Return to screen-write.c CVS log

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

When drawing lines that have wrapped naturally, don't force a newline but
permit them to wrap naturally again. This allows terminals that use this to
guess where lines start and end for eg mouse selecting (like xterm) to work
correctly.

This was another long-standing issue raised by several people over the last
while.

Thanks to martynas@ for much testing. This was not trivial to get right so
bringing it in for wider testing and adn to fix any further glitches in-tree.

/* $OpenBSD: screen-write.c,v 1.30 2009/10/12 17:19:47 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 <string.h>

#include "tmux.h"

void	screen_write_initctx(struct screen_write_ctx *, struct tty_ctx *);
void	screen_write_overwrite(struct screen_write_ctx *);

/* Initialise writing with a window. */
void
screen_write_start(
    struct screen_write_ctx *ctx, struct window_pane *wp, struct screen *s)
{
	ctx->wp = wp;
	if (wp != NULL && s == NULL)
		ctx->s = wp->screen;
	else
		ctx->s = s;
}

/* Finish writing. */
void
screen_write_stop(unused struct screen_write_ctx *ctx)
{
}

/* Write character. */
void
screen_write_putc(
    struct screen_write_ctx *ctx, struct grid_cell *gc, u_char ch)
{
	gc->data = ch;
	screen_write_cell(ctx, gc, NULL);
}

/* Calculate string length, with embedded formatting. */
size_t printflike2
screen_write_cstrlen(int utf8flag, 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(utf8flag, "%s", msg2);

	xfree(msg);
	xfree(msg2);

	return (size);
}

/* Calculate string length. */
size_t printflike2
screen_write_strlen(int utf8flag, const char *fmt, ...)
{
	va_list	ap;
	char   *msg;
	u_char *ptr, utf8buf[4];
	size_t	left, size = 0;

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

	ptr = msg;
	while (*ptr != '\0') {
		if (utf8flag && *ptr > 0x7f) {
			memset(utf8buf, 0xff, sizeof utf8buf);

			left = strlen(ptr);
			if (*ptr >= 0xc2 && *ptr <= 0xdf && left >= 2) {
				memcpy(utf8buf, ptr, 2);
				ptr += 2;
			} else if (*ptr >= 0xe0 && *ptr <= 0xef && left >= 3) {
				memcpy(utf8buf, ptr, 3);
				ptr += 3;
			} else if (*ptr >= 0xf0 && *ptr <= 0xf4 && left >= 4) {
				memcpy(utf8buf, ptr, 4);
				ptr += 4;
			} else {
				*utf8buf = *ptr;
				ptr++;
			}
			size += utf8_width(utf8buf);
		} else {
			size++;
			ptr++;
		}
	}

	xfree(msg);
	return (size);
}

/* Write simple string (no UTF-8 or maximum length). */
void printflike3
screen_write_puts(
    struct screen_write_ctx *ctx, struct grid_cell *gc, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	screen_write_vnputs(ctx, -1, gc, 0, fmt, ap);
	va_end(ap);
}

/* Write string with length limit (-1 for unlimited). */
void printflike5
screen_write_nputs(struct screen_write_ctx *ctx,
    ssize_t maxlen, struct grid_cell *gc, int utf8flag, const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	screen_write_vnputs(ctx, maxlen, gc, utf8flag, fmt, ap);
	va_end(ap);
}

void
screen_write_vnputs(struct screen_write_ctx *ctx, ssize_t maxlen,
    struct grid_cell *gc, int utf8flag, const char *fmt, va_list ap)
{
	char   *msg;
	u_char *ptr, utf8buf[4];
	size_t	left, size = 0;
	int	width;

	xvasprintf(&msg, fmt, ap);

	ptr = msg;
	while (*ptr != '\0') {
		if (utf8flag && *ptr > 0x7f) {
			memset(utf8buf, 0xff, sizeof utf8buf);

			left = strlen(ptr);
			if (*ptr >= 0xc2 && *ptr <= 0xdf && left >= 2) {
				memcpy(utf8buf, ptr, 2);
				ptr += 2;
			} else if (*ptr >= 0xe0 && *ptr <= 0xef && left >= 3) {
				memcpy(utf8buf, ptr, 3);
				ptr += 3;
			} else if (*ptr >= 0xf0 && *ptr <= 0xf4 && left >= 4) {
				memcpy(utf8buf, ptr, 4);
				ptr += 4;
			} else {
				*utf8buf = *ptr;
				ptr++;
			}

			width = utf8_width(utf8buf);
			if (maxlen > 0 && size + width > (size_t) maxlen) {
				while (size < (size_t) maxlen) {
					screen_write_putc(ctx, gc, ' ');
					size++;
				}
				break;
			}
			size += width;

			gc->flags |= GRID_FLAG_UTF8;
			screen_write_cell(ctx, gc, utf8buf);
			gc->flags &= ~GRID_FLAG_UTF8;

		} else {
			if (maxlen > 0 && size + 1 > (size_t) maxlen)
				break;

			size++;
			screen_write_putc(ctx, gc, *ptr);
			ptr++;
		}
	}

	xfree(msg);
}

/* Write string, similar to nputs, but with embedded formatting (#[]). */
void printflike5
screen_write_cnputs(struct screen_write_ctx *ctx,
    ssize_t maxlen, struct grid_cell *gc, int utf8flag, const char *fmt, ...)
{
	struct grid_cell	 lgc;
	va_list			 ap;
	char			*msg;
	u_char 			*ptr, *last, utf8buf[4];
	size_t			 left, size = 0;
	int			 width;

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

	memcpy(&lgc, gc, sizeof lgc);

	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';

			screen_write_parsestyle(gc, &lgc, ptr);
			ptr = last + 1;
			continue;
		}

		if (utf8flag && *ptr > 0x7f) {
			memset(utf8buf, 0xff, sizeof utf8buf);

			left = strlen(ptr);
			if (*ptr >= 0xc2 && *ptr <= 0xdf && left >= 2) {
				memcpy(utf8buf, ptr, 2);
				ptr += 2;
			} else if (*ptr >= 0xe0 && *ptr <= 0xef && left >= 3) {
				memcpy(utf8buf, ptr, 3);
				ptr += 3;
			} else if (*ptr >= 0xf0 && *ptr <= 0xf4 && left >= 4) {
				memcpy(utf8buf, ptr, 4);
				ptr += 4;
			} else {
				*utf8buf = *ptr;
				ptr++;
			}

			width = utf8_width(utf8buf);
			if (maxlen > 0 && size + width > (size_t) maxlen) {
				while (size < (size_t) maxlen) {
					screen_write_putc(ctx, gc, ' ');
					size++;
				}
				break;
			}
			size += width;

			lgc.flags |= GRID_FLAG_UTF8;
			screen_write_cell(ctx, &lgc, utf8buf);
			lgc.flags &= ~GRID_FLAG_UTF8;

		} else {
			if (maxlen > 0 && size + 1 > (size_t) maxlen)
				break;

			size++;
			screen_write_putc(ctx, &lgc, *ptr);
			ptr++;
		}
	}

	xfree(msg);
}

/* Parse an embedded style of the form "fg=colour,bg=colour,bright,...". */
void
screen_write_parsestyle(
    struct grid_cell *defgc, struct grid_cell *gc, const char *in)
{
	const char	delimiters[] = " ,";
	char		tmp[32];
	int		val;
	size_t		end;
	u_char		fg, bg, attr, flags;

	if (*in == '\0')
		return;
	if (strchr(delimiters, in[strlen(in) - 1]) != NULL)
		return;

	fg = gc->fg;
	bg = gc->bg;
	attr = gc->attr;
	flags = gc->flags;
	do {
		end = strcspn(in, delimiters);
		if (end > (sizeof tmp) - 1)
			return;
		memcpy(tmp, in, end);
		tmp[end] = '\0';

		if (strcasecmp(tmp, "default") == 0) {
			fg = defgc->fg;
			bg = defgc->bg;
			attr = defgc->attr;
		} else if (end > 3 && strncasecmp(tmp + 1, "g=", 2) == 0) {
			if ((val = colour_fromstring(tmp + 3)) == -1)
				return;
			if (*in == 'f' || *in == 'F') {
				if (val != 8) {
					if (val & 0x100) {
						flags |= GRID_FLAG_FG256;
						val &= ~0x100;
					} else
						flags &= ~GRID_FLAG_FG256;
					fg = val;
				} else
					fg = defgc->fg;
			} else if (*in == 'b' || *in == 'B') {
				if (val != 8) {
					if (val & 0x100) {
						flags |= GRID_FLAG_BG256;
						val &= ~0x100;
					} else
						flags &= ~GRID_FLAG_BG256;
					bg = val;
				} else
					bg = defgc->bg;
			} else
				return;
		} else if (end > 2 && strncasecmp(tmp, "no", 2) == 0) {
			if ((val = attributes_fromstring(tmp + 2)) == -1)
				return;
			attr &= ~val;
		} else {
			if ((val = attributes_fromstring(tmp)) == -1)
				return;
			attr |= val;
		}

		in += end + strspn(in + end, delimiters);
	} while (*in != '\0');
	gc->fg = fg;
	gc->bg = bg;
	gc->attr = attr;
	gc->flags = flags;
}

/* 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;
	const struct grid_cell	*gc;
	u_char			*udata;
	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++) {
				udata = NULL;
				if (xx >= gl->cellsize)
					gc = &grid_default_cell;
				else {
					gc = &gl->celldata[xx];
					if (gc->flags & GRID_FLAG_UTF8)
						udata = gl->utf8data[xx].data;
				}
				screen_write_cell(ctx, gc, udata);
			}
			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. */
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;
}

/* 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 (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 (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;

	screen_write_initctx(ctx, &ttyctx);

	memcpy(&gc, &grid_default_cell, sizeof gc);
	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_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_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);
}

/* 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_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_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_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_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 tty_ctx	 ttyctx;

	screen_write_initctx(ctx, &ttyctx);

	grid_view_clear(s->grid, 0, s->cy, screen_size_x(s), 1);

	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 tty_ctx	 ttyctx;
	u_int		 sx;

	screen_write_initctx(ctx, &ttyctx);

	sx = screen_size_x(s);

	if (s->cx <= sx - 1)
		grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 1);

 	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_write_initctx(ctx, &ttyctx);

	sx = screen_size_x(s);

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

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

	if (state)
		s->mode |= MODE_CURSOR;
	else
		s->mode &= ~MODE_CURSOR;
}

/* 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)
		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;
}

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

	if (state)
		s->mode |= MODE_INSERT;
	else
		s->mode &= ~MODE_INSERT;
}

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

	if (state)
		s->mode |= MODE_MOUSE;
	else
		s->mode &= ~MODE_MOUSE;
}

/*
 * Line feed the screen only (don't update the tty). Used for printing single
 * characters, where might want to let the scroll happen naturally.
 */
void
screen_write_linefeedscreen(struct screen_write_ctx *ctx, int wrapped)
{
	struct screen		*s = ctx->s;
	struct grid_line	*gl;

	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)
		grid_view_scroll_region_up(s->grid, s->rupper, s->rlower);
	else if (s->cy < screen_size_y(s) - 1)
		s->cy++;
}

/* Line feed (down with scroll). */
void
screen_write_linefeed(struct screen_write_ctx *ctx, int wrapped)
{
	struct tty_ctx	 ttyctx;

	screen_write_initctx(ctx, &ttyctx);

	screen_write_linefeedscreen(ctx, 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;
}

/* Set keypad cursor keys mode. */
void
screen_write_kcursormode(struct screen_write_ctx *ctx, int state)
{
	struct screen	*s = ctx->s;

	if (state)
		s->mode |= MODE_KCURSOR;
	else
		s->mode &= ~MODE_KCURSOR;
}

/* Set keypad number keys mode. */
void
screen_write_kkeypadmode(struct screen_write_ctx *ctx, int state)
{
	struct screen	*s = ctx->s;

	if (state)
		s->mode |= MODE_KKEYPAD;
	else
		s->mode &= ~MODE_KKEYPAD;
}

/* 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, sy;

	screen_write_initctx(ctx, &ttyctx);

	sx = screen_size_x(s);
	sy = screen_size_y(s);

	if (s->cx <= sx - 1)
		grid_view_clear(s->grid, s->cx, s->cy, sx - s->cx, 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_write_initctx(ctx, &ttyctx);

	sx = screen_size_x(s);

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

	screen_write_initctx(ctx, &ttyctx);

	grid_view_clear(s->grid, 0, 0, screen_size_x(s), screen_size_y(s));

	tty_write(tty_cmd_clearscreen, &ttyctx);
}

/* Write cell data. */
void
screen_write_cell(
    struct screen_write_ctx *ctx, const struct grid_cell *gc, u_char *udata)
{
	struct screen		*s = ctx->s;
	struct window_pane	*wp = ctx->wp;
	struct grid		*gd = s->grid;
	struct tty_ctx		 ttyctx;
	struct grid_utf8	 gu, *tmp_gu;
	u_int		 	 width, xx, i;
	struct grid_cell 	 tmp_gc, tmp_gc2, *tmp_gcp;
	int			 insert = 0;

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

	/* Find character width. */
	if (gc->flags & GRID_FLAG_UTF8) {
		width = utf8_width(udata);

		gu.width = width;
		memcpy(&gu.data, udata, sizeof gu.data);
 	} else
		width = 1;

	/* If the width is zero, combine onto the previous character. */
	if (width == 0) {
		if (s->cx == 0)
			return;
		tmp_gcp = grid_view_get_cell(gd, s->cx - 1, s->cy);
		if (!(tmp_gcp->flags & GRID_FLAG_UTF8)) {
			tmp_gcp->flags |= GRID_FLAG_UTF8;
			memset(&gu.data, 0xff, sizeof gu.data);
			*gu.data = tmp_gcp->data;
			gu.width = 1;
			grid_view_set_utf8(gd, s->cx - 1, s->cy, &gu);
		}
		tmp_gu = grid_view_get_utf8(gd, s->cx - 1, s->cy);

		for (i = 0; i < UTF8_SIZE; i++) {
			if (tmp_gu->data[i] == 0xff)
				break;
		}
		memcpy(tmp_gu->data + i, udata, UTF8_SIZE - i);

		/* Assume the previous character has just been input. */
		screen_write_initctx(ctx, &ttyctx);
		ttyctx.ptr = udata;
		tty_write(tty_cmd_utf8character, &ttyctx);
		return;
	}

	/* If the character is wider than the screen, don't print it. */
	if (width > screen_size_x(s)) {
		memcpy(&tmp_gc, gc, sizeof tmp_gc);
		tmp_gc.data = '_';
		width = 1;
		gc = &tmp_gc;
	}

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

	/* Check this will fit on the current line and wrap if not. */
	if (s->cx > screen_size_x(s) - width) {
		/* 
		 * Don't update the terminal now, just update the screen and
		 * leave the cursor to scroll naturally, unless this is only
		 * part of the screen width.
		 */
		if (wp->xoff != 0 || wp->sx != screen_size_x(s))
			screen_write_linefeed(ctx, 1);
		else
			screen_write_linefeedscreen(ctx, 1);
		s->cx = 0;	/* carriage return */
	}

	/* Sanity checks. */
	if (s->cx > screen_size_x(s) - 1 || s->cy > screen_size_y(s) - 1)
		return;

	/* Handle overwriting of UTF-8 characters. */
	screen_write_overwrite(ctx);

	/*
	 * 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++) {
		tmp_gcp = grid_view_get_cell(gd, xx, s->cy);
		if (tmp_gcp != NULL)
			tmp_gcp->flags |= GRID_FLAG_PADDING;
	}

	/* Set the cell. */
	grid_view_set_cell(gd, s->cx, s->cy, gc);
	if (gc->flags & GRID_FLAG_UTF8)
		grid_view_set_utf8(gd, s->cx, s->cy, &gu);

	/* Move the cursor. */
	screen_write_initctx(ctx, &ttyctx);
	s->cx += width;

	/* Draw to the screen if necessary. */
	if (insert) {
		ttyctx.num = width;
		tty_write(tty_cmd_insertcharacter, &ttyctx);
	}
	ttyctx.utf8 = &gu;
	if (screen_check_selection(s, s->cx - width, s->cy)) {
		memcpy(&tmp_gc2, &s->sel.cell, sizeof tmp_gc2);
		tmp_gc2.data = gc->data;
		tmp_gc2.flags = gc->flags &
		    ~(GRID_FLAG_FG256|GRID_FLAG_BG256);
		tmp_gc2.flags |= s->sel.cell.flags &
		    (GRID_FLAG_FG256|GRID_FLAG_BG256);
		ttyctx.cell = &tmp_gc2;
		tty_write(tty_cmd_cell, &ttyctx);
	} else {
		ttyctx.cell = gc;
		tty_write(tty_cmd_cell, &ttyctx);
	}
}

/*
 * 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.
 */
void
screen_write_overwrite(struct screen_write_ctx *ctx)
{
	struct screen		*s = ctx->s;
	struct grid		*gd = s->grid;
	const struct grid_cell	*gc;
	const struct grid_utf8	*gu;
	u_int			 xx;

	gc = grid_view_peek_cell(gd, s->cx, s->cy);
	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) {
			gc = grid_view_peek_cell(gd, xx, s->cy);
			if (!(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);

		/* Overwrite following padding cells. */
		xx = s->cx;
		while (++xx < screen_size_x(s)) {
			gc = grid_view_peek_cell(gd, xx, s->cy);
			if (!(gc->flags & GRID_FLAG_PADDING))
				break;
			grid_view_set_cell(gd, xx, s->cy, &grid_default_cell);
		}
	} else if (gc->flags & GRID_FLAG_UTF8) {
		gu = grid_view_peek_utf8(gd, s->cx, s->cy);
		if (gu->width > 1) {
			/*
			 * An UTF-8 wide cell; overwrite following padding cells only.
			 */
			xx = s->cx;
			while (++xx < screen_size_x(s)) {
				gc = grid_view_peek_cell(gd, xx, s->cy);
				if (!(gc->flags & GRID_FLAG_PADDING))
					break;
				grid_view_set_cell(gd, xx, s->cy, &grid_default_cell);
			}
		}
	}
}