Return to screen-redraw.c CVS log

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

Add a client flag 'active-pane' which stores the active pane in the
client and allows it to be changed independently from the real active
pane stored in the window. This is can be used with session groups which
allow an independent current window (although it would be nice to have a
flag for this too and remove session groups). The client active pane is
only really useful interactively, many things (hooks, window-style,
zooming) still use the window active pane.

/* $OpenBSD: screen-redraw.c,v 1.77 2020/05/16 16:20:59 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_redraw_draw_borders(struct screen_redraw_ctx *);
static void	screen_redraw_draw_panes(struct screen_redraw_ctx *);
static void	screen_redraw_draw_status(struct screen_redraw_ctx *);
static void	screen_redraw_draw_pane(struct screen_redraw_ctx *,
		    struct window_pane *);

#define CELL_INSIDE 0
#define CELL_LEFTRIGHT 1
#define CELL_TOPBOTTOM 2
#define CELL_TOPLEFT 3
#define CELL_TOPRIGHT 4
#define CELL_BOTTOMLEFT 5
#define CELL_BOTTOMRIGHT 6
#define CELL_TOPJOIN 7
#define CELL_BOTTOMJOIN 8
#define CELL_LEFTJOIN 9
#define CELL_RIGHTJOIN 10
#define CELL_JOIN 11
#define CELL_OUTSIDE 12

#define CELL_BORDERS " xqlkmjwvtun~"

const struct grid_cell screen_redraw_border_cell = {
	{ { ' ' }, 0, 1, 1 }, GRID_ATTR_CHARSET, 0, 8, 8, 0
};

enum screen_redraw_border_type {
	SCREEN_REDRAW_OUTSIDE,
	SCREEN_REDRAW_INSIDE,
	SCREEN_REDRAW_BORDER
};

/* Return if window has only two panes. */
static int
screen_redraw_two_panes(struct window *w, int direction)
{
	struct window_pane	*wp;

	wp = TAILQ_NEXT(TAILQ_FIRST(&w->panes), entry);
	if (wp == NULL)
		return (0); /* one pane */
	if (TAILQ_NEXT(wp, entry) != NULL)
		return (0); /* more than two panes */
	if (direction == 0 && wp->xoff == 0)
		return (0);
	if (direction == 1 && wp->yoff == 0)
		return (0);
	return (1);
}

/* Check if cell is on the border of a pane. */
static enum screen_redraw_border_type
screen_redraw_pane_border(struct window_pane *wp, u_int px, u_int py,
    int pane_status)
{
	u_int	ex = wp->xoff + wp->sx, ey = wp->yoff + wp->sy;

	/* Inside pane. */
	if (px >= wp->xoff && px < ex && py >= wp->yoff && py < ey)
		return (SCREEN_REDRAW_INSIDE);

	/* Left/right borders. */
	if (pane_status == PANE_STATUS_OFF) {
		if (screen_redraw_two_panes(wp->window, 0)) {
			if (wp->xoff == 0 && px == wp->sx && py <= wp->sy / 2)
				return (SCREEN_REDRAW_BORDER);
			if (wp->xoff != 0 &&
			    px == wp->xoff - 1 &&
			    py > wp->sy / 2)
				return (SCREEN_REDRAW_BORDER);
		} else {
			if ((wp->yoff == 0 || py >= wp->yoff - 1) && py <= ey) {
				if (wp->xoff != 0 && px == wp->xoff - 1)
					return (SCREEN_REDRAW_BORDER);
				if (px == ex)
					return (SCREEN_REDRAW_BORDER);
			}
		}
	} else {
		if ((wp->yoff == 0 || py >= wp->yoff - 1) && py <= ey) {
			if (wp->xoff != 0 && px == wp->xoff - 1)
				return (SCREEN_REDRAW_BORDER);
			if (px == ex)
				return (SCREEN_REDRAW_BORDER);
		}
	}

	/* Top/bottom borders. */
	if (pane_status == PANE_STATUS_OFF) {
		if (screen_redraw_two_panes(wp->window, 1)) {
			if (wp->yoff == 0 && py == wp->sy && px <= wp->sx / 2)
				return (SCREEN_REDRAW_BORDER);
			if (wp->yoff != 0 &&
			    py == wp->yoff - 1 &&
			    px > wp->sx / 2)
				return (SCREEN_REDRAW_BORDER);
		} else {
			if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
				if (wp->yoff != 0 && py == wp->yoff - 1)
					return (SCREEN_REDRAW_BORDER);
				if (py == ey)
					return (SCREEN_REDRAW_BORDER);
			}
		}
	} else if (pane_status == PANE_STATUS_TOP) {
		if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
			if (wp->yoff != 0 && py == wp->yoff - 1)
				return (SCREEN_REDRAW_BORDER);
		}
	} else {
		if ((wp->xoff == 0 || px >= wp->xoff - 1) && px <= ex) {
			if (py == ey)
				return (SCREEN_REDRAW_BORDER);
		}
	}

	/* Outside pane. */
	return (SCREEN_REDRAW_OUTSIDE);
}

/* Check if a cell is on a border. */
static int
screen_redraw_cell_border(struct client *c, u_int px, u_int py, int pane_status)
{
	struct window		*w = c->session->curw->window;
	struct window_pane	*wp;

	/* Outside the window? */
	if (px > w->sx || py > w->sy)
		return (0);

	/* On the window border? */
	if (px == w->sx || py == w->sy)
		return (1);

	/* Check all the panes. */
	TAILQ_FOREACH(wp, &w->panes, entry) {
		if (!window_pane_visible(wp))
			continue;
		switch (screen_redraw_pane_border(wp, px, py, pane_status)) {
		case SCREEN_REDRAW_INSIDE:
			return (0);
		case SCREEN_REDRAW_BORDER:
			return (1);
		case SCREEN_REDRAW_OUTSIDE:
			break;
		}
	}

	return (0);
}

/* Work out type of border cell from surrounding cells. */
static int
screen_redraw_type_of_cell(struct client *c, u_int px, u_int py,
    int pane_status)
{
	struct window	*w = c->session->curw->window;
	u_int		 sx = w->sx, sy = w->sy;
	int		 borders = 0;

	/*
	 * Construct a bitmask of whether the cells to the left (bit 4), right,
	 * top, and bottom (bit 1) of this cell are borders.
	 */
	if (px == 0 || screen_redraw_cell_border(c, px - 1, py, pane_status))
		borders |= 8;
	if (px <= sx && screen_redraw_cell_border(c, px + 1, py, pane_status))
		borders |= 4;
	if (pane_status == PANE_STATUS_TOP) {
		if (py != 0 &&
		    screen_redraw_cell_border(c, px, py - 1, pane_status))
			borders |= 2;
	} else {
		if (py == 0 ||
		    screen_redraw_cell_border(c, px, py - 1, pane_status))
		    borders |= 2;
	}
	if (py <= sy && screen_redraw_cell_border(c, px, py + 1, pane_status))
		borders |= 1;

	/*
	 * Figure out what kind of border this cell is. Only one bit set
	 * doesn't make sense (can't have a border cell with no others
	 * connected).
	 */
	switch (borders) {
	case 15:	/* 1111, left right top bottom */
		return (CELL_JOIN);
	case 14:	/* 1110, left right top */
		return (CELL_BOTTOMJOIN);
	case 13:	/* 1101, left right bottom */
		return (CELL_TOPJOIN);
	case 12:	/* 1100, left right */
		return (CELL_TOPBOTTOM);
	case 11:	/* 1011, left top bottom */
		return (CELL_RIGHTJOIN);
	case 10:	/* 1010, left top */
		return (CELL_BOTTOMRIGHT);
	case 9:		/* 1001, left bottom */
		return (CELL_TOPRIGHT);
	case 7:		/* 0111, right top bottom */
		return (CELL_LEFTJOIN);
	case 6:		/* 0110, right top */
		return (CELL_BOTTOMLEFT);
	case 5:		/* 0101, right bottom */
		return (CELL_TOPLEFT);
	case 3:		/* 0011, top bottom */
		return (CELL_LEFTRIGHT);
	}
	return (CELL_OUTSIDE);
}

/* Check if cell inside a pane. */
static int
screen_redraw_check_cell(struct client *c, u_int px, u_int py, int pane_status,
    struct window_pane **wpp)
{
	struct window		*w = c->session->curw->window;
	struct window_pane	*wp, *active;
	int			 border;
	u_int			 right, line;

	*wpp = NULL;

	if (px > w->sx || py > w->sy)
		return (CELL_OUTSIDE);
	if (px == w->sx || py == w->sy) /* window border */
		return (screen_redraw_type_of_cell(c, px, py, pane_status));

	if (pane_status != PANE_STATUS_OFF) {
		active = wp = server_client_get_pane(c);
		do {
			if (!window_pane_visible(wp))
				goto next1;

			if (pane_status == PANE_STATUS_TOP)
				line = wp->yoff - 1;
			else
				line = wp->yoff + wp->sy;
			right = wp->xoff + 2 + wp->status_size - 1;

			if (py == line && px >= wp->xoff + 2 && px <= right)
				return (CELL_INSIDE);

		next1:
			wp = TAILQ_NEXT(wp, entry);
			if (wp == NULL)
				wp = TAILQ_FIRST(&w->panes);
		} while (wp != active);
	}

	active = wp = server_client_get_pane(c);
	do {
		if (!window_pane_visible(wp))
			goto next2;
		*wpp = wp;

		/*
		 * If definitely inside, return. If not on border, skip.
		 * Otherwise work out the cell.
		 */
		border = screen_redraw_pane_border(wp, px, py, pane_status);
		if (border == SCREEN_REDRAW_INSIDE)
			return (CELL_INSIDE);
		if (border == SCREEN_REDRAW_OUTSIDE)
			goto next2;
		return (screen_redraw_type_of_cell(c, px, py, pane_status));

	next2:
		wp = TAILQ_NEXT(wp, entry);
		if (wp == NULL)
			wp = TAILQ_FIRST(&w->panes);
	} while (wp != active);

	return (CELL_OUTSIDE);
}

/* Check if the border of a particular pane. */
static int
screen_redraw_check_is(u_int px, u_int py, int pane_status,
    struct window_pane *wp)
{
	enum screen_redraw_border_type	border;

	border = screen_redraw_pane_border(wp, px, py, pane_status);
	if (border == SCREEN_REDRAW_BORDER)
		return (1);
	return (0);
}

/* Update pane status. */
static int
screen_redraw_make_pane_status(struct client *c, struct window *w,
    struct window_pane *wp)
{
	struct grid_cell	 gc;
	const char		*fmt;
	struct format_tree	*ft;
	char			*expanded;
	u_int			 width, i;
	struct screen_write_ctx	 ctx;
	struct screen		 old;

	ft = format_create(c, NULL, FORMAT_PANE|wp->id, FORMAT_STATUS);
	format_defaults(ft, c, c->session, c->session->curw, wp);

	if (wp == server_client_get_pane(c))
		style_apply(&gc, w->options, "pane-active-border-style", ft);
	else
		style_apply(&gc, w->options, "pane-border-style", ft);
	fmt = options_get_string(w->options, "pane-border-format");

	expanded = format_expand_time(ft, fmt);
	if (wp->sx < 4)
		wp->status_size = width = 0;
	else
		wp->status_size = width = wp->sx - 4;

	memcpy(&old, &wp->status_screen, sizeof old);
	screen_init(&wp->status_screen, width, 1, 0);
	wp->status_screen.mode = 0;

	screen_write_start(&ctx, &wp->status_screen);

	gc.attr |= GRID_ATTR_CHARSET;
	for (i = 0; i < width; i++)
		screen_write_putc(&ctx, &gc, 'q');
	gc.attr &= ~GRID_ATTR_CHARSET;

	screen_write_cursormove(&ctx, 0, 0, 0);
	format_draw(&ctx, &gc, width, expanded, NULL);
	screen_write_stop(&ctx);

	free(expanded);
	format_free(ft);

	if (grid_compare(wp->status_screen.grid, old.grid) == 0) {
		screen_free(&old);
		return (0);
	}
	screen_free(&old);
	return (1);
}

/* Draw pane status. */
static void
screen_redraw_draw_pane_status(struct screen_redraw_ctx *ctx)
{
	struct client		*c = ctx->c;
	struct window		*w = c->session->curw->window;
	struct tty		*tty = &c->tty;
	struct window_pane	*wp;
	struct screen		*s;
	u_int			 i, x, width, xoff, yoff, size;

	log_debug("%s: %s @%u", __func__, c->name, w->id);

	TAILQ_FOREACH(wp, &w->panes, entry) {
		if (!window_pane_visible(wp))
			continue;
		s = &wp->status_screen;

		size = wp->status_size;
		if (ctx->pane_status == PANE_STATUS_TOP)
			yoff = wp->yoff - 1;
		else
			yoff = wp->yoff + wp->sy;
		xoff = wp->xoff + 2;

		if (xoff + size <= ctx->ox ||
		    xoff >= ctx->ox + ctx->sx ||
		    yoff < ctx->oy ||
		    yoff >= ctx->oy + ctx->sy)
			continue;

		if (xoff >= ctx->ox && xoff + size <= ctx->ox + ctx->sx) {
			/* All visible. */
			i = 0;
			x = xoff - ctx->ox;
			width = size;
		} else if (xoff < ctx->ox && xoff + size > ctx->ox + ctx->sx) {
			/* Both left and right not visible. */
			i = ctx->ox;
			x = 0;
			width = ctx->sx;
		} else if (xoff < ctx->ox) {
			/* Left not visible. */
			i = ctx->ox - xoff;
			x = 0;
			width = size - i;
		} else {
			/* Right not visible. */
			i = 0;
			x = xoff - ctx->ox;
			width = size - x;
		}

		if (ctx->statustop)
			yoff += ctx->statuslines;
		tty_draw_line(tty, s, i, 0, width, x, yoff - ctx->oy,
		    &grid_default_cell, NULL);
	}
	tty_cursor(tty, 0, 0);
}

/* Update status line and change flags if unchanged. */
static int
screen_redraw_update(struct client *c, int flags)
{
	struct window		*w = c->session->curw->window;
	struct window_pane	*wp;
	struct options		*wo = w->options;
	int			 redraw;

	if (c->message_string != NULL)
		redraw = status_message_redraw(c);
	else if (c->prompt_string != NULL)
		redraw = status_prompt_redraw(c);
	else
		redraw = status_redraw(c);
	if (!redraw && (~flags & CLIENT_REDRAWSTATUSALWAYS))
		flags &= ~CLIENT_REDRAWSTATUS;

	if (c->overlay_draw != NULL)
		flags |= CLIENT_REDRAWOVERLAY;

	if (options_get_number(wo, "pane-border-status") != PANE_STATUS_OFF) {
		redraw = 0;
		TAILQ_FOREACH(wp, &w->panes, entry) {
			if (screen_redraw_make_pane_status(c, w, wp))
				redraw = 1;
		}
		if (redraw)
			flags |= CLIENT_REDRAWBORDERS;
	}
	return (flags);
}

/* Set up redraw context. */
static void
screen_redraw_set_context(struct client *c, struct screen_redraw_ctx *ctx)
{
	struct session	*s = c->session;
	struct options	*oo = s->options;
	struct window	*w = s->curw->window;
	struct options	*wo = w->options;
	u_int		 lines;

	memset(ctx, 0, sizeof *ctx);
	ctx->c = c;

	lines = status_line_size(c);
	if (c->message_string != NULL || c->prompt_string != NULL)
		lines = (lines == 0) ? 1 : lines;
	if (lines != 0 && options_get_number(oo, "status-position") == 0)
		ctx->statustop = 1;
	ctx->statuslines = lines;

	ctx->pane_status = options_get_number(wo, "pane-border-status");

	tty_window_offset(&c->tty, &ctx->ox, &ctx->oy, &ctx->sx, &ctx->sy);

	log_debug("%s: %s @%u ox=%u oy=%u sx=%u sy=%u %u/%d", __func__, c->name,
	    w->id, ctx->ox, ctx->oy, ctx->sx, ctx->sy, ctx->statuslines,
	    ctx->statustop);
}

/* Redraw entire screen. */
void
screen_redraw_screen(struct client *c)
{
	struct screen_redraw_ctx	ctx;
	int				flags;

	if (c->flags & CLIENT_SUSPENDED)
		return;

	flags = screen_redraw_update(c, c->flags);
	if ((flags & CLIENT_ALLREDRAWFLAGS) == 0)
		return;

	screen_redraw_set_context(c, &ctx);
	tty_update_mode(&c->tty, c->tty.mode, NULL);
	tty_sync_start(&c->tty);

	if (flags & (CLIENT_REDRAWWINDOW|CLIENT_REDRAWBORDERS)) {
		log_debug("%s: redrawing borders", c->name);
		if (ctx.pane_status != PANE_STATUS_OFF)
			screen_redraw_draw_pane_status(&ctx);
		screen_redraw_draw_borders(&ctx);
	}
	if (flags & CLIENT_REDRAWWINDOW) {
		log_debug("%s: redrawing panes", c->name);
		screen_redraw_draw_panes(&ctx);
	}
	if (ctx.statuslines != 0 &&
	    (flags & (CLIENT_REDRAWSTATUS|CLIENT_REDRAWSTATUSALWAYS))) {
		log_debug("%s: redrawing status", c->name);
		screen_redraw_draw_status(&ctx);
	}
	if (c->overlay_draw != NULL && (flags & CLIENT_REDRAWOVERLAY)) {
		log_debug("%s: redrawing overlay", c->name);
		c->overlay_draw(c, &ctx);
	}

	tty_reset(&c->tty);
}

/* Redraw a single pane. */
void
screen_redraw_pane(struct client *c, struct window_pane *wp)
{
	struct screen_redraw_ctx	 ctx;

	if (c->overlay_draw != NULL || !window_pane_visible(wp))
		return;

	screen_redraw_set_context(c, &ctx);
	tty_update_mode(&c->tty, c->tty.mode, NULL);
	tty_sync_start(&c->tty);

	screen_redraw_draw_pane(&ctx, wp);

	tty_reset(&c->tty);
}

/* Get border cell style. */
static const struct grid_cell *
screen_redraw_draw_borders_style(struct screen_redraw_ctx *ctx, u_int x,
    u_int y, struct window_pane *wp)
{
	struct client		*c = ctx->c;
	struct session		*s = c->session;
	struct window		*w = s->curw->window;
	struct window_pane	*active = server_client_get_pane(c);
	struct options		*oo = w->options;
	struct grid_cell	*gc;
	struct format_tree	*ft;

	if (wp->border_gc_set)
		return (&wp->border_gc);
	wp->border_gc_set = 1;

	ft = format_create_defaults(NULL, c, s, s->curw, wp);
	gc = &wp->border_gc;

	if (screen_redraw_check_is(x, y, ctx->pane_status, active)) {
		style_apply(gc, oo, "pane-active-border-style", ft);
		gc->attr |= GRID_ATTR_CHARSET;
	} else {
		style_apply(gc, oo, "pane-border-style", ft);
		gc->attr |= GRID_ATTR_CHARSET;
	}

	format_free(ft);
	return (gc);
}

/* Draw a border cell. */
static void
screen_redraw_draw_borders_cell(struct screen_redraw_ctx *ctx, u_int i, u_int j)
{
	struct client		*c = ctx->c;
	struct session		*s = c->session;
	struct tty		*tty = &c->tty;
	struct window_pane	*wp;
	u_int			 type, x = ctx->ox + i, y = ctx->oy + j;
	int			 pane_status = ctx->pane_status;
	const struct grid_cell	*gc;
	struct grid_cell	 copy;

	if (c->overlay_check != NULL && !c->overlay_check(c, x, y))
		return;

	type = screen_redraw_check_cell(c, x, y, pane_status, &wp);
	if (type == CELL_INSIDE)
		return;

	if (wp == NULL)
		gc = &screen_redraw_border_cell;
	else {
		gc = screen_redraw_draw_borders_style(ctx, x, y, wp);
		if (gc == NULL)
			return;

		if (server_is_marked(s, s->curw, marked_pane.wp) &&
		    screen_redraw_check_is(x, y, pane_status, marked_pane.wp)) {
			memcpy(&copy, gc, sizeof copy);
			copy.attr ^= GRID_ATTR_REVERSE;
			gc = &copy;
		}
	}

	tty_attributes(tty, gc, &grid_default_cell, NULL);
	if (ctx->statustop)
		tty_cursor(tty, i, ctx->statuslines + j);
	else
		tty_cursor(tty, i, j);
	tty_putc(tty, CELL_BORDERS[type]);
}

/* Draw the borders. */
static void
screen_redraw_draw_borders(struct screen_redraw_ctx *ctx)
{
	struct client		*c = ctx->c;
	struct session		*s = c->session;
	struct window		*w = s->curw->window;
	struct window_pane	*wp;
	u_int		 	 i, j;

	log_debug("%s: %s @%u", __func__, c->name, w->id);

	TAILQ_FOREACH(wp, &w->panes, entry)
		wp->border_gc_set = 0;

	for (j = 0; j < c->tty.sy - ctx->statuslines; j++) {
		for (i = 0; i < c->tty.sx; i++)
			screen_redraw_draw_borders_cell(ctx, i, j);
	}
}

/* Draw the panes. */
static void
screen_redraw_draw_panes(struct screen_redraw_ctx *ctx)
{
	struct client		*c = ctx->c;
	struct window		*w = c->session->curw->window;
	struct window_pane	*wp;

	log_debug("%s: %s @%u", __func__, c->name, w->id);

	TAILQ_FOREACH(wp, &w->panes, entry) {
		if (window_pane_visible(wp))
			screen_redraw_draw_pane(ctx, wp);
	}
}

/* Draw the status line. */
static void
screen_redraw_draw_status(struct screen_redraw_ctx *ctx)
{
	struct client	*c = ctx->c;
	struct window	*w = c->session->curw->window;
	struct tty	*tty = &c->tty;
	struct screen	*s = c->status.active;
	u_int		 i, y;

	log_debug("%s: %s @%u", __func__, c->name, w->id);

	if (ctx->statustop)
		y = 0;
	else
		y = c->tty.sy - ctx->statuslines;
	for (i = 0; i < ctx->statuslines; i++) {
		tty_draw_line(tty, s, 0, i, UINT_MAX, 0, y + i,
		    &grid_default_cell, NULL);
	}
}

/* Draw one pane. */
static void
screen_redraw_draw_pane(struct screen_redraw_ctx *ctx, struct window_pane *wp)
{
	struct client	*c = ctx->c;
	struct window	*w = c->session->curw->window;
	struct tty	*tty = &c->tty;
	struct screen	*s;
	struct grid_cell defaults;
	u_int		 i, j, top, x, y, width;

	log_debug("%s: %s @%u %%%u", __func__, c->name, w->id, wp->id);

	if (wp->xoff + wp->sx <= ctx->ox || wp->xoff >= ctx->ox + ctx->sx)
		return;
	if (ctx->statustop)
		top = ctx->statuslines;
	else
		top = 0;

	s = wp->screen;
	for (j = 0; j < wp->sy; j++) {
		if (wp->yoff + j < ctx->oy || wp->yoff + j >= ctx->oy + ctx->sy)
			continue;
		y = top + wp->yoff + j - ctx->oy;

		if (wp->xoff >= ctx->ox &&
		    wp->xoff + wp->sx <= ctx->ox + ctx->sx) {
			/* All visible. */
			i = 0;
			x = wp->xoff - ctx->ox;
			width = wp->sx;
		} else if (wp->xoff < ctx->ox &&
		    wp->xoff + wp->sx > ctx->ox + ctx->sx) {
			/* Both left and right not visible. */
			i = ctx->ox;
			x = 0;
			width = ctx->sx;
		} else if (wp->xoff < ctx->ox) {
			/* Left not visible. */
			i = ctx->ox - wp->xoff;
			x = 0;
			width = wp->sx - i;
		} else {
			/* Right not visible. */
			i = 0;
			x = wp->xoff - ctx->ox;
			width = ctx->sx - x;
		}
		log_debug("%s: %s %%%u line %u,%u at %u,%u, width %u",
		    __func__, c->name, wp->id, i, j, x, y, width);

		tty_default_colours(&defaults, wp);
		tty_draw_line(tty, s, i, j, width, x, y, &defaults,
		    wp->palette);
	}
}