos != NULL &&
+		    tputs(clr_eos, 1, x_putc) != ERR)
+			cleared = 1;
+	}
+#endif
+	if (!cr_done)
+		x_putc('\r');
+	if (!cleared) {
+		x_putc('\033');
+		x_putc('[');
+		x_putc('J');
+	}
+
+	xx_cols = x_cols;
+	x_col = promptlen(prompt, NULL);
+	if (x_col > xx_cols)
+		x_col = x_col - (x_col / xx_cols) * xx_cols;
+	x_displen = xx_cols - 2 - x_col;
+	if (x_displen < 1) {
+		x_col = 0;
+		x_displen = xx_cols - 2;
+		prompt_redraw = 0;
+	} else {
+		xbp = xbuf;
+		xlp_valid = false;
+		if (xcp <= x_lastcp()) {
+			x_redraw(0);
+			x_flush();
+			return;
+		}
+	}
+
+	x_col = 0;
+	x_displen = xx_cols - 2;
+	x_adjust();
 }
 
 #endif /* EMACS */
Index: bin/ksh/vi.c
===================================================================
RCS file: /home/cvs/src/bin/ksh/vi.c,v
diff -u -p -r1.71 vi.c
--- bin/ksh/vi.c	15 Aug 2026 11:54:18 -0000	1.71
+++ bin/ksh/vi.c	9 Sep 2026 10:44:49 -0000
@@ -24,6 +24,7 @@
 
 #undef CTRL
 #define	CTRL(x)		((x) & 0x1F)	/* ASCII */
+#define UTF8_MAXBYTES	4
 
 struct edstate {
 	char	*cbuf;		/* main buffer to build the command line */
@@ -75,6 +76,8 @@ static void	vi_error(void);
 static void	vi_macro_reset(void);
 static int	x_vi_putbuf(const char *, size_t);
 static int	isu8cont(unsigned char);
+static void	x_vi_resize(void);
+static void	calc_winsize(void);
 
 #define C_	0x1		/* a valid command that isn't a M_, E_, U_ */
 #define M_	0x2		/* movement command (h, l, etc.) */
@@ -200,6 +203,9 @@ x_vi(char *buf, size_t len)
 {
 	int	c;
 
+	x_resize_cb = NULL;
+	check_sigwinch();
+	x_resize_cb = x_vi_resize;
 	vi_reset(buf, len > LINE ? LINE : len);
 	vi_pprompt(1);
 	x_flush();
@@ -242,6 +248,7 @@ x_vi(char *buf, size_t len)
 		x_flush();
 	}
 
+	x_resize_cb = NULL;
 	x_putc('\r'); x_putc('\n'); x_flush();
 
 	if (c == -1 || len <= (size_t)es->linelen)
@@ -1363,7 +1370,7 @@ static int	prompt_trunc;		/* how much of
 static int	prompt_skip;		/* how much of prompt to skip */
 static int	winwidth;		/* available column positions */
 static char	*wbuf[2];		/* current & previous window buffer */
-static int	wbuf_len;		/* length of window buffers (x_cols-3)*/
+static int	wbuf_len;		/* length of window buffers */
 static int	win;			/* number of window buffer in use */
 static char	morec;			/* more character at right of window */
 static char	holdbuf[LINE];		/* place to hold last edit buffer */
@@ -1423,8 +1430,6 @@ free_edstate(struct edstate *old)
 static void
 edit_reset(char *buf, size_t len)
 {
-	const char *p;
-
 	es = &ebuf;
 	es->cbuf = buf;
 	es->cbufsize = len;
@@ -1435,6 +1440,18 @@ edit_reset(char *buf, size_t len)
 	es->cursor = undo->cursor = 0;
 	es->winleft = undo->winleft = 0;
 
+	calc_winsize();
+	win = 0;
+	morec = ' ';
+	holdlen = 0;
+}
+
+static void
+calc_winsize(void)
+{
+	const char *p;
+	int newlen;
+
 	cur_col = pwidth = promptlen(prompt, &p);
 	prompt_skip = p - prompt;
 	if (pwidth > x_cols - 3 - MIN_EDIT_SPACE) {
@@ -1443,17 +1460,15 @@ edit_reset(char *buf, size_t len)
 		pwidth -= prompt_trunc;
 	} else
 		prompt_trunc = 0;
-	if (!wbuf_len || wbuf_len != x_cols - 3) {
-		wbuf_len = x_cols - 3;
+	newlen = (x_cols - 3) * UTF8_MAXBYTES;
+	if (!wbuf_len || wbuf_len != newlen) {
+		wbuf_len = newlen;
 		wbuf[0] = aresize(wbuf[0], wbuf_len, APERM);
 		wbuf[1] = aresize(wbuf[1], wbuf_len, APERM);
 	}
 	(void) memset(wbuf[0], ' ', wbuf_len);
 	(void) memset(wbuf[1], ' ', wbuf_len);
 	winwidth = x_cols - pwidth - 3;
-	win = 0;
-	morec = ' ';
-	holdlen = 0;
 }
 
 /*
@@ -1870,6 +1885,7 @@ display(char *wb1, char *wb2, int leftsi
 	int	 ncol;	/* display column of the cursor */
 	int	 cnt;	/* remaining display columns to fill */
 	int	 moreright;
+	int	 trailu8;
 	char	 mc;	/* new "more character" at the right of window */
 	unsigned char ch;
 
@@ -1881,8 +1897,11 @@ display(char *wb1, char *wb2, int leftsi
 	ncol = col = 0;
 	cur = es->winleft;
 	moreright = 0;
+	trailu8 = 0;
 	twb1 = wb1;
-	while (col < winwidth && cur < es->linelen) {
+	while (cur < es->linelen &&
+	    (col < winwidth ||
+	    (col == winwidth && isu8cont(es->cbuf[cur])))) {
 		if (cur == es->cursor && leftside)
 			ncol = col + pwidth;
 		if ((ch = es->cbuf[cur]) == '\t') {
@@ -1898,7 +1917,8 @@ display(char *wb1, char *wb2, int leftsi
 				}
 				ch &= 0x7f;
 			}
-			if (col < winwidth) {
+			if (col < winwidth ||
+			    (col == winwidth && isu8cont(ch))) {
 				if (ch < ' ' || ch == 0x7f) {
 					*twb1++ = '^';
 					if (++col < winwidth) {
@@ -1906,6 +1926,8 @@ display(char *wb1, char *wb2, int leftsi
 						col++;
 					}
 				} else {
+					if (col == winwidth && isu8cont(ch))
+						trailu8 = 1;
 					*twb1++ = ch;
 					if (col == 0 || !isu8cont(ch))
 						col++;
@@ -1998,8 +2020,10 @@ display(char *wb1, char *wb2, int leftsi
 		mc = '>';
 	else
 		mc = ' ';
-	if (mc != morec) {
-		ed_mov_opt(pwidth + winwidth + 1, wb1);
+	if (mc != morec || trailu8) {
+		ed_mov_opt(pwidth + winwidth, wb1);
+		x_putc(' ');
+		cur_col++;
 		x_putc(mc);
 		cur_col++;
 		morec = mc;
@@ -2302,5 +2326,43 @@ static int
 isu8cont(unsigned char c)
 {
 	return !Flag(FVISHOW8) && (c & (0x80 | 0x40)) == 0x80;
+}
+
+static void
+x_vi_resize(void)
+{
+	int cur = 0, col = 0;
+	int cr_done = 0, cleared = 0;
+
+#ifndef SMALL
+	if (cur_term != NULL) {
+		if (carriage_return != NULL &&
+		    tputs(carriage_return, 1, x_putc) != ERR)
+			cr_done = 1;
+		if (clr_eos != NULL &&
+		    tputs(clr_eos, 1, x_putc) != ERR)
+			cleared = 1;
+	}
+#endif
+	if (!cr_done)
+		x_putc('\r');
+	if (!cleared) {
+		x_putc('\033');
+		x_putc('[');
+		x_putc('J');
+	}
+
+	calc_winsize();
+
+	while (cur < es->linelen)
+		col = newcol((unsigned char) es->cbuf[cur++], col);
+	if (col <= winwidth)
+		es->winleft = 0;
+	else if (outofwin())
+		rewindow();
+
+	redraw_line(0, 0);
+	refresh_line(insert != 0);
+	x_flush();
 }
 #endif	/* VI */
Index: regress/bin/ksh/edit/edit.c
===================================================================
RCS file: /home/cvs/src/regress/bin/ksh/edit/edit.c,v
diff -u -p -r1.8 edit.c
--- regress/bin/ksh/edit/edit.c	10 Jul 2021 07:10:31 -0000	1.8
+++ regress/bin/ksh/edit/edit.c	9 Sep 2026 10:44:49 -0000
@@ -16,6 +16,7 @@
  */
 
 #include <sys/wait.h>
+#include <sys/ioctl.h>
 
 #include <err.h>
 #include <errno.h>
@@ -49,6 +50,7 @@ main(int argc, char *argv[])
 	ssize_t		 n;
 	size_t		 nin, nprompt, nread, nwrite;
 	int		 c, nready, ptyfd, readprompt, ret, status, timeout;
+	int		 pending_resize, pending_cols, pending_quiet, pending_post;
 
 	while ((c = getopt(argc, argv, "p:")) != -1) {
 		switch (c) {
@@ -96,14 +98,20 @@ main(int argc, char *argv[])
 	}
 
 	nprompt = nread = nwrite = ret = 0;
+	pending_resize = pending_cols = pending_quiet = pending_post = 0;
 	readprompt = 1;
 	while (!gotsig) {
 		pfd.fd = ptyfd;
-		if (!readprompt && nwrite < nin)
+		if (pending_resize || pending_post) {
+			pfd.events = POLLIN;
+			timeout = WRTIM;
+		} else if (!readprompt && nwrite < nin) {
 			pfd.events = POLLOUT;
-		else
+			timeout = WRTIM;
+		} else {
 			pfd.events = POLLIN;
-		timeout = readprompt ? PRTIM : WRTIM;
+			timeout = readprompt ? PRTIM : WRTIM;
+		}
 		nready = poll(&pfd, 1, timeout);
 		if (nready == -1) {
 			if (errno == EINTR)
@@ -111,6 +119,22 @@ main(int argc, char *argv[])
 			err(1, "poll");
 		}
 		if (nready == 0) {
+			if (pending_resize) {
+				if (++pending_quiet >= 2) {
+					ws.ws_col = pending_cols;
+					if (ioctl(ptyfd, TIOCSWINSZ, &ws) == -1)
+						err(1, "ioctl TIOCSWINSZ");
+					kill(pid, SIGWINCH);
+					pending_resize = pending_cols = 0;
+					pending_quiet = 0;
+					pending_post = 1;
+				}
+				continue;
+			}
+			if (pending_post) {
+				pending_post = 0;
+				continue;
+			}
 			if (timeout == PRTIM) {
 				warnx("timeout waiting from prompt");
 				ret = 1;
@@ -136,6 +160,28 @@ main(int argc, char *argv[])
 				readprompt = 0;
 			}
 		} else if (pfd.revents & POLLOUT) {
+			if (in[nwrite] == '\0' && nwrite + 3 < nin &&
+			    in[nwrite + 1] == 'R' &&
+			    in[nwrite + 2] == 'S' &&
+			    in[nwrite + 3] >= '0' && in[nwrite + 3] <= '9') {
+				size_t i = nwrite + 3;
+				int cols = 0, nd = 0;
+
+				while (i < nin && nd < 3 &&
+				    in[i] >= '0' && in[i] <= '9') {
+					cols = cols * 10 + (in[i] - '0');
+					i++;
+					nd++;
+				}
+				if (nd > 0 && (i == nin ||
+				    in[i] < '0' || in[i] > '9') &&
+				    cols > 0) {
+					pending_resize = 1;
+					pending_cols = cols;
+					nwrite = i;
+					continue;
+				}
+			}
 			if (strchr(linefeed, in[nwrite]) != NULL)
 				readprompt = 1;
 
@@ -143,6 +189,8 @@ main(int argc, char *argv[])
 			if (n == -1)
 				err(1, "write");
 			nwrite += n;
+			if (pending_resize)
+				pending_quiet = 0;
 		}
 	}
 	close(ptyfd);
Index: regress/bin/ksh/edit/emacs.sh
===================================================================
RCS file: /home/cvs/src/regress/bin/ksh/edit/emacs.sh,v
diff -u -p -r1.15 emacs.sh
--- regress/bin/ksh/edit/emacs.sh	2 Sep 2021 07:14:15 -0000	1.15
+++ regress/bin/ksh/edit/emacs.sh	9 Sep 2026 10:44:49 -0000
@@ -52,6 +52,62 @@ testseq "z\0002\0363\0277\0277\0277" " #
 testseq "z\0002\0364\0200\0200\0200" " # z\b\0364\0200\0200\0200z\b"
 testseq "z\0002\0364\0217\0277\0277" " # z\b\0364\0217\0277\0277z\b"
 
+# ASCII resize: cols=1/11/12
+testseq "aaaaaaaaaabbbbbbbbbb\0001\000RS1" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J\r # aaaaaaa>\b\b\b\b\b\b\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\003310\0002\000RS11" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\r\033[J\raaaaabbbbb*\b\b\b\b\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\000RS12" \
+	" # aaaaaaaaaabbbbbbbbbb\r\033[J\rbbbbb     <\b\b\b\b\b\b"
+
+# ASCII resize: cols=13, cursor -1/0/+1
+testseq "aaaaaaaaaabbbbbbbbbb\003313\0002\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J\r # aaaaaaaa>\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\003312\0002\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J\r # aaaaaaaa>\b"
+testseq "aaaaaaaaaabbbbbbbbbb\003311\0002\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\r\033[J\raaaaaabbbbb*\b\b\b\b\b\b\b"
+
+# ASCII resize: cols=79/80/81
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0001\000RS79" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\rbbbbbbbbbbbbccccccccccccccccccccccccc                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J\r # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbcccccccccccccccccccccccc>\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0001\000RS80" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\rbbbbbbbbbbbbccccccccccccccccccccccccc                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0001\000RS81" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\rbbbbbbbbbbbbccccccccccccccccccccccccc                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J\r # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# ASCII window indicator at left edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 window indicator at left edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\r\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# ASCII redraw at right edge
+PS1='012345678901234567890123456789012345678901234567890123456789'
+testseq "#aaaaaaaaaaaaaaaaab\0033#" "012345678901234567890123456789012345678901234567890123456789#aaaaaaaaaaaaaaaaa\raaaaaaaaa                                                                     <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bb\r012345678901234567890123456789012345678901234567890123456789aaaaaaaaaaaaaaaaab \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 redraw at right edge
+testseq "#aaaaaaaaaaaaaaaaa\0303\0266\0033#" "012345678901234567890123456789012345678901234567890123456789#aaaaaaaaaaaaaaaaa\raaaaaaaaa                                                                     <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\0303\0266\r012345678901234567890123456789012345678901234567890123456789aaaaaaaaaaaaaaaaa\0303\0266 \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+PS1=' # '
+
+# ASCII window indicator at right edge
+testseq "\003342ab\003397b\0001" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\raaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                       <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb>\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 window indicator at right edge
+testseq "\003342a\0303\0266\003397b\0001" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\raaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                       <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb>\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# ASCII window indicator on both sides
+testseq "\003342ab\003397b\0001\003379\0006" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\raaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                       <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb>\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb*\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 window indicator on both sides
+testseq "\003342a\0303\0266\003397b\0001\003379\0006" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\raaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                         <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\rbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                       <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb>\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\ra\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb*\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
 # insertion of incomplete UTF-8
 testseq "z\0002\0302\0006" " # z\b\0302z\bz"
 testseq "z\0002\0377\0006" " # z\b\0377z\bz"
Index: regress/bin/ksh/edit/vi.sh
===================================================================
RCS file: /home/cvs/src/regress/bin/ksh/edit/vi.sh,v
diff -u -p -r1.14 vi.sh
--- regress/bin/ksh/edit/vi.sh	4 Apr 2026 09:33:18 -0000	1.14
+++ regress/bin/ksh/edit/vi.sh	9 Sep 2026 10:44:49 -0000
@@ -233,3 +233,59 @@ testseq "(x)\00330%hrc" " # (x)\b\b\b(x\
 
 # ^R: Redraw.
 testseq "test\0033h\0022" " # test\b\b\r\r\n # test\b\b"
+
+# ASCII resize: cols=1/11/12
+testseq "aaaaaaaaaabbbbbbbbbb\0033hhhhhhhhhhhhhhhhhhh\000RS1" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J# aaaaaaa >\r# "
+testseq "aaaaaaaaaabbbbbbbbbb\0033hhhhhhhhh\000RS11" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\r\033[J# aaabbbb +\b\b\b\b\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\0033\000RS12" \
+	" # aaaaaaaaaabbbbbbbbbb\b\r\033[J# bbbb    <\b\b\b\b\b\b"
+
+# ASCII resize: cols=13, cursor -1/0/+1
+testseq "aaaaaaaaaabbbbbbbbbb\0033hhhhhhhhhhhhh\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J # aaaaaaa >\b\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\0033hhhhhhhhhhhh\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J # aaaaaab +\b\b\b\b\b\b"
+testseq "aaaaaaaaaabbbbbbbbbb\0033hhhhhhhhhhh\000RS13" \
+	" # aaaaaaaaaabbbbbbbbbb\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J # aaaaabb +\b\b\b\b\b\b"
+
+# ASCII resize: cols=79/80/81
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0033hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\000RS79" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccc\r # bbbbbbbbbbbbbcccccccccccccccccccccccc                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bc\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\baaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbcccccccccccccccccccccccc >\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccc >\r # "
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0033hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\000RS80" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccc\r # bbbbbbbbbbbbbcccccccccccccccccccccccc                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bc\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\baaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbcccccccccccccccccccccccc >\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc\0033hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\000RS81" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccc\r # bbbbbbbbbbbbbcccccccccccccccccccccccc                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bc\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\baaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbcccccccccccccccccccccccc >\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r\033[J # aaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbccccccccccccccccccccccccc >\r # "
+
+# ASCII window indicator at left edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbb" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbb                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 window indicator at left edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbb" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbb\r # aaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbb                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# ASCII window indicator at right edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabb\00330" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbb\b\baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # "
+
+# UTF-8 window indicator at right edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266b\00330" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\0303\0266b\b\baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # "
+
+# ASCII window indicator on both sides
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\003340h" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\baaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                    \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbb +\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# UTF-8 window indicator on both sides
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\003340h" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\baaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbb\r # aaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb                                    \b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\r # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266bbbbbbbbbbbbbbbbbbbbbbbbbb +\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b"
+
+# ASCII redraw at right edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabb\00330\0022" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\bbb\b\baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # \r\r\n # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # "
+
+# UTF-8 redraw at right edge
+testseq "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\0303\0266b\00330\0022" \
+	" # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b                                      <\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\0303\0266b\b\baaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # \r\r\n # aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >\r # "