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Long overdue change to the way we store cells in the grid: now, instead
of storing a full grid_cell with UTF-8 data and everything, store a new
type grid_cell_entry. This can either be the cell itself (for ASCII
cells), or an offset into an extended array (per line) for UTF-8
data.

This avoid a large (8 byte) overhead on non-UTF-8 cells (by far the
majority for most users) without the complexity of the shadow array we
had before. Grid memory without any UTF-8 is about half.

The disadvantage that cells can no longer be modified in place and need
to be copied out of the grid and back but it turned out to be lot less
complicated than I expected.

/* $OpenBSD: tty.c,v 1.193 2015/11/13 08:09:28 nicm Exp $ */

/*
 * Copyright (c) 2007 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 <sys/ioctl.h>

#include <netinet/in.h>

#include <errno.h>
#include <fcntl.h>
#include <resolv.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>

#include "tmux.h"

static int tty_log_fd = -1;

void	tty_read_callback(struct bufferevent *, void *);
void	tty_error_callback(struct bufferevent *, short, void *);

void	tty_set_italics(struct tty *);
int	tty_try_256(struct tty *, u_char, const char *);

void	tty_colours(struct tty *, const struct grid_cell *);
void	tty_check_fg(struct tty *, struct grid_cell *);
void	tty_check_bg(struct tty *, struct grid_cell *);
void	tty_colours_fg(struct tty *, const struct grid_cell *);
void	tty_colours_bg(struct tty *, const struct grid_cell *);

int	tty_large_region(struct tty *, const struct tty_ctx *);
int	tty_fake_bce(const struct tty *, const struct window_pane *);
void	tty_redraw_region(struct tty *, const struct tty_ctx *);
void	tty_emulate_repeat(
	    struct tty *, enum tty_code_code, enum tty_code_code, u_int);
void	tty_repeat_space(struct tty *, u_int);
void	tty_cell(struct tty *, const struct grid_cell *,
	    const struct window_pane *);
void	tty_default_colours(struct grid_cell *, const struct window_pane *);

#define tty_use_acs(tty) \
	(tty_term_has((tty)->term, TTYC_ACSC) && !((tty)->flags & TTY_UTF8))

#define tty_pane_full_width(tty, ctx) \
	((ctx)->xoff == 0 && screen_size_x((ctx)->wp->screen) >= (tty)->sx)

void
tty_create_log(void)
{
	char	name[64];

	xsnprintf(name, sizeof name, "tmux-out-%ld.log", (long)getpid());

	tty_log_fd = open(name, O_WRONLY|O_CREAT|O_TRUNC, 0644);
	if (tty_log_fd != -1 && fcntl(tty_log_fd, F_SETFD, FD_CLOEXEC) == -1)
		fatal("fcntl failed");
}

int
tty_init(struct tty *tty, struct client *c, int fd, char *term)
{
	char	*path;

	if (!isatty(fd))
		return (-1);

	memset(tty, 0, sizeof *tty);

	if (term == NULL || *term == '\0')
		tty->termname = xstrdup("unknown");
	else
		tty->termname = xstrdup(term);
	tty->fd = fd;
	tty->client = c;

	if ((path = ttyname(fd)) == NULL)
		return (-1);
	tty->path = xstrdup(path);
	tty->cstyle = 0;
	tty->ccolour = xstrdup("");

	tty->flags = 0;
	tty->term_flags = 0;

	return (0);
}

int
tty_resize(struct tty *tty)
{
	struct winsize	ws;
	u_int		sx, sy;

	if (ioctl(tty->fd, TIOCGWINSZ, &ws) != -1) {
		sx = ws.ws_col;
		if (sx == 0)
			sx = 80;
		sy = ws.ws_row;
		if (sy == 0)
			sy = 24;
	} else {
		sx = 80;
		sy = 24;
	}
	if (!tty_set_size(tty, sx, sy))
		return (0);

	tty->cx = UINT_MAX;
	tty->cy = UINT_MAX;

	tty->rupper = UINT_MAX;
	tty->rlower = UINT_MAX;

	/*
	 * If the terminal has been started, reset the actual scroll region and
	 * cursor position, as this may not have happened.
	 */
	if (tty->flags & TTY_STARTED) {
		tty_cursor(tty, 0, 0);
		tty_region(tty, 0, tty->sy - 1);
	}

	return (1);
}

int
tty_set_size(struct tty *tty, u_int sx, u_int sy) {
	if (sx == tty->sx && sy == tty->sy)
		return (0);
	tty->sx = sx;
	tty->sy = sy;
	return (1);
}

int
tty_open(struct tty *tty, char **cause)
{
	tty->term = tty_term_find(tty->termname, tty->fd, cause);
	if (tty->term == NULL) {
		tty_close(tty);
		return (-1);
	}
	tty->flags |= TTY_OPENED;

	tty->flags &= ~(TTY_NOCURSOR|TTY_FREEZE|TTY_TIMER);

	tty->event = bufferevent_new(
	    tty->fd, tty_read_callback, NULL, tty_error_callback, tty);

	tty_start_tty(tty);

	tty_keys_build(tty);

	return (0);
}

void
tty_read_callback(unused struct bufferevent *bufev, void *data)
{
	struct tty	*tty = data;

	while (tty_keys_next(tty))
		;
}

void
tty_error_callback(
    unused struct bufferevent *bufev, unused short what, unused void *data)
{
}

void
tty_init_termios(int fd, struct termios *orig_tio, struct bufferevent *bufev)
{
	struct termios	tio;

	if (fd == -1 || tcgetattr(fd, orig_tio) != 0)
		return;

	setblocking(fd, 0);

	if (bufev != NULL)
		bufferevent_enable(bufev, EV_READ|EV_WRITE);

	memcpy(&tio, orig_tio, sizeof tio);
	tio.c_iflag &= ~(IXON|IXOFF|ICRNL|INLCR|IGNCR|IMAXBEL|ISTRIP);
	tio.c_iflag |= IGNBRK;
	tio.c_oflag &= ~(OPOST|ONLCR|OCRNL|ONLRET);
	tio.c_lflag &= ~(IEXTEN|ICANON|ECHO|ECHOE|ECHONL|ECHOCTL|
	    ECHOPRT|ECHOKE|ISIG);
	tio.c_cc[VMIN] = 1;
	tio.c_cc[VTIME] = 0;
	if (tcsetattr(fd, TCSANOW, &tio) == 0)
		tcflush(fd, TCIOFLUSH);
}

void
tty_start_tty(struct tty *tty)
{
	tty_init_termios(tty->fd, &tty->tio, tty->event);

	tty_putcode(tty, TTYC_SMCUP);

	tty_putcode(tty, TTYC_SGR0);
	memcpy(&tty->cell, &grid_default_cell, sizeof tty->cell);

	tty_putcode(tty, TTYC_RMKX);
	if (tty_use_acs(tty))
		tty_putcode(tty, TTYC_ENACS);
	tty_putcode(tty, TTYC_CLEAR);

	tty_putcode(tty, TTYC_CNORM);
	if (tty_term_has(tty->term, TTYC_KMOUS))
		tty_puts(tty, "\033[?1000l\033[?1002l\033[?1006l\033[?1005l");

	if (tty_term_flag(tty->term, TTYC_XT)) {
		if (options_get_number(global_options, "focus-events")) {
			tty->flags |= TTY_FOCUS;
			tty_puts(tty, "\033[?1004h");
		}
	}

	tty->cx = UINT_MAX;
	tty->cy = UINT_MAX;

	tty->rlower = UINT_MAX;
	tty->rupper = UINT_MAX;

	tty->mode = MODE_CURSOR;

	tty->flags |= TTY_STARTED;

	tty_force_cursor_colour(tty, "");

	tty->mouse_drag_flag = 0;
	tty->mouse_drag_update = NULL;
	tty->mouse_drag_release = NULL;
}

void
tty_stop_tty(struct tty *tty)
{
	struct winsize	ws;

	if (!(tty->flags & TTY_STARTED))
		return;
	tty->flags &= ~TTY_STARTED;

	bufferevent_disable(tty->event, EV_READ|EV_WRITE);

	/*
	 * Be flexible about error handling and try not kill the server just
	 * because the fd is invalid. Things like ssh -t can easily leave us
	 * with a dead tty.
	 */
	if (ioctl(tty->fd, TIOCGWINSZ, &ws) == -1)
		return;
	if (tcsetattr(tty->fd, TCSANOW, &tty->tio) == -1)
		return;

	tty_raw(tty, tty_term_string2(tty->term, TTYC_CSR, 0, ws.ws_row - 1));
	if (tty_use_acs(tty))
		tty_raw(tty, tty_term_string(tty->term, TTYC_RMACS));
	tty_raw(tty, tty_term_string(tty->term, TTYC_SGR0));
	tty_raw(tty, tty_term_string(tty->term, TTYC_RMKX));
	tty_raw(tty, tty_term_string(tty->term, TTYC_CLEAR));
	if (tty_term_has(tty->term, TTYC_SS) && tty->cstyle != 0) {
		if (tty_term_has(tty->term, TTYC_SE))
			tty_raw(tty, tty_term_string(tty->term, TTYC_SE));
		else
			tty_raw(tty, tty_term_string1(tty->term, TTYC_SS, 0));
	}
	if (tty->mode & MODE_BRACKETPASTE)
		tty_raw(tty, "\033[?2004l");
	tty_raw(tty, tty_term_string(tty->term, TTYC_CR));

	tty_raw(tty, tty_term_string(tty->term, TTYC_CNORM));
	if (tty_term_has(tty->term, TTYC_KMOUS))
		tty_raw(tty, "\033[?1000l\033[?1002l\033[?1006l\033[?1005l");

	if (tty_term_flag(tty->term, TTYC_XT)) {
		if (tty->flags & TTY_FOCUS) {
			tty->flags &= ~TTY_FOCUS;
			tty_raw(tty, "\033[?1004l");
		}
	}

	tty_raw(tty, tty_term_string(tty->term, TTYC_RMCUP));

	setblocking(tty->fd, 1);
}

void
tty_close(struct tty *tty)
{
	if (event_initialized(&tty->key_timer))
		evtimer_del(&tty->key_timer);
	tty_stop_tty(tty);

	if (tty->flags & TTY_OPENED) {
		bufferevent_free(tty->event);

		tty_term_free(tty->term);
		tty_keys_free(tty);

		tty->flags &= ~TTY_OPENED;
	}

	if (tty->fd != -1) {
		close(tty->fd);
		tty->fd = -1;
	}
}

void
tty_free(struct tty *tty)
{
	tty_close(tty);

	free(tty->ccolour);
	free(tty->path);
	free(tty->termname);
}

void
tty_raw(struct tty *tty, const char *s)
{
	ssize_t	n, slen;
	u_int	i;

	slen = strlen(s);
	for (i = 0; i < 5; i++) {
		n = write(tty->fd, s, slen);
		if (n >= 0) {
			s += n;
			slen -= n;
			if (slen == 0)
				break;
		} else if (n == -1 && errno != EAGAIN)
			break;
		usleep(100);
	}
}

void
tty_putcode(struct tty *tty, enum tty_code_code code)
{
	tty_puts(tty, tty_term_string(tty->term, code));
}

void
tty_putcode1(struct tty *tty, enum tty_code_code code, int a)
{
	if (a < 0)
		return;
	tty_puts(tty, tty_term_string1(tty->term, code, a));
}

void
tty_putcode2(struct tty *tty, enum tty_code_code code, int a, int b)
{
	if (a < 0 || b < 0)
		return;
	tty_puts(tty, tty_term_string2(tty->term, code, a, b));
}

void
tty_putcode_ptr1(struct tty *tty, enum tty_code_code code, const void *a)
{
	if (a != NULL)
		tty_puts(tty, tty_term_ptr1(tty->term, code, a));
}

void
tty_putcode_ptr2(struct tty *tty, enum tty_code_code code, const void *a,
    const void *b)
{
	if (a != NULL && b != NULL)
		tty_puts(tty, tty_term_ptr2(tty->term, code, a, b));
}

void
tty_puts(struct tty *tty, const char *s)
{
	if (*s == '\0')
		return;
	bufferevent_write(tty->event, s, strlen(s));

	if (tty_log_fd != -1)
		write(tty_log_fd, s, strlen(s));
}

void
tty_putc(struct tty *tty, u_char ch)
{
	const char	*acs;
	u_int		 sx;

	if (tty->cell.attr & GRID_ATTR_CHARSET) {
		acs = tty_acs_get(tty, ch);
		if (acs != NULL)
			bufferevent_write(tty->event, acs, strlen(acs));
		else
			bufferevent_write(tty->event, &ch, 1);
	} else
		bufferevent_write(tty->event, &ch, 1);

	if (ch >= 0x20 && ch != 0x7f) {
		sx = tty->sx;
		if (tty->term->flags & TERM_EARLYWRAP)
			sx--;

		if (tty->cx >= sx) {
			tty->cx = 1;
			if (tty->cy != tty->rlower)
				tty->cy++;
		} else
			tty->cx++;
	}

	if (tty_log_fd != -1)
		write(tty_log_fd, &ch, 1);
}

void
tty_putn(struct tty *tty, const void *buf, size_t len, u_int width)
{
	bufferevent_write(tty->event, buf, len);
	if (tty_log_fd != -1)
		write(tty_log_fd, buf, len);
	tty->cx += width;
}

void
tty_set_italics(struct tty *tty)
{
	const char	*s;

	if (tty_term_has(tty->term, TTYC_SITM)) {
		s = options_get_string(global_options, "default-terminal");
		if (strcmp(s, "screen") != 0 && strncmp(s, "screen-", 7) != 0) {
			tty_putcode(tty, TTYC_SITM);
			return;
		}
	}
	tty_putcode(tty, TTYC_SMSO);
}

void
tty_set_title(struct tty *tty, const char *title)
{
	if (!tty_term_has(tty->term, TTYC_TSL) ||
	    !tty_term_has(tty->term, TTYC_FSL))
		return;

	tty_putcode(tty, TTYC_TSL);
	tty_puts(tty, title);
	tty_putcode(tty, TTYC_FSL);
}

void
tty_force_cursor_colour(struct tty *tty, const char *ccolour)
{
	if (*ccolour == '\0')
		tty_putcode(tty, TTYC_CR);
	else
		tty_putcode_ptr1(tty, TTYC_CS, ccolour);
	free(tty->ccolour);
	tty->ccolour = xstrdup(ccolour);
}

void
tty_update_mode(struct tty *tty, int mode, struct screen *s)
{
	int	changed;

	if (s != NULL && strcmp(s->ccolour, tty->ccolour))
		tty_force_cursor_colour(tty, s->ccolour);

	if (tty->flags & TTY_NOCURSOR)
		mode &= ~MODE_CURSOR;

	changed = mode ^ tty->mode;
	if (changed & MODE_BLINKING) {
		if (tty_term_has(tty->term, TTYC_CVVIS))
			tty_putcode(tty, TTYC_CVVIS);
		else
			tty_putcode(tty, TTYC_CNORM);
		changed |= MODE_CURSOR;
	}
	if (changed & MODE_CURSOR) {
		if (mode & MODE_CURSOR)
			tty_putcode(tty, TTYC_CNORM);
		else
			tty_putcode(tty, TTYC_CIVIS);
	}
	if (s != NULL && tty->cstyle != s->cstyle) {
		if (tty_term_has(tty->term, TTYC_SS)) {
			if (s->cstyle == 0 &&
			    tty_term_has(tty->term, TTYC_SE))
				tty_putcode(tty, TTYC_SE);
			else
				tty_putcode1(tty, TTYC_SS, s->cstyle);
		}
		tty->cstyle = s->cstyle;
	}
	if (changed & (ALL_MOUSE_MODES|MODE_MOUSE_UTF8)) {
		if (mode & ALL_MOUSE_MODES) {
			/*
			 * Enable the UTF-8 (1005) extension if configured to.
			 * Enable the SGR (1006) extension unconditionally, as
			 * this is safe from misinterpretation. Do it in this
			 * order, because in some terminals it's the last one
			 * that takes effect and SGR is the preferred one.
			 */
			if (mode & MODE_MOUSE_UTF8)
				tty_puts(tty, "\033[?1005h");
			else
				tty_puts(tty, "\033[?1005l");
			tty_puts(tty, "\033[?1006h");

			if (mode & MODE_MOUSE_BUTTON)
				tty_puts(tty, "\033[?1002h");
			else if (mode & MODE_MOUSE_STANDARD)
				tty_puts(tty, "\033[?1000h");
		} else {
			if (tty->mode & MODE_MOUSE_BUTTON)
				tty_puts(tty, "\033[?1002l");
			else if (tty->mode & MODE_MOUSE_STANDARD)
				tty_puts(tty, "\033[?1000l");

			tty_puts(tty, "\033[?1006l");
			if (tty->mode & MODE_MOUSE_UTF8)
				tty_puts(tty, "\033[?1005l");
		}
	}
	if (changed & MODE_KKEYPAD) {
		if (mode & MODE_KKEYPAD)
			tty_putcode(tty, TTYC_SMKX);
		else
			tty_putcode(tty, TTYC_RMKX);
	}
	if (changed & MODE_BRACKETPASTE) {
		if (mode & MODE_BRACKETPASTE)
			tty_puts(tty, "\033[?2004h");
		else
			tty_puts(tty, "\033[?2004l");
	}
	tty->mode = mode;
}

void
tty_emulate_repeat(struct tty *tty, enum tty_code_code code,
    enum tty_code_code code1, u_int n)
{
	if (tty_term_has(tty->term, code))
		tty_putcode1(tty, code, n);
	else {
		while (n-- > 0)
			tty_putcode(tty, code1);
	}
}

void
tty_repeat_space(struct tty *tty, u_int n)
{
	while (n-- > 0)
		tty_putc(tty, ' ');
}

/*
 * Is the region large enough to be worth redrawing once later rather than
 * probably several times now? Currently yes if it is more than 50% of the
 * pane.
 */
int
tty_large_region(unused struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;

	return (ctx->orlower - ctx->orupper >= screen_size_y(wp->screen) / 2);
}

/*
 * Return if BCE is needed but the terminal doesn't have it - it'll need to be
 * emulated.
 */
int
tty_fake_bce(const struct tty *tty, const struct window_pane *wp)
{
	struct grid_cell	gc;

	memcpy(&gc, &grid_default_cell, sizeof gc);
	tty_default_colours(&gc, wp);

	if (gc.bg == 8 && !(gc.flags & GRID_FLAG_BG256))
		return (0);
	return (!tty_term_flag(tty->term, TTYC_BCE));
}

/*
 * Redraw scroll region using data from screen (already updated). Used when
 * CSR not supported, or window is a pane that doesn't take up the full
 * width of the terminal.
 */
void
tty_redraw_region(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int		 	 i;

	/*
	 * If region is large, schedule a window redraw. In most cases this is
	 * likely to be followed by some more scrolling.
	 */
	if (tty_large_region(tty, ctx)) {
		wp->flags |= PANE_REDRAW;
		return;
	}

	if (ctx->ocy < ctx->orupper || ctx->ocy > ctx->orlower) {
		for (i = ctx->ocy; i < screen_size_y(s); i++)
			tty_draw_pane(tty, wp, i, ctx->xoff, ctx->yoff);
	} else {
		for (i = ctx->orupper; i <= ctx->orlower; i++)
			tty_draw_pane(tty, wp, i, ctx->xoff, ctx->yoff);
	}
}

void
tty_draw_pane(struct tty *tty, const struct window_pane *wp, u_int py, u_int ox,
    u_int oy)
{
	tty_draw_line(tty, wp, wp->screen, py, ox, oy);
}

void
tty_draw_line(struct tty *tty, const struct window_pane *wp,
    struct screen *s, u_int py, u_int ox, u_int oy)
{
	struct grid_cell	 gc;
	struct grid_line	*gl;
	u_int			 i, sx;
	int			 flags;

	flags = tty->flags & TTY_NOCURSOR;
	tty->flags |= TTY_NOCURSOR;
	tty_update_mode(tty, tty->mode, s);

	sx = screen_size_x(s);
	if (sx > s->grid->linedata[s->grid->hsize + py].cellsize)
		sx = s->grid->linedata[s->grid->hsize + py].cellsize;
	if (sx > tty->sx)
		sx = tty->sx;

	/*
	 * Don't move the cursor to the start position if it will wrap there
	 * itself.
	 */
	gl = NULL;
	if (py != 0)
		gl = &s->grid->linedata[s->grid->hsize + py - 1];
	if (oy + py == 0 || gl == NULL || !(gl->flags & GRID_LINE_WRAPPED) ||
	    tty->cx < tty->sx || ox != 0 ||
	    (oy + py != tty->cy + 1 && tty->cy != s->rlower + oy))
		tty_cursor(tty, ox, oy + py);

	for (i = 0; i < sx; i++) {
		grid_view_get_cell(s->grid, i, py, &gc);
		if (screen_check_selection(s, i, py)) {
			gc.flags &= ~(GRID_FLAG_FG256|GRID_FLAG_BG256);
			gc.flags |= s->sel.cell.flags &
			    (GRID_FLAG_FG256|GRID_FLAG_BG256);
		}
		tty_cell(tty, &gc, wp);
	}

	if (sx < tty->sx) {
		tty_attributes(tty, &grid_default_cell, wp);

		tty_cursor(tty, ox + sx, oy + py);
		if (sx != screen_size_x(s) &&
		    ox + screen_size_x(s) >= tty->sx &&
		    tty_term_has(tty->term, TTYC_EL) &&
		    !tty_fake_bce(tty, wp))
			tty_putcode(tty, TTYC_EL);
		else
			tty_repeat_space(tty, screen_size_x(s) - sx);
	}

	tty->flags = (tty->flags & ~TTY_NOCURSOR) | flags;
	tty_update_mode(tty, tty->mode, s);
}

int
tty_client_ready(struct client *c, struct window_pane *wp)
{
	if (c->session == NULL || c->tty.term == NULL)
		return (0);
	if (c->flags & CLIENT_SUSPENDED)
		return (0);
	if (c->tty.flags & TTY_FREEZE)
		return (0);
	if (c->session->curw->window != wp->window)
		return (0);
	return (1);
}

void
tty_write(void (*cmdfn)(struct tty *, const struct tty_ctx *),
    struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct client		*c;

	/* wp can be NULL if updating the screen but not the terminal. */
	if (wp == NULL)
		return;

	if (wp->window->flags & WINDOW_REDRAW || wp->flags & PANE_REDRAW)
		return;
	if (!window_pane_visible(wp) || wp->flags & PANE_DROP)
		return;

	TAILQ_FOREACH(c, &clients, entry) {
		if (!tty_client_ready(c, wp))
			continue;

		ctx->xoff = wp->xoff;
		ctx->yoff = wp->yoff;
		if (status_at_line(c) == 0)
			ctx->yoff++;

		cmdfn(&c->tty, ctx);
	}
}

void
tty_cmd_insertcharacter(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;

	if (!tty_pane_full_width(tty, ctx)) {
		tty_draw_pane(tty, wp, ctx->ocy, ctx->xoff, ctx->yoff);
		return;
	}

	tty_attributes(tty, &grid_default_cell, wp);

	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	if (!tty_fake_bce(tty, wp) && (tty_term_has(tty->term, TTYC_ICH) ||
	    tty_term_has(tty->term, TTYC_ICH1)))
		tty_emulate_repeat(tty, TTYC_ICH, TTYC_ICH1, ctx->num);
	else
		tty_draw_pane(tty, wp, ctx->ocy, ctx->xoff, ctx->yoff);
}

void
tty_cmd_deletecharacter(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;

	if (!tty_pane_full_width(tty, ctx) || tty_fake_bce(tty, wp) ||
	    (!tty_term_has(tty->term, TTYC_DCH) &&
	    !tty_term_has(tty->term, TTYC_DCH1))) {
		tty_draw_pane(tty, wp, ctx->ocy, ctx->xoff, ctx->yoff);
		return;
	}

	tty_attributes(tty, &grid_default_cell, wp);

	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	if (tty_term_has(tty->term, TTYC_DCH) ||
	    tty_term_has(tty->term, TTYC_DCH1))
		tty_emulate_repeat(tty, TTYC_DCH, TTYC_DCH1, ctx->num);
}

void
tty_cmd_clearcharacter(struct tty *tty, const struct tty_ctx *ctx)
{
	u_int	i;

	tty_attributes(tty, &grid_default_cell, ctx->wp);

	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	if (tty_term_has(tty->term, TTYC_ECH) && !tty_fake_bce(tty, ctx->wp))
		tty_putcode1(tty, TTYC_ECH, ctx->num);
	else {
		for (i = 0; i < ctx->num; i++)
			tty_putc(tty, ' ');
	}
}

void
tty_cmd_insertline(struct tty *tty, const struct tty_ctx *ctx)
{
	if (!tty_pane_full_width(tty, ctx) || tty_fake_bce(tty, ctx->wp) ||
	    !tty_term_has(tty->term, TTYC_CSR) ||
	    !tty_term_has(tty->term, TTYC_IL1)) {
		tty_redraw_region(tty, ctx);
		return;
	}

	tty_attributes(tty, &grid_default_cell, ctx->wp);

	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	tty_emulate_repeat(tty, TTYC_IL, TTYC_IL1, ctx->num);
}

void
tty_cmd_deleteline(struct tty *tty, const struct tty_ctx *ctx)
{
	if (!tty_pane_full_width(tty, ctx) || tty_fake_bce(tty, ctx->wp) ||
	    !tty_term_has(tty->term, TTYC_CSR) ||
	    !tty_term_has(tty->term, TTYC_DL1)) {
		tty_redraw_region(tty, ctx);
		return;
	}

	tty_attributes(tty, &grid_default_cell, ctx->wp);

	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	tty_emulate_repeat(tty, TTYC_DL, TTYC_DL1, ctx->num);
}

void
tty_cmd_clearline(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_cursor_pane(tty, ctx, 0, ctx->ocy);

	if (tty_pane_full_width(tty, ctx) && !tty_fake_bce(tty, wp) &&
	    tty_term_has(tty->term, TTYC_EL))
		tty_putcode(tty, TTYC_EL);
	else
		tty_repeat_space(tty, screen_size_x(s));
}

void
tty_cmd_clearendofline(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	if (tty_pane_full_width(tty, ctx) &&
	    tty_term_has(tty->term, TTYC_EL) && !tty_fake_bce(tty, wp))
		tty_putcode(tty, TTYC_EL);
	else
		tty_repeat_space(tty, screen_size_x(s) - ctx->ocx);
}

void
tty_cmd_clearstartofline(struct tty *tty, const struct tty_ctx *ctx)
{
	tty_attributes(tty, &grid_default_cell, ctx->wp);

	if (ctx->xoff == 0 && tty_term_has(tty->term, TTYC_EL1) &&
	    !tty_fake_bce(tty, ctx->wp)) {
		tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);
		tty_putcode(tty, TTYC_EL1);
	} else {
		tty_cursor_pane(tty, ctx, 0, ctx->ocy);
		tty_repeat_space(tty, ctx->ocx + 1);
	}
}

void
tty_cmd_reverseindex(struct tty *tty, const struct tty_ctx *ctx)
{
	if (ctx->ocy != ctx->orupper)
		return;

	if (!tty_pane_full_width(tty, ctx) || tty_fake_bce(tty, ctx->wp) ||
	    !tty_term_has(tty->term, TTYC_CSR) ||
	    !tty_term_has(tty->term, TTYC_RI)) {
		tty_redraw_region(tty, ctx);
		return;
	}

	tty_attributes(tty, &grid_default_cell, ctx->wp);

	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->orupper);

	tty_putcode(tty, TTYC_RI);
}

void
tty_cmd_linefeed(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;

	if (ctx->ocy != ctx->orlower)
		return;

	if (!tty_pane_full_width(tty, ctx) || tty_fake_bce(tty, wp) ||
	    !tty_term_has(tty->term, TTYC_CSR)) {
		if (tty_large_region(tty, ctx))
			wp->flags |= PANE_REDRAW;
		else
			tty_redraw_region(tty, ctx);
		return;
	}

	/*
	 * If this line wrapped naturally (ctx->num is nonzero), don't do
	 * anything - the cursor can just be moved to the last cell and wrap
	 * naturally.
	 */
	if (ctx->num && !(tty->term->flags & TERM_EARLYWRAP))
		return;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);
	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	tty_putc(tty, '\n');
}

void
tty_cmd_clearendofscreen(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int		 	 i, j;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_region_pane(tty, ctx, 0, screen_size_y(s) - 1);
	tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	if (tty_pane_full_width(tty, ctx) &&
	    tty_term_has(tty->term, TTYC_EL) && !tty_fake_bce(tty, wp)) {
		tty_putcode(tty, TTYC_EL);
		if (ctx->ocy != screen_size_y(s) - 1) {
			tty_cursor_pane(tty, ctx, 0, ctx->ocy + 1);
			for (i = ctx->ocy + 1; i < screen_size_y(s); i++) {
				tty_putcode(tty, TTYC_EL);
				if (i == screen_size_y(s) - 1)
					continue;
				tty_emulate_repeat(tty, TTYC_CUD, TTYC_CUD1, 1);
				tty->cy++;
			}
		}
	} else {
		tty_repeat_space(tty, screen_size_x(s) - ctx->ocx);
		for (j = ctx->ocy + 1; j < screen_size_y(s); j++) {
			tty_cursor_pane(tty, ctx, 0, j);
			tty_repeat_space(tty, screen_size_x(s));
		}
	}
}

void
tty_cmd_clearstartofscreen(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int		 	 i, j;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_region_pane(tty, ctx, 0, screen_size_y(s) - 1);
	tty_cursor_pane(tty, ctx, 0, 0);

	if (tty_pane_full_width(tty, ctx) &&
	    tty_term_has(tty->term, TTYC_EL) && !tty_fake_bce(tty, wp)) {
		for (i = 0; i < ctx->ocy; i++) {
			tty_putcode(tty, TTYC_EL);
			tty_emulate_repeat(tty, TTYC_CUD, TTYC_CUD1, 1);
			tty->cy++;
		}
	} else {
		for (j = 0; j < ctx->ocy; j++) {
			tty_cursor_pane(tty, ctx, 0, j);
			tty_repeat_space(tty, screen_size_x(s));
		}
	}
	tty_repeat_space(tty, ctx->ocx + 1);
}

void
tty_cmd_clearscreen(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int		 	 i, j;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_region_pane(tty, ctx, 0, screen_size_y(s) - 1);
	tty_cursor_pane(tty, ctx, 0, 0);

	if (tty_pane_full_width(tty, ctx) &&
	    tty_term_has(tty->term, TTYC_EL) && !tty_fake_bce(tty, wp)) {
		for (i = 0; i < screen_size_y(s); i++) {
			tty_putcode(tty, TTYC_EL);
			if (i != screen_size_y(s) - 1) {
				tty_emulate_repeat(tty, TTYC_CUD, TTYC_CUD1, 1);
				tty->cy++;
			}
		}
	} else {
		for (j = 0; j < screen_size_y(s); j++) {
			tty_cursor_pane(tty, ctx, 0, j);
			tty_repeat_space(tty, screen_size_x(s));
		}
	}
}

void
tty_cmd_alignmenttest(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int			 i, j;

	tty_attributes(tty, &grid_default_cell, wp);

	tty_region_pane(tty, ctx, 0, screen_size_y(s) - 1);

	for (j = 0; j < screen_size_y(s); j++) {
		tty_cursor_pane(tty, ctx, 0, j);
		for (i = 0; i < screen_size_x(s); i++)
			tty_putc(tty, 'E');
	}
}

void
tty_cmd_cell(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;
	struct screen		*s = wp->screen;
	u_int			 cx;
	u_int			 width;

	tty_region_pane(tty, ctx, ctx->orupper, ctx->orlower);

	/* Is the cursor in the very last position? */
	width = ctx->cell->data.width;
	if (ctx->ocx > wp->sx - width) {
		if (ctx->xoff != 0 || wp->sx != tty->sx) {
			/*
			 * The pane doesn't fill the entire line, the linefeed
			 * will already have happened, so just move the cursor.
			 */
			if (ctx->ocy != wp->yoff + wp->screen->rlower)
				tty_cursor_pane(tty, ctx, 0, ctx->ocy + 1);
			else
				tty_cursor_pane(tty, ctx, 0, ctx->ocy);
		} else if (tty->cx < tty->sx) {
			/*
			 * The cursor isn't in the last position already, so
			 * move as far left as possible and redraw the last
			 * cell to move into the last position.
			 */
			cx = screen_size_x(s) - ctx->last_cell.data.width;
			tty_cursor_pane(tty, ctx, cx, ctx->ocy);
			tty_cell(tty, &ctx->last_cell, wp);
		}
	} else
		tty_cursor_pane(tty, ctx, ctx->ocx, ctx->ocy);

	tty_cell(tty, ctx->cell, wp);
}

void
tty_cmd_utf8character(struct tty *tty, const struct tty_ctx *ctx)
{
	struct window_pane	*wp = ctx->wp;

	/*
	 * Cannot rely on not being a partial character, so just redraw the
	 * whole line.
	 */
	tty_draw_pane(tty, wp, ctx->ocy, ctx->xoff, ctx->yoff);
}

void
tty_cmd_setselection(struct tty *tty, const struct tty_ctx *ctx)
{
	char	*buf;
	size_t	 off;

	if (!tty_term_has(tty->term, TTYC_MS))
		return;

	off = 4 * ((ctx->num + 2) / 3) + 1; /* storage for base64 */
	buf = xmalloc(off);

	b64_ntop(ctx->ptr, ctx->num, buf, off);
	tty_putcode_ptr2(tty, TTYC_MS, "", buf);

	free(buf);
}

void
tty_cmd_rawstring(struct tty *tty, const struct tty_ctx *ctx)
{
	u_int	 i;
	u_char	*str = ctx->ptr;

	for (i = 0; i < ctx->num; i++)
		tty_putc(tty, str[i]);

	tty->cx = tty->cy = UINT_MAX;
	tty->rupper = tty->rlower = UINT_MAX;

	tty_attributes(tty, &grid_default_cell, ctx->wp);
	tty_cursor(tty, 0, 0);
}

void
tty_cell(struct tty *tty, const struct grid_cell *gc,
    const struct window_pane *wp)
{
	u_int	i;

	/* Skip last character if terminal is stupid. */
	if (tty->term->flags & TERM_EARLYWRAP &&
	    tty->cy == tty->sy - 1 && tty->cx == tty->sx - 1)
		return;

	/* If this is a padding character, do nothing. */
	if (gc->flags & GRID_FLAG_PADDING)
		return;

	/* Set the attributes. */
	tty_attributes(tty, gc, wp);

	/* Get the cell and if ASCII write with putc to do ACS translation. */
	if (gc->data.size == 1) {
		if (*gc->data.data < 0x20 || *gc->data.data == 0x7f)
			return;
		tty_putc(tty, *gc->data.data);
		return;
	}

	/* If not UTF-8, write _. */
	if (!(tty->flags & TTY_UTF8)) {
		for (i = 0; i < gc->data.width; i++)
			tty_putc(tty, '_');
		return;
	}

	/* Write the data. */
	tty_putn(tty, gc->data.data, gc->data.size, gc->data.width);
}

void
tty_reset(struct tty *tty)
{
	struct grid_cell	*gc = &tty->cell;

	if (memcmp(gc, &grid_default_cell, sizeof *gc) == 0)
		return;

	if ((gc->attr & GRID_ATTR_CHARSET) && tty_use_acs(tty))
		tty_putcode(tty, TTYC_RMACS);
	tty_putcode(tty, TTYC_SGR0);
	memcpy(gc, &grid_default_cell, sizeof *gc);
}

/* Set region inside pane. */
void
tty_region_pane(
    struct tty *tty, const struct tty_ctx *ctx, u_int rupper, u_int rlower)
{
	tty_region(tty, ctx->yoff + rupper, ctx->yoff + rlower);
}

/* Set region at absolute position. */
void
tty_region(struct tty *tty, u_int rupper, u_int rlower)
{
	if (tty->rlower == rlower && tty->rupper == rupper)
		return;
	if (!tty_term_has(tty->term, TTYC_CSR))
		return;

	tty->rupper = rupper;
	tty->rlower = rlower;

	/*
	 * Some terminals (such as PuTTY) do not correctly reset the cursor to
	 * 0,0 if it is beyond the last column (they do not reset their wrap
	 * flag so further output causes a line feed). As a workaround, do an
	 * explicit move to 0 first.
	 */
	if (tty->cx >= tty->sx)
		tty_cursor(tty, 0, tty->cy);

	tty_putcode2(tty, TTYC_CSR, tty->rupper, tty->rlower);
	tty_cursor(tty, 0, 0);
}

/* Move cursor inside pane. */
void
tty_cursor_pane(struct tty *tty, const struct tty_ctx *ctx, u_int cx, u_int cy)
{
	tty_cursor(tty, ctx->xoff + cx, ctx->yoff + cy);
}

/* Move cursor to absolute position. */
void
tty_cursor(struct tty *tty, u_int cx, u_int cy)
{
	struct tty_term	*term = tty->term;
	u_int		 thisx, thisy;
	int		 change;

	if (cx > tty->sx - 1)
		cx = tty->sx - 1;

	thisx = tty->cx;
	thisy = tty->cy;

	/* No change. */
	if (cx == thisx && cy == thisy)
		return;

	/* Very end of the line, just use absolute movement. */
	if (thisx > tty->sx - 1)
		goto absolute;

	/* Move to home position (0, 0). */
	if (cx == 0 && cy == 0 && tty_term_has(term, TTYC_HOME)) {
		tty_putcode(tty, TTYC_HOME);
		goto out;
	}

	/* Zero on the next line. */
	if (cx == 0 && cy == thisy + 1 && thisy != tty->rlower) {
		tty_putc(tty, '\r');
		tty_putc(tty, '\n');
		goto out;
	}

	/* Moving column or row. */
	if (cy == thisy) {
		/*
		 * Moving column only, row staying the same.
		 */

		/* To left edge. */
		if (cx == 0)	{
			tty_putc(tty, '\r');
			goto out;
		}

		/* One to the left. */
		if (cx == thisx - 1 && tty_term_has(term, TTYC_CUB1)) {
			tty_putcode(tty, TTYC_CUB1);
			goto out;
		}

		/* One to the right. */
		if (cx == thisx + 1 && tty_term_has(term, TTYC_CUF1)) {
			tty_putcode(tty, TTYC_CUF1);
			goto out;
		}

		/* Calculate difference. */
		change = thisx - cx;	/* +ve left, -ve right */

		/*
		 * Use HPA if change is larger than absolute, otherwise move
		 * the cursor with CUB/CUF.
		 */
		if ((u_int) abs(change) > cx && tty_term_has(term, TTYC_HPA)) {
			tty_putcode1(tty, TTYC_HPA, cx);
			goto out;
		} else if (change > 0 && tty_term_has(term, TTYC_CUB)) {
			tty_putcode1(tty, TTYC_CUB, change);
			goto out;
		} else if (change < 0 && tty_term_has(term, TTYC_CUF)) {
			tty_putcode1(tty, TTYC_CUF, -change);
			goto out;
		}
	} else if (cx == thisx) {
		/*
		 * Moving row only, column staying the same.
		 */

		/* One above. */
		if (thisy != tty->rupper &&
		    cy == thisy - 1 && tty_term_has(term, TTYC_CUU1)) {
			tty_putcode(tty, TTYC_CUU1);
			goto out;
		}

		/* One below. */
		if (thisy != tty->rlower &&
		    cy == thisy + 1 && tty_term_has(term, TTYC_CUD1)) {
			tty_putcode(tty, TTYC_CUD1);
			goto out;
		}

		/* Calculate difference. */
		change = thisy - cy;	/* +ve up, -ve down */

		/*
		 * Try to use VPA if change is larger than absolute or if this
		 * change would cross the scroll region, otherwise use CUU/CUD.
		 */
		if ((u_int) abs(change) > cy ||
		    (change < 0 && cy - change > tty->rlower) ||
		    (change > 0 && cy - change < tty->rupper)) {
			    if (tty_term_has(term, TTYC_VPA)) {
				    tty_putcode1(tty, TTYC_VPA, cy);
				    goto out;
			    }
		} else if (change > 0 && tty_term_has(term, TTYC_CUU)) {
			tty_putcode1(tty, TTYC_CUU, change);
			goto out;
		} else if (change < 0 && tty_term_has(term, TTYC_CUD)) {
			tty_putcode1(tty, TTYC_CUD, -change);
			goto out;
		}
	}

absolute:
	/* Absolute movement. */
	tty_putcode2(tty, TTYC_CUP, cy, cx);

out:
	tty->cx = cx;
	tty->cy = cy;
}

void
tty_attributes(struct tty *tty, const struct grid_cell *gc,
    const struct window_pane *wp)
{
	struct grid_cell	*tc = &tty->cell, gc2;
	u_char			 changed;

	memcpy(&gc2, gc, sizeof gc2);
	tty_default_colours(&gc2, wp);

	/*
	 * If no setab, try to use the reverse attribute as a best-effort for a
	 * non-default background. This is a bit of a hack but it doesn't do
	 * any serious harm and makes a couple of applications happier.
	 */
	if (!tty_term_has(tty->term, TTYC_SETAB)) {
		if (gc2.attr & GRID_ATTR_REVERSE) {
			if (gc2.fg != 7 && gc2.fg != 8)
				gc2.attr &= ~GRID_ATTR_REVERSE;
		} else {
			if (gc2.bg != 0 && gc2.bg != 8)
				gc2.attr |= GRID_ATTR_REVERSE;
		}
	}

	/* Fix up the colours if necessary. */
	tty_check_fg(tty, &gc2);
	tty_check_bg(tty, &gc2);

	/* If any bits are being cleared, reset everything. */
	if (tc->attr & ~gc2.attr)
		tty_reset(tty);

	/*
	 * Set the colours. This may call tty_reset() (so it comes next) and
	 * may add to (NOT remove) the desired attributes by changing new_attr.
	 */
	tty_colours(tty, &gc2);

	/* Filter out attribute bits already set. */
	changed = gc2.attr & ~tc->attr;
	tc->attr = gc2.attr;

	/* Set the attributes. */
	if (changed & GRID_ATTR_BRIGHT)
		tty_putcode(tty, TTYC_BOLD);
	if (changed & GRID_ATTR_DIM)
		tty_putcode(tty, TTYC_DIM);
	if (changed & GRID_ATTR_ITALICS)
		tty_set_italics(tty);
	if (changed & GRID_ATTR_UNDERSCORE)
		tty_putcode(tty, TTYC_SMUL);
	if (changed & GRID_ATTR_BLINK)
		tty_putcode(tty, TTYC_BLINK);
	if (changed & GRID_ATTR_REVERSE) {
		if (tty_term_has(tty->term, TTYC_REV))
			tty_putcode(tty, TTYC_REV);
		else if (tty_term_has(tty->term, TTYC_SMSO))
			tty_putcode(tty, TTYC_SMSO);
	}
	if (changed & GRID_ATTR_HIDDEN)
		tty_putcode(tty, TTYC_INVIS);
	if ((changed & GRID_ATTR_CHARSET) && tty_use_acs(tty))
		tty_putcode(tty, TTYC_SMACS);
}

void
tty_colours(struct tty *tty, const struct grid_cell *gc)
{
	struct grid_cell	*tc = &tty->cell;
	u_char			 fg = gc->fg, bg = gc->bg, flags = gc->flags;
	int			 have_ax, fg_default, bg_default;

	/* No changes? Nothing is necessary. */
	if (fg == tc->fg && bg == tc->bg &&
	    ((flags ^ tc->flags) & (GRID_FLAG_FG256|GRID_FLAG_BG256)) == 0)
		return;

	/*
	 * Is either the default colour? This is handled specially because the
	 * best solution might be to reset both colours to default, in which
	 * case if only one is default need to fall onward to set the other
	 * colour.
	 */
	fg_default = (fg == 8 && !(flags & GRID_FLAG_FG256));
	bg_default = (bg == 8 && !(flags & GRID_FLAG_BG256));
	if (fg_default || bg_default) {
		/*
		 * If don't have AX but do have op, send sgr0 (op can't
		 * actually be used because it is sometimes the same as sgr0
		 * and sometimes isn't). This resets both colours to default.
		 *
		 * Otherwise, try to set the default colour only as needed.
		 */
		have_ax = tty_term_flag(tty->term, TTYC_AX);
		if (!have_ax && tty_term_has(tty->term, TTYC_OP))
			tty_reset(tty);
		else {
			if (fg_default &&
			    (tc->fg != 8 || tc->flags & GRID_FLAG_FG256)) {
				if (have_ax)
					tty_puts(tty, "\033[39m");
				else if (tc->fg != 7 ||
				    tc->flags & GRID_FLAG_FG256)
					tty_putcode1(tty, TTYC_SETAF, 7);
				tc->fg = 8;
				tc->flags &= ~GRID_FLAG_FG256;
			}
			if (bg_default &&
			    (tc->bg != 8 || tc->flags & GRID_FLAG_BG256)) {
				if (have_ax)
					tty_puts(tty, "\033[49m");
				else if (tc->bg != 0 ||
				    tc->flags & GRID_FLAG_BG256)
					tty_putcode1(tty, TTYC_SETAB, 0);
				tc->bg = 8;
				tc->flags &= ~GRID_FLAG_BG256;
			}
		}
	}

	/* Set the foreground colour. */
	if (!fg_default && (fg != tc->fg ||
	    ((flags & GRID_FLAG_FG256) != (tc->flags & GRID_FLAG_FG256))))
		tty_colours_fg(tty, gc);

	/*
	 * Set the background colour. This must come after the foreground as
	 * tty_colour_fg() can call tty_reset().
	 */
	if (!bg_default && (bg != tc->bg ||
	    ((flags & GRID_FLAG_BG256) != (tc->flags & GRID_FLAG_BG256))))
		tty_colours_bg(tty, gc);
}

void
tty_check_fg(struct tty *tty, struct grid_cell *gc)
{
	u_int	colours;

	colours = tty_term_number(tty->term, TTYC_COLORS);

	/* Is this a 256-colour colour? */
	if (gc->flags & GRID_FLAG_FG256) {
		/* And not a 256 colour mode? */
		if (!(tty->term->flags & TERM_256COLOURS) &&
		    !(tty->term_flags & TERM_256COLOURS)) {
			gc->fg = colour_256to16(gc->fg);
			if (gc->fg & 8) {
				gc->fg &= 7;
				if (colours >= 16)
					gc->fg += 90;
				else
					gc->attr |= GRID_ATTR_BRIGHT;
			} else
				gc->attr &= ~GRID_ATTR_BRIGHT;
			gc->flags &= ~GRID_FLAG_FG256;
		}
		return;
	}

	/* Is this an aixterm colour? */
	if (gc->fg >= 90 && gc->fg <= 97 && colours < 16) {
		gc->fg -= 90;
		gc->attr |= GRID_ATTR_BRIGHT;
	}
}

void
tty_check_bg(struct tty *tty, struct grid_cell *gc)
{
	u_int	colours;

	colours = tty_term_number(tty->term, TTYC_COLORS);

	/* Is this a 256-colour colour? */
	if (gc->flags & GRID_FLAG_BG256) {
		/*
		 * And not a 256 colour mode? Translate to 16-colour
		 * palette. Bold background doesn't exist portably, so just
		 * discard the bold bit if set.
		 */
		if (!(tty->term->flags & TERM_256COLOURS) &&
		    !(tty->term_flags & TERM_256COLOURS)) {
			gc->bg = colour_256to16(gc->bg);
			if (gc->bg & 8) {
				gc->bg &= 7;
				if (colours >= 16)
					gc->fg += 90;
			}
			gc->flags &= ~GRID_FLAG_BG256;
		}
		return;
	}

	/* Is this an aixterm colour? */
	if (gc->bg >= 90 && gc->bg <= 97 && colours < 16)
		gc->bg -= 90;
}

void
tty_colours_fg(struct tty *tty, const struct grid_cell *gc)
{
	struct grid_cell	*tc = &tty->cell;
	u_char			 fg = gc->fg;
	char			 s[32];

	/* Is this a 256-colour colour? */
	if (gc->flags & GRID_FLAG_FG256) {
		/* Try as 256 colours. */
		if (tty_try_256(tty, fg, "38") == 0)
			goto save_fg;
		/* Else already handled by tty_check_fg. */
		return;
	}

	/* Is this an aixterm bright colour? */
	if (fg >= 90 && fg <= 97) {
		xsnprintf(s, sizeof s, "\033[%dm", fg);
		tty_puts(tty, s);
		goto save_fg;
	}

	/* Otherwise set the foreground colour. */
	tty_putcode1(tty, TTYC_SETAF, fg);

save_fg:
	/* Save the new values in the terminal current cell. */
	tc->fg = fg;
	tc->flags &= ~GRID_FLAG_FG256;
	tc->flags |= gc->flags & GRID_FLAG_FG256;
}

void
tty_colours_bg(struct tty *tty, const struct grid_cell *gc)
{
	struct grid_cell	*tc = &tty->cell;
	u_char			 bg = gc->bg;
	char			 s[32];

	/* Is this a 256-colour colour? */
	if (gc->flags & GRID_FLAG_BG256) {
		/* Try as 256 colours. */
		if (tty_try_256(tty, bg, "48") == 0)
			goto save_bg;
		/* Else already handled by tty_check_bg. */
		return;
	}

	/* Is this an aixterm bright colour? */
	if (bg >= 90 && bg <= 97) {
		xsnprintf(s, sizeof s, "\033[%dm", bg + 10);
		tty_puts(tty, s);
		goto save_bg;
	}

	/* Otherwise set the background colour. */
	tty_putcode1(tty, TTYC_SETAB, bg);

save_bg:
	/* Save the new values in the terminal current cell. */
	tc->bg = bg;
	tc->flags &= ~GRID_FLAG_BG256;
	tc->flags |= gc->flags & GRID_FLAG_BG256;
}

int
tty_try_256(struct tty *tty, u_char colour, const char *type)
{
	char	s[32];

	/*
	 * If the user has specified -2 to the client, setaf and setab may not
	 * work (or they may not want to use them), so send the usual sequence.
	 */
	if (tty->term_flags & TERM_256COLOURS)
		goto fallback;

	/*
	 * If the terminfo entry has 256 colours and setaf and setab exist,
	 * assume that they work correctly.
	 */
	if (tty->term->flags & TERM_256COLOURS) {
		if (*type == '3') {
			if (!tty_term_has(tty->term, TTYC_SETAF))
				goto fallback;
			tty_putcode1(tty, TTYC_SETAF, colour);
		} else {
			if (!tty_term_has(tty->term, TTYC_SETAB))
				goto fallback;
			tty_putcode1(tty, TTYC_SETAB, colour);
		}
		return (0);
	}

	return (-1);

fallback:
	xsnprintf(s, sizeof s, "\033[%s;5;%hhum", type, colour);
	tty_puts(tty, s);
	return (0);
}

void
tty_default_colours(struct grid_cell *gc, const struct window_pane *wp)
{
	const struct grid_cell        *agc, *pgc, *wgc;

	if (wp == NULL)
		return;

	pgc = &wp->colgc;
	agc = options_get_style(wp->window->options, "window-active-style");
	wgc = options_get_style(wp->window->options, "window-style");

	if (gc->fg == 8 && !(gc->flags & GRID_FLAG_FG256)) {
		if (pgc->fg != 8 || (pgc->flags & GRID_FLAG_FG256)) {
			gc->fg = pgc->fg;
			gc->flags |= (pgc->flags & GRID_FLAG_FG256);
		} else if (wp == wp->window->active &&
		    (agc->fg != 8 || (agc->flags & GRID_FLAG_FG256))) {
			gc->fg = agc->fg;
			gc->flags |= (agc->flags & GRID_FLAG_FG256);
		} else {
			gc->fg = wgc->fg;
			gc->flags |= (wgc->flags & GRID_FLAG_FG256);
		}
	}

	if (gc->bg == 8 && !(gc->flags & GRID_FLAG_BG256)) {
		if (pgc->bg != 8 || (pgc->flags & GRID_FLAG_BG256)) {
			gc->bg = pgc->bg;
			gc->flags |= (pgc->flags & GRID_FLAG_BG256);
		} else if (wp == wp->window->active &&
		    (agc->bg != 8 || (agc->flags & GRID_FLAG_BG256))) {
			gc->bg = agc->bg;
			gc->flags |= (agc->flags & GRID_FLAG_BG256);
		} else {
			gc->bg = wgc->bg;
			gc->flags |= (wgc->flags & GRID_FLAG_BG256);
		}
	}
}