Return to screen-write.c CVS log

Up to [local] / src / usr.bin / tmux

Don't update cells in each block of data read from a pane immediately,
instead track them as change (dirty) and update them once at the end,
saves much time if repeatedly writing the same cell. Also fix comparison
of cells being equal in a few places (memcmp is not enough).

/* $OpenBSD: screen-write.c,v 1.92 2016/07/15 00:49:08 nicm Exp $ */

/*
 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * 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 <stdlib.h>
#include <string.h>

#include "tmux.h"

static void	screen_write_initctx(struct screen_write_ctx *,
		    struct tty_ctx *);
static void	screen_write_save_last(struct screen_write_ctx *,
		    struct tty_ctx *);
static void	screen_write_flush(struct screen_write_ctx *);

static int	screen_write_overwrite(struct screen_write_ctx *,
		    struct grid_cell *, u_int);
static int	screen_write_combine(struct screen_write_ctx *,
		    const struct utf8_data *);

static const struct grid_cell screen_write_pad_cell = {
	GRID_FLAG_PADDING, 0, 8, 8, { { 0 }, 0, 0, 0 }
};

#define screen_dirty_bit(s, x, y) (((y) * screen_size_x(s)) + (x))
#define screen_dirty_clear(s, sx, sy, ex, ey)			\
	do {							\
		if (s->dirty != NULL) {				\
			bit_nclear(s->dirty,			\
			    screen_dirty_bit(s, sx, sy),	\
			    screen_dirty_bit(s, ex, ey));	\
		}						\
	} while (0)

/* Initialize writing with a window. */
void
screen_write_start(struct screen_write_ctx *ctx, struct window_pane *wp,
    struct screen *s)
{
	u_int		 size;
	char		 tmp[16];
	const char	*cp = tmp;

	ctx->wp = wp;
	if (wp != NULL && s == NULL)
		ctx->s = wp->screen;
	else
		ctx->s = s;

	size = screen_size_x(ctx->s) * screen_size_y(ctx->s);
	if (ctx->s->dirtysize != size) {
		free(ctx->s->dirty);
		ctx->s->dirty = NULL;
		ctx->s->dirtysize = size;
	}
	ctx->dirty = 0;

	ctx->cells = ctx->written = ctx->skipped = 0;

	if (wp == NULL)
		cp = "no pane";
	else
		snprintf(tmp, sizeof tmp, "pane %%%u", wp->id);
	log_debug("%s: size %ux%u, %s", __func__, screen_size_x(ctx->s),
	    screen_size_y(ctx->s), cp);
}

/* Finish writing. */
void
screen_write_stop(struct screen_write_ctx *ctx)
{
	screen_write_flush(ctx);

	log_debug("%s: %u of %u written (dirty %u, skipped %u)", __func__,
	    ctx->written, ctx->cells, ctx->cells - ctx->written, ctx->skipped);
}

/* Flush outstanding cell writes. */
static void
screen_write_flush(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;
	u_int		 x, y, offset, cx, cy, dirty;
	struct grid_cell gc;

	if (ctx->dirty == 0)
		return;
	dirty = 0;

	cx = s->cx;
	cy = s->cy;

	offset = 0;
	for (y = 0; y < screen_size_y(s); y++) {
		for (x = 0; x < screen_size_x(s); x++) {
			offset++;
			if (!bit_test(s->dirty, offset - 1))
				continue;
			bit_clear(s->dirty, offset - 1);

			screen_write_cursormove(ctx, x, y);
			grid_view_get_cell(s->grid, x, y, &gc);

			screen_write_initctx(ctx, &ttyctx);
			ttyctx.cell = &gc;
			tty_write(tty_cmd_cell, &ttyctx);
			ctx->written++;

			if (++dirty == ctx->dirty)
				break;
		}
		if (dirty == ctx->dirty)
			break;
	}

	s->cx = cx;
	s->cy = cy;
}

/* Reset screen state. */
void
screen_write_reset(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;

	screen_reset_tabs(s);
	screen_write_scrollregion(ctx, 0, screen_size_y(s) - 1);

	s->mode &= ~(MODE_INSERT|MODE_KCURSOR|MODE_KKEYPAD|MODE_FOCUSON);
	s->mode &= ~(ALL_MOUSE_MODES|MODE_MOUSE_UTF8|MODE_MOUSE_SGR);

	screen_write_clearscreen(ctx);
	screen_write_cursormove(ctx, 0, 0);
}

/* Write character. */
void
screen_write_putc(struct screen_write_ctx *ctx, const struct grid_cell *gcp,
    u_char ch)
{
	struct grid_cell	gc;

	memcpy(&gc, gcp, sizeof gc);

	utf8_set(&gc.data, ch);
	screen_write_cell(ctx, &gc);
}

/* Calculate string length, with embedded formatting. */
size_t
screen_write_cstrlen(const char *fmt, ...)
{
	va_list	ap;
	char   *msg, *msg2, *ptr, *ptr2;
	size_t	size;

	va_start(ap, fmt);
	xvasprintf(&msg, fmt, ap);
	va_end(ap);
	msg2 = xmalloc(strlen(msg) + 1);

	ptr = msg;
	ptr2 = msg2;
	while (*ptr != '\0') {
		if (ptr[0] == '#' && ptr[1] == '[') {
			while (*ptr != ']' && *ptr != '\0')
				ptr++;
			if (*ptr == ']')
				ptr++;
			continue;
		}
		*ptr2++ = *ptr++;
	}
	*ptr2 = '\0';

	size = screen_write_strlen("%s", msg2);

	free(msg);
	free(msg2);

	return (size);
}

/* Calculate string length. */
size_t
screen_write_strlen(const char *fmt, ...)
{
	va_list			ap;
	char   	       	       *msg;
	struct utf8_data	ud;
	u_char 	      	       *ptr;
	size_t			left, size = 0;
	enum utf8_state		more;

	va_start(ap, fmt);
	xvasprintf(&msg, fmt, ap);
	va_end(ap);

	ptr = msg;
	while (*ptr != '\0') {
		if (*ptr > 0x7f && utf8_open(&ud, *ptr) == UTF8_MORE) {
			ptr++;

			left = strlen(ptr);
			if (left < (size_t)ud.size - 1)
				break;
			while ((more = utf8_append(&ud, *ptr)) == UTF8_MORE)
				ptr++;
			ptr++;

			if (more == UTF8_DONE)
				size += ud.width;
		} else {
			if (*ptr > 0x1f && *ptr < 0x7f)
				size++;
			ptr++;
		}
	}

	free(msg);
	return (size);
}

/* Write simple string (no UTF-8 or maximum length). */
void
screen_write_puts(struct screen_write_ctx *ctx, const struct grid_cell *gcp,
    const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	screen_write_vnputs(ctx, -1, gcp, fmt, ap);
	va_end(ap);
}

/* Write string with length limit (-1 for unlimited). */
void
screen_write_nputs(struct screen_write_ctx *ctx, ssize_t maxlen,
    const struct grid_cell *gcp, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	screen_write_vnputs(ctx, maxlen, gcp, fmt, ap);
	va_end(ap);
}

void
screen_write_vnputs(struct screen_write_ctx *ctx, ssize_t maxlen,
    const struct grid_cell *gcp, const char *fmt, va_list ap)
{
	struct grid_cell	gc;
	struct utf8_data       *ud = &gc.data;
	char   		       *msg;
	u_char 		       *ptr;
	size_t		 	left, size = 0;
	enum utf8_state		more;

	memcpy(&gc, gcp, sizeof gc);
	xvasprintf(&msg, fmt, ap);

	ptr = msg;
	while (*ptr != '\0') {
		if (*ptr > 0x7f && utf8_open(ud, *ptr) == UTF8_MORE) {
			ptr++;

			left = strlen(ptr);
			if (left < (size_t)ud->size - 1)
				break;
			while ((more = utf8_append(ud, *ptr)) == UTF8_MORE)
				ptr++;
			ptr++;

			if (more != UTF8_DONE)
				continue;
			if (maxlen > 0 && size + ud->width > (size_t)maxlen) {
				while (size < (size_t)maxlen) {
					screen_write_putc(ctx, &gc, ' ');
					size++;
				}
				break;
			}
			size += ud->width;
			screen_write_cell(ctx, &gc);
		} else {
			if (maxlen > 0 && size + 1 > (size_t)maxlen)
				break;

			if (*ptr == '\001')
				gc.attr ^= GRID_ATTR_CHARSET;
			else if (*ptr > 0x1f && *ptr < 0x7f) {
				size++;
				screen_write_putc(ctx, &gc, *ptr);
			}
			ptr++;
		}
	}

	free(msg);
}

/* Write string, similar to nputs, but with embedded formatting (#[]). */
void
screen_write_cnputs(struct screen_write_ctx *ctx, ssize_t maxlen,
    const struct grid_cell *gcp, const char *fmt, ...)
{
	struct grid_cell	 gc;
	struct utf8_data	*ud = &gc.data;
	va_list			 ap;
	char			*msg;
	u_char 			*ptr, *last;
	size_t			 left, size = 0;
	enum utf8_state		 more;

	memcpy(&gc, gcp, sizeof gc);

	va_start(ap, fmt);
	xvasprintf(&msg, fmt, ap);
	va_end(ap);

	ptr = msg;
	while (*ptr != '\0') {
		if (ptr[0] == '#' && ptr[1] == '[') {
			ptr += 2;
			last = ptr + strcspn(ptr, "]");
			if (*last == '\0') {
				/* No ]. Not much point in doing anything. */
				break;
			}
			*last = '\0';

			style_parse(gcp, &gc, ptr);
			ptr = last + 1;
			continue;
		}

		if (*ptr > 0x7f && utf8_open(ud, *ptr) == UTF8_MORE) {
			ptr++;

			left = strlen(ptr);
			if (left < (size_t)ud->size - 1)
				break;
			while ((more = utf8_append(ud, *ptr)) == UTF8_MORE)
				ptr++;
			ptr++;

			if (more != UTF8_DONE)
				continue;
			if (maxlen > 0 && size + ud->width > (size_t)maxlen) {
				while (size < (size_t)maxlen) {
					screen_write_putc(ctx, &gc, ' ');
					size++;
				}
				break;
			}
			size += ud->width;
			screen_write_cell(ctx, &gc);
		} else {
			if (maxlen > 0 && size + 1 > (size_t)maxlen)
				break;

			if (*ptr > 0x1f && *ptr < 0x7f) {
				size++;
				screen_write_putc(ctx, &gc, *ptr);
			}
			ptr++;
		}
	}

	free(msg);
}

/* Copy from another screen. */
void
screen_write_copy(struct screen_write_ctx *ctx,
    struct screen *src, u_int px, u_int py, u_int nx, u_int ny)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = src->grid;
	struct grid_line	*gl;
	struct grid_cell	 gc;
	u_int		 	 xx, yy, cx, cy, ax, bx;

	cx = s->cx;
	cy = s->cy;
	for (yy = py; yy < py + ny; yy++) {
		gl = &gd->linedata[yy];
		if (yy < gd->hsize + gd->sy) {
			/*
			 * Find start and end position and copy between
			 * them. Limit to the real end of the line then use a
			 * clear EOL only if copying to the end, otherwise
			 * could overwrite whatever is there already.
			 */
			if (px > gl->cellsize)
				ax = gl->cellsize;
			else
				ax = px;
			if (px + nx == gd->sx && px + nx > gl->cellsize)
				bx = gl->cellsize;
			else
				bx = px + nx;

			for (xx = ax; xx < bx; xx++) {
				grid_get_cell(gd, xx, yy, &gc);
				screen_write_cell(ctx, &gc);
			}
			if (px + nx == gd->sx && px + nx > gl->cellsize)
				screen_write_clearendofline(ctx);
		} else
			screen_write_clearline(ctx);
		cy++;
		screen_write_cursormove(ctx, cx, cy);
	}
}

/* Set up context for TTY command. */
static void
screen_write_initctx(struct screen_write_ctx *ctx, struct tty_ctx *ttyctx)
{
	struct screen	*s = ctx->s;

	ttyctx->wp = ctx->wp;

	ttyctx->ocx = s->cx;
	ttyctx->ocy = s->cy;

	ttyctx->orlower = s->rlower;
	ttyctx->orupper = s->rupper;
}

/* Save last cell on screen. */
static void
screen_write_save_last(struct screen_write_ctx *ctx, struct tty_ctx *ttyctx)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = s->grid;
	struct grid_cell	 gc;
	u_int			 xx;

	memcpy(&gc, &grid_default_cell, sizeof gc);
	for (xx = 1; xx <= screen_size_x(s); xx++) {
		grid_view_get_cell(gd, screen_size_x(s) - xx, s->cy, &gc);
		if (~gc.flags & GRID_FLAG_PADDING)
			break;
	}
	memcpy(&ttyctx->last_cell, &gc, sizeof ttyctx->last_cell);
}

/* Set a mode. */
void
screen_write_mode_set(struct screen_write_ctx *ctx, int mode)
{
	struct screen	*s = ctx->s;

	s->mode |= mode;
}

/* Clear a mode. */
void
screen_write_mode_clear(struct screen_write_ctx *ctx, int mode)
{
	struct screen	*s = ctx->s;

	s->mode &= ~mode;
}

/* Cursor up by ny. */
void
screen_write_cursorup(struct screen_write_ctx *ctx, u_int ny)
{
	struct screen	*s = ctx->s;

	if (ny == 0)
		ny = 1;

	if (s->cy < s->rupper) {
		/* Above region. */
		if (ny > s->cy)
			ny = s->cy;
	} else {
		/* Below region. */
		if (ny > s->cy - s->rupper)
			ny = s->cy - s->rupper;
	}
	if (s->cx == screen_size_x(s))
	    s->cx--;
	if (ny == 0)
		return;

	s->cy -= ny;
}

/* Cursor down by ny. */
void
screen_write_cursordown(struct screen_write_ctx *ctx, u_int ny)
{
	struct screen	*s = ctx->s;

	if (ny == 0)
		ny = 1;

	if (s->cy > s->rlower) {
		/* Below region. */
		if (ny > screen_size_y(s) - 1 - s->cy)
			ny = screen_size_y(s) - 1 - s->cy;
	} else {
		/* Above region. */
		if (ny > s->rlower - s->cy)
			ny = s->rlower - s->cy;
	}
	if (s->cx == screen_size_x(s))
	    s->cx--;
	if (ny == 0)
		return;

	s->cy += ny;
}

/* Cursor right by nx.  */
void
screen_write_cursorright(struct screen_write_ctx *ctx, u_int nx)
{
	struct screen	*s = ctx->s;

	if (nx == 0)
		nx = 1;

	if (nx > screen_size_x(s) - 1 - s->cx)
		nx = screen_size_x(s) - 1 - s->cx;
	if (nx == 0)
		return;

	s->cx += nx;
}

/* Cursor left by nx. */
void
screen_write_cursorleft(struct screen_write_ctx *ctx, u_int nx)
{
	struct screen	*s = ctx->s;

	if (nx == 0)
		nx = 1;

	if (nx > s->cx)
		nx = s->cx;
	if (nx == 0)
		return;

	s->cx -= nx;
}

/* Backspace; cursor left unless at start of wrapped line when can move up. */
void
screen_write_backspace(struct screen_write_ctx *ctx)
{
	struct screen		*s = ctx->s;
	struct grid_line	*gl;

	if (s->cx == 0) {
		if (s->cy == 0)
			return;
		gl = &s->grid->linedata[s->grid->hsize + s->cy - 1];
		if (gl->flags & GRID_LINE_WRAPPED) {
			s->cy--;
			s->cx = screen_size_x(s) - 1;
		}
	} else
		s->cx--;
}

/* VT100 alignment test. */
void
screen_write_alignmenttest(struct screen_write_ctx *ctx)
{
	struct screen		*s = ctx->s;
	struct tty_ctx	 	 ttyctx;
	struct grid_cell       	 gc;
	u_int			 xx, yy;
	u_int		 	 sx = screen_size_x(s), sy = screen_size_y(s);

	screen_write_initctx(ctx, &ttyctx);

	screen_dirty_clear(s, 0, 0, sx - 1, sy  - 1);

	memcpy(&gc, &grid_default_cell, sizeof gc);
	utf8_set(&gc.data, 'E');

	for (yy = 0; yy < screen_size_y(s); yy++) {
		for (xx = 0; xx < screen_size_x(s); xx++)
			grid_view_set_cell(s->grid, xx, yy, &gc);
	}

	s->cx = 0;
	s->cy = 0;

	s->rupper = 0;
	s->rlower = screen_size_y(s) - 1;

	tty_write(tty_cmd_alignmenttest, &ttyctx);
}

/* Insert nx characters. */
void
screen_write_insertcharacter(struct screen_write_ctx *ctx, u_int nx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	if (nx == 0)
		nx = 1;

	if (nx > screen_size_x(s) - s->cx)
		nx = screen_size_x(s) - s->cx;
	if (nx == 0)
		return;

	screen_write_flush(ctx);
	screen_write_initctx(ctx, &ttyctx);

	if (s->cx <= screen_size_x(s) - 1)
		grid_view_insert_cells(s->grid, s->cx, s->cy, nx);

	ttyctx.num = nx;
	tty_write(tty_cmd_insertcharacter, &ttyctx);
}

/* Delete nx characters. */
void
screen_write_deletecharacter(struct screen_write_ctx *ctx, u_int nx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	if (nx == 0)
		nx = 1;

	if (nx > screen_size_x(s) - s->cx)
		nx = screen_size_x(s) - s->cx;
	if (nx == 0)
		return;

	screen_write_flush(ctx);
	screen_write_initctx(ctx, &ttyctx);

	if (s->cx <= screen_size_x(s) - 1)
		grid_view_delete_cells(s->grid, s->cx, s->cy, nx);

	ttyctx.num = nx;
	tty_write(tty_cmd_deletecharacter, &ttyctx);
}

/* Clear nx characters. */
void
screen_write_clearcharacter(struct screen_write_ctx *ctx, u_int nx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	if (nx == 0)
		nx = 1;

	if (nx > screen_size_x(s) - s->cx)
		nx = screen_size_x(s) - s->cx;
	if (nx == 0)
		return;

	screen_write_initctx(ctx, &ttyctx);

	if (s->cx <= screen_size_x(s) - 1) {
		screen_dirty_clear(s, s->cx, s->cy, s->cx + nx - 1, s->cy);
		grid_view_clear(s->grid, s->cx, s->cy, nx, 1);
	} else
		return;

	ttyctx.num = nx;
	tty_write(tty_cmd_clearcharacter, &ttyctx);
}

/* Insert ny lines. */
void
screen_write_insertline(struct screen_write_ctx *ctx, u_int ny)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	if (ny == 0)
		ny = 1;

	if (s->cy < s->rupper || s->cy > s->rlower) {
		if (ny > screen_size_y(s) - s->cy)
			ny = screen_size_y(s) - s->cy;
		if (ny == 0)
			return;

		screen_write_flush(ctx);
		screen_write_initctx(ctx, &ttyctx);

		grid_view_insert_lines(s->grid, s->cy, ny);

		ttyctx.num = ny;
		tty_write(tty_cmd_insertline, &ttyctx);
		return;
	}

	if (ny > s->rlower + 1 - s->cy)
		ny = s->rlower + 1 - s->cy;
	if (ny == 0)
		return;

	screen_write_flush(ctx);
	screen_write_initctx(ctx, &ttyctx);

	if (s->cy < s->rupper || s->cy > s->rlower)
		grid_view_insert_lines(s->grid, s->cy, ny);
	else
		grid_view_insert_lines_region(s->grid, s->rlower, s->cy, ny);

	ttyctx.num = ny;
	tty_write(tty_cmd_insertline, &ttyctx);
}

/* Delete ny lines. */
void
screen_write_deleteline(struct screen_write_ctx *ctx, u_int ny)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	if (ny == 0)
		ny = 1;

	if (s->cy < s->rupper || s->cy > s->rlower) {
		if (ny > screen_size_y(s) - s->cy)
			ny = screen_size_y(s) - s->cy;
		if (ny == 0)
			return;

		screen_write_flush(ctx);
		screen_write_initctx(ctx, &ttyctx);

		grid_view_delete_lines(s->grid, s->cy, ny);

		ttyctx.num = ny;
		tty_write(tty_cmd_deleteline, &ttyctx);
		return;
	}

	if (ny > s->rlower + 1 - s->cy)
		ny = s->rlower + 1 - s->cy;
	if (ny == 0)
		return;

	screen_write_flush(ctx);
	screen_write_initctx(ctx, &ttyctx);

	if (s->cy < s->rupper || s->cy > s->rlower)
		grid_view_delete_lines(s->grid, s->cy, ny);
	else
		grid_view_delete_lines_region(s->grid, s->rlower, s->cy, ny);

	ttyctx.num = ny;
	tty_write(tty_cmd_deleteline, &ttyctx);
}

/* Clear line at cursor. */
void
screen_write_clearline(struct screen_write_ctx *ctx)
{
	struct screen		*s = ctx->s;
	struct grid_line	*gl;
	struct tty_ctx		 ttyctx;
	u_int			 sx = screen_size_x(s);

	screen_write_initctx(ctx, &ttyctx);

	gl = &s->grid->linedata[s->grid->hsize + s->cy];
	if (gl->cellsize != 0) {
		screen_dirty_clear(s, 0, s->cy, sx - 1, s->cy);
		grid_view_clear(s->grid, 0, s->cy, sx, 1);
	} else
		return;

	tty_write(tty_cmd_clearline, &ttyctx);
}

/* Clear to end of line from cursor. */
void
screen_write_clearendofline(struct screen_write_ctx *ctx)
{
	struct screen		*s = ctx->s;
	struct grid_line	*gl;
	struct tty_ctx		 ttyctx;
	u_int			 sx = screen_size_x(s);

	screen_write_initctx(ctx, &ttyctx);

	gl = &s->grid->linedata[s->grid->hsize + s->cy];
	if (s->cx <= sx - 1 && s->cx < gl->cellsize) {
		screen_dirty_clear(s, s->cx, s->cy, sx - 1, s->cy);
		grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 1);
	} else
		return;

	tty_write(tty_cmd_clearendofline, &ttyctx);
}

/* Clear to start of line from cursor. */
void
screen_write_clearstartofline(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;
	u_int		 sx = screen_size_x(s);

	screen_write_initctx(ctx, &ttyctx);

	if (s->cx > sx - 1) {
		screen_dirty_clear(s, 0, s->cy, sx - 1, s->cy);
		grid_view_clear(s->grid, 0, s->cy, sx, 1);
	} else {
		screen_dirty_clear(s, 0, s->cy, s->cx, s->cy);
		grid_view_clear(s->grid, 0, s->cy, s->cx + 1, 1);
	}

	tty_write(tty_cmd_clearstartofline, &ttyctx);
}

/* Move cursor to px,py.  */
void
screen_write_cursormove(struct screen_write_ctx *ctx, u_int px, u_int py)
{
	struct screen	*s = ctx->s;

	if (px > screen_size_x(s) - 1)
		px = screen_size_x(s) - 1;
	if (py > screen_size_y(s) - 1)
		py = screen_size_y(s) - 1;

	s->cx = px;
	s->cy = py;
}

/* Reverse index (up with scroll).  */
void
screen_write_reverseindex(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;

	screen_write_initctx(ctx, &ttyctx);

	if (s->cy == s->rupper) {
		screen_write_flush(ctx);
		grid_view_scroll_region_down(s->grid, s->rupper, s->rlower);
	} else if (s->cy > 0)
		s->cy--;

	tty_write(tty_cmd_reverseindex, &ttyctx);
}

/* Set scroll region. */
void
screen_write_scrollregion(struct screen_write_ctx *ctx, u_int rupper,
    u_int rlower)
{
	struct screen	*s = ctx->s;

	if (rupper > screen_size_y(s) - 1)
		rupper = screen_size_y(s) - 1;
	if (rlower > screen_size_y(s) - 1)
		rlower = screen_size_y(s) - 1;
	if (rupper >= rlower)	/* cannot be one line */
		return;

	/* Cursor moves to top-left. */
	s->cx = 0;
	s->cy = 0;

	s->rupper = rupper;
	s->rlower = rlower;
}

/* Line feed. */
void
screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped)
{
	struct screen		*s = ctx->s;
	struct grid_line	*gl;
	struct tty_ctx	 	 ttyctx;
	u_int			 sx = screen_size_x(s), sy = screen_size_y(s);

	screen_write_initctx(ctx, &ttyctx);

	gl = &s->grid->linedata[s->grid->hsize + s->cy];
	if (wrapped)
		gl->flags |= GRID_LINE_WRAPPED;
	else
		gl->flags &= ~GRID_LINE_WRAPPED;

	if (s->cy == s->rlower) {
		screen_dirty_clear(s, 0, s->rupper, sx - 1, s->rupper);
		screen_write_flush(ctx);
		grid_view_scroll_region_up(s->grid, s->rupper, s->rlower);
	} else if (s->cy < sy - 1)
		s->cy++;

	ttyctx.num = wrapped;
	tty_write(tty_cmd_linefeed, &ttyctx);
}

/* Carriage return (cursor to start of line). */
void
screen_write_carriagereturn(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;

	s->cx = 0;
}

/* Clear to end of screen from cursor. */
void
screen_write_clearendofscreen(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;
	u_int		 sx = screen_size_x(s), sy = screen_size_y(s);

	screen_write_initctx(ctx, &ttyctx);

	/* Scroll into history if it is enabled and clearing entire screen. */
	if (s->cy == 0 && s->grid->flags & GRID_HISTORY) {
		screen_dirty_clear(s, 0, 0, sx - 1, sy  - 1);
		grid_view_clear_history(s->grid);
	} else {
		if (s->cx <= sx - 1) {
			screen_dirty_clear(s, s->cx, s->cy, sx - 1, s->cy);
			grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 1);
		}
		screen_dirty_clear(s, 0, s->cy + 1, sx - 1, sy - 1);
		grid_view_clear(s->grid, 0, s->cy + 1, sx, sy - (s->cy + 1));
	}

	tty_write(tty_cmd_clearendofscreen, &ttyctx);
}

/* Clear to start of screen. */
void
screen_write_clearstartofscreen(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;
	u_int		 sx = screen_size_x(s);

	screen_write_initctx(ctx, &ttyctx);

	if (s->cy > 0) {
		screen_dirty_clear(s, 0, 0, sx - 1, s->cy);
		grid_view_clear(s->grid, 0, 0, sx, s->cy);
	}
	if (s->cx > sx - 1) {
		screen_dirty_clear(s, 0, s->cy, sx - 1, s->cy);
		grid_view_clear(s->grid, 0, s->cy, sx, 1);
	} else {
		screen_dirty_clear(s, 0, s->cy, s->cx, s->cy);
		grid_view_clear(s->grid, 0, s->cy, s->cx + 1, 1);
	}

	tty_write(tty_cmd_clearstartofscreen, &ttyctx);
}

/* Clear entire screen. */
void
screen_write_clearscreen(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct tty_ctx	 ttyctx;
	u_int		 sx = screen_size_x(s), sy = screen_size_y(s);

	screen_write_initctx(ctx, &ttyctx);

	screen_dirty_clear(s, 0, 0, sx - 1, sy  - 1);

	/* Scroll into history if it is enabled. */
	if (s->grid->flags & GRID_HISTORY)
		grid_view_clear_history(s->grid);
	else
		grid_view_clear(s->grid, 0, 0, sx, sy);

	tty_write(tty_cmd_clearscreen, &ttyctx);
}

/* Clear entire history. */
void
screen_write_clearhistory(struct screen_write_ctx *ctx)
{
	struct screen	*s = ctx->s;
	struct grid	*gd = s->grid;

	grid_move_lines(gd, 0, gd->hsize, gd->sy);
	gd->hsize = 0;
}

/* Write cell data. */
void
screen_write_cell(struct screen_write_ctx *ctx, const struct grid_cell *gc)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = s->grid;
	struct tty_ctx		 ttyctx;
	u_int		 	 width, xx, last;
	u_int			 sx = screen_size_x(s), sy = screen_size_y(s);
	struct grid_line	*gl;
	struct grid_cell 	 tmp_gc, now_gc;
	struct grid_cell_entry	*gce;
	int			 insert, skip, selected, wrapped = 0;

	ctx->cells++;

	/* Ignore padding. */
	if (gc->flags & GRID_FLAG_PADDING)
		return;
	width = gc->data.width;

	/*
	 * If this is a wide character and there is no room on the screen, for
	 * the entire character, don't print it.
	 */
	if (!(s->mode & MODE_WRAP) && (width > 1 &&
	    (width > sx || (s->cx != sx && s->cx > sx - width))))
		return;

	/*
	 * If the width is zero, combine onto the previous character, if
	 * there is space.
	 */
	if (width == 0) {
		if (screen_write_combine(ctx, &gc->data) == 0) {
			screen_write_initctx(ctx, &ttyctx);
			tty_write(tty_cmd_utf8character, &ttyctx);
		}
		return;
	}

	/* Initialise the redraw context. */
	screen_write_initctx(ctx, &ttyctx);

	/* If in insert mode, make space for the cells. */
	if ((s->mode & MODE_INSERT) && s->cx <= sx - width) {
		xx = sx - s->cx - width;
		grid_move_cells(s->grid, s->cx + width, s->cx, s->cy, xx);
		insert = 1;
	} else
		insert = 0;
	skip = !insert;

	/* Check this will fit on the current line and wrap if not. */
	if ((s->mode & MODE_WRAP) && s->cx > sx - width) {
		screen_write_flush(ctx);
		screen_write_save_last(ctx, &ttyctx);
		screen_write_linefeed(ctx, 1);
		s->cx = 0;	/* carriage return */
		skip = 0;
		wrapped = 1;
	}

	/* Sanity check cursor position. */
	if (s->cx > sx - width || s->cy > sy - 1)
		return;

	/* Handle overwriting of UTF-8 characters. */
	gl = &s->grid->linedata[s->grid->hsize + s->cy];
	if (gl->flags & GRID_LINE_EXTENDED) {
		grid_view_get_cell(gd, s->cx, s->cy, &now_gc);
		if (screen_write_overwrite(ctx, &now_gc, width))
			skip = 0;
	}

	/*
	 * If the new character is UTF-8 wide, fill in padding cells. Have
	 * already ensured there is enough room.
	 */
	for (xx = s->cx + 1; xx < s->cx + width; xx++) {
		grid_view_set_cell(gd, xx, s->cy, &screen_write_pad_cell);
		skip = 0;
	}

	/* If no change, do not draw. */
	if (skip) {
		if (s->cx >= gl->cellsize)
			skip = grid_cells_equal(gc, &grid_default_cell);
		else {
			gce = &gl->celldata[s->cx];
			if (gce->flags & GRID_FLAG_EXTENDED)
				skip = 0;
			else if (gc->flags != (gce->flags & ~GRID_FLAG_EXTENDED))
				skip = 0;
			else if (gc->attr != gce->data.attr)
				skip = 0;
			else if (gc->fg != gce->data.fg)
				skip = 0;
			else if (gc->bg != gce->data.bg)
				skip = 0;
			else if (gc->data.width != 1 || gce->data.data != gc->data.data[0])
				skip = 0;
		}
	}

	/* Update the selection the flag and set the cell. */
	selected = screen_check_selection(s, s->cx, s->cy);
	if (selected && ~gc->flags & GRID_FLAG_SELECTED) {
		skip = 0;
		memcpy(&tmp_gc, gc, sizeof tmp_gc);
		tmp_gc.flags |= GRID_FLAG_SELECTED;
		grid_view_set_cell(gd, s->cx, s->cy, &tmp_gc);
	} else if (!selected && gc->flags & GRID_FLAG_SELECTED) {
		skip = 0;
		memcpy(&tmp_gc, gc, sizeof tmp_gc);
		tmp_gc.flags &= ~GRID_FLAG_SELECTED;
		grid_view_set_cell(gd, s->cx, s->cy, &tmp_gc);
	} else if (!skip)
		grid_view_set_cell(gd, s->cx, s->cy, gc);

	/*
	 * Move the cursor. If not wrapping, stick at the last character and
	 * replace it.
	 */
	last = !(s->mode & MODE_WRAP);
	if (s->cx <= sx - last - width)
		s->cx += width;
	else
		s->cx = sx - last;

	/* Create space for character in insert mode. */
	if (insert) {
		if (!wrapped)
			screen_write_flush(ctx);
		ttyctx.num = width;
		tty_write(tty_cmd_insertcharacter, &ttyctx);
	}

	/* Write to the screen. */
	if (selected) {
		memcpy(&tmp_gc, &s->sel.cell, sizeof tmp_gc);
		utf8_copy(&tmp_gc.data, &gc->data);
		tmp_gc.attr = tmp_gc.attr & ~GRID_ATTR_CHARSET;
		tmp_gc.attr |= gc->attr & GRID_ATTR_CHARSET;
		tmp_gc.flags = gc->flags;
		screen_write_flush(ctx);
		ttyctx.cell = &tmp_gc;
		tty_write(tty_cmd_cell, &ttyctx);
		ctx->written++;
	} else if (!skip) {
		if (wrapped) {
			ttyctx.cell = gc;
			tty_write(tty_cmd_cell, &ttyctx);
			ctx->written++;
		} else {
			/*
			 * If wp is NULL, we are not updating the terminal and
			 * don't care about actually writing the cells
			 * (tty_write will just return). So don't even bother
			 * allocating the dirty array.
			 */
			if (ctx->wp != NULL && s->dirty == NULL) {
				log_debug("%s: allocating %u bits", __func__,
				    s->dirtysize);
				s->dirty = bit_alloc(s->dirtysize);
			}
			if (s->dirty != NULL) {
				bit_set(s->dirty, screen_dirty_bit(s,
				    ttyctx.ocx, ttyctx.ocy));
				ctx->dirty++;
			}
		}
	} else
		ctx->skipped++;
}

/* Combine a UTF-8 zero-width character onto the previous. */
static int
screen_write_combine(struct screen_write_ctx *ctx, const struct utf8_data *ud)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = s->grid;
	struct grid_cell	 gc;

	/* Can't combine if at 0. */
	if (s->cx == 0)
		return (-1);

	/* Empty data is out. */
	if (ud->size == 0)
		fatalx("UTF-8 data empty");

	/* Retrieve the previous cell. */
	grid_view_get_cell(gd, s->cx - 1, s->cy, &gc);

	/* Check there is enough space. */
	if (gc.data.size + ud->size > sizeof gc.data.data)
		return (-1);

	/* Append the data. */
	memcpy(gc.data.data + gc.data.size, ud->data, ud->size);
	gc.data.size += ud->size;

	/* Set the new cell. */
	grid_view_set_cell(gd, s->cx - 1, s->cy, &gc);

	return (0);
}

/*
 * UTF-8 wide characters are a bit of an annoyance. They take up more than one
 * cell on the screen, so following cells must not be drawn by marking them as
 * padding.
 *
 * So far, so good. The problem is, when overwriting a padding cell, or a UTF-8
 * character, it is necessary to also overwrite any other cells which covered
 * by the same character.
 */
static int
screen_write_overwrite(struct screen_write_ctx *ctx, struct grid_cell *gc,
    u_int width)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = s->grid;
	struct grid_cell	 tmp_gc;
	u_int			 xx;
	int			 done = 0;

	if (gc->flags & GRID_FLAG_PADDING) {
		/*
		 * A padding cell, so clear any following and leading padding
		 * cells back to the character. Don't overwrite the current
		 * cell as that happens later anyway.
		 */
		xx = s->cx + 1;
		while (--xx > 0) {
			grid_view_get_cell(gd, xx, s->cy, &tmp_gc);
			if (~tmp_gc.flags & GRID_FLAG_PADDING)
				break;
			grid_view_set_cell(gd, xx, s->cy, &grid_default_cell);
		}

		/* Overwrite the character at the start of this padding. */
		grid_view_set_cell(gd, xx, s->cy, &grid_default_cell);
		done = 1;
	}

	/*
	 * Overwrite any padding cells that belong to a UTF-8 character
	 * we'll be overwriting with the current character.
	 */
	if (gc->data.width != 1 || gc->flags & GRID_FLAG_PADDING) {
		xx = s->cx + width - 1;
		while (++xx < screen_size_x(s)) {
			grid_view_get_cell(gd, xx, s->cy, &tmp_gc);
			if (~tmp_gc.flags & GRID_FLAG_PADDING)
				break;
			grid_view_set_cell(gd, xx, s->cy, &grid_default_cell);
			done = 1;
		}
	}

	return (done);
}

void
screen_write_setselection(struct screen_write_ctx *ctx, u_char *str, u_int len)
{
	struct tty_ctx	ttyctx;

	screen_write_initctx(ctx, &ttyctx);
	ttyctx.ptr = str;
	ttyctx.num = len;

	tty_write(tty_cmd_setselection, &ttyctx);
}

void
screen_write_rawstring(struct screen_write_ctx *ctx, u_char *str, u_int len)
{
	struct tty_ctx	ttyctx;

	screen_write_initctx(ctx, &ttyctx);
	ttyctx.ptr = str;
	ttyctx.num = len;

	tty_write(tty_cmd_rawstring, &ttyctx);
}