screen.c - tmux - Rivoreo Source Code Repositories

 /* $OpenBSD$ */

 /*
  * 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 <unistd.h>
 #include <vis.h>

 #include "tmux.h"

 /* Selected area in screen. */
 struct screen_sel {
 	int		 hidden;
 	int		 rectangle;
 	int		 modekeys;

 	u_int		 sx;
 	u_int		 sy;

 	u_int		 ex;
 	u_int		 ey;

 	struct grid_cell cell;
 };

 /* Entry on title stack. */
 struct screen_title_entry {
 	char				*text;

 	TAILQ_ENTRY(screen_title_entry)	 entry;
 };
 TAILQ_HEAD(screen_titles, screen_title_entry);

 static void	screen_resize_y(struct screen *, u_int, int, u_int *);
 static void	screen_reflow(struct screen *, u_int, u_int *, u_int *, int);

 /* Free titles stack. */
 static void
 screen_free_titles(struct screen *s)
 {
 	struct screen_title_entry	*title_entry;

 	if (s->titles == NULL)
 		return;

 	while ((title_entry = TAILQ_FIRST(s->titles)) != NULL) {
 		TAILQ_REMOVE(s->titles, title_entry, entry);
 		free(title_entry->text);
 		free(title_entry);
 	}

 	free(s->titles);
 	s->titles = NULL;
 }

 /* Create a new screen. */
 void
 screen_init(struct screen *s, u_int sx, u_int sy, u_int hlimit)
 {
 	s->grid = grid_create(sx, sy, hlimit);
 	s->saved_grid = NULL;

 	s->title = xstrdup("");
 	s->titles = NULL;
 	s->path = NULL;

 	s->cstyle = SCREEN_CURSOR_DEFAULT;
 	s->ccolour = xstrdup("");
 	s->tabs = NULL;
 	s->sel = NULL;

 	s->write_list = NULL;

 	screen_reinit(s);
 }

 /* Reinitialise screen. */
 void
 screen_reinit(struct screen *s)
 {
 	s->cx = 0;
 	s->cy = 0;

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

 	s->mode = MODE_CURSOR|MODE_WRAP;
 	if (options_get_number(global_options, "extended-keys") == 2)
 		s->mode |= MODE_KEXTENDED;

 	if (s->saved_grid != NULL)
 		screen_alternate_off(s, NULL, 0);
 	s->saved_cx = UINT_MAX;
 	s->saved_cy = UINT_MAX;

 	screen_reset_tabs(s);

 	grid_clear_lines(s->grid, s->grid->hsize, s->grid->sy, 8);

 	screen_clear_selection(s);
 	screen_free_titles(s);
 }

 /* Destroy a screen. */
 void
 screen_free(struct screen *s)
 {
 	free(s->sel);
 	free(s->tabs);
 	free(s->path);
 	free(s->title);
 	free(s->ccolour);

 	if (s->write_list != NULL)
 		screen_write_free_list(s);

 	if (s->saved_grid != NULL)
 		grid_destroy(s->saved_grid);
 	grid_destroy(s->grid);

 	screen_free_titles(s);
 }

 /* Reset tabs to default, eight spaces apart. */
 void
 screen_reset_tabs(struct screen *s)
 {
 	u_int	i;

 	free(s->tabs);

 	if ((s->tabs = bit_alloc(screen_size_x(s))) == NULL)
 		fatal("bit_alloc failed");
 	for (i = 8; i < screen_size_x(s); i += 8)
 		bit_set(s->tabs, i);
 }

 /* Set screen cursor style. */
 void
 screen_set_cursor_style(struct screen *s, u_int style)
 {
 	log_debug("%s: new %u, was %u", __func__, style, s->cstyle);
 	switch (style) {
 	case 0:
 		s->cstyle = SCREEN_CURSOR_DEFAULT;
 		break;
 	case 1:
 		s->cstyle = SCREEN_CURSOR_BLOCK;
 		s->mode |= MODE_BLINKING;
 		break;
 	case 2:
 		s->cstyle = SCREEN_CURSOR_BLOCK;
 		s->mode &= ~MODE_BLINKING;
 		break;
 	case 3:
 		s->cstyle = SCREEN_CURSOR_UNDERLINE;
 		s->mode |= MODE_BLINKING;
 		break;
 	case 4:
 		s->cstyle = SCREEN_CURSOR_UNDERLINE;
 		s->mode &= ~MODE_BLINKING;
 		break;
 	case 5:
 		s->cstyle = SCREEN_CURSOR_BAR;
 		s->mode |= MODE_BLINKING;
 		break;
 	case 6:
 		s->cstyle = SCREEN_CURSOR_BAR;
 		s->mode &= ~MODE_BLINKING;
 		break;
 	}
 }

 /* Set screen cursor colour. */
 void
 screen_set_cursor_colour(struct screen *s, const char *colour)
 {
 	free(s->ccolour);
 	s->ccolour = xstrdup(colour);
 }

 /* Set screen title. */
 int
 screen_set_title(struct screen *s, const char *title)
 {
 	if (!utf8_isvalid(title))
 		return (0);
 	free(s->title);
 	s->title = xstrdup(title);
 	return (1);
 }

 /* Set screen path. */
 void
 screen_set_path(struct screen *s, const char *path)
 {
 	free(s->path);
 	utf8_stravis(&s->path, path, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);
 }

 /* Push the current title onto the stack. */
 void
 screen_push_title(struct screen *s)
 {
 	struct screen_title_entry *title_entry;

 	if (s->titles == NULL) {
 		s->titles = xmalloc(sizeof *s->titles);
 		TAILQ_INIT(s->titles);
 	}
 	title_entry = xmalloc(sizeof *title_entry);
 	title_entry->text = xstrdup(s->title);
 	TAILQ_INSERT_HEAD(s->titles, title_entry, entry);
 }

 /*
  * Pop a title from the stack and set it as the screen title. If the stack is
  * empty, do nothing.
  */
 void
 screen_pop_title(struct screen *s)
 {
 	struct screen_title_entry *title_entry;

 	if (s->titles == NULL)
 		return;

 	title_entry = TAILQ_FIRST(s->titles);
 	if (title_entry != NULL) {
 		screen_set_title(s, title_entry->text);

 		TAILQ_REMOVE(s->titles, title_entry, entry);
 		free(title_entry->text);
 		free(title_entry);
 	}
 }

 /* Resize screen with options. */
 void
 screen_resize_cursor(struct screen *s, u_int sx, u_int sy, int reflow,
     int eat_empty, int cursor)
 {
 	u_int	cx = s->cx, cy = s->grid->hsize + s->cy;

 	if (s->write_list != NULL)
 		screen_write_free_list(s);

 	log_debug("%s: new size %ux%u, now %ux%u (cursor %u,%u = %u,%u)",
 	    __func__, sx, sy, screen_size_x(s), screen_size_y(s), s->cx, s->cy,
 	    cx, cy);

 	if (sx < 1)
 		sx = 1;
 	if (sy < 1)
 		sy = 1;

 	if (sx != screen_size_x(s)) {
 		s->grid->sx = sx;
 		screen_reset_tabs(s);
 	} else
 		reflow = 0;

 	if (sy != screen_size_y(s))
 		screen_resize_y(s, sy, eat_empty, &cy);

 	if (reflow)
 		screen_reflow(s, sx, &cx, &cy, cursor);

 	if (cy >= s->grid->hsize) {
 		s->cx = cx;
 		s->cy = cy - s->grid->hsize;
 	} else {
 		s->cx = 0;
 		s->cy = 0;
 	}

 	log_debug("%s: cursor finished at %u,%u = %u,%u", __func__, s->cx,
 	    s->cy, cx, cy);

 	if (s->write_list != NULL)
 		screen_write_make_list(s);
 }

 /* Resize screen. */
 void
 screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)
 {
 	screen_resize_cursor(s, sx, sy, reflow, 1, 1);
 }

 static void
 screen_resize_y(struct screen *s, u_int sy, int eat_empty, u_int *cy)
 {
 	struct grid	*gd = s->grid;
 	u_int		 needed, available, oldy, i;

 	if (sy == 0)
 		fatalx("zero size");
 	oldy = screen_size_y(s);

 	/*
 	 * When resizing:
 	 *
 	 * If the height is decreasing, delete lines from the bottom until
 	 * hitting the cursor, then push lines from the top into the history.
 	 *
 	 * When increasing, pull as many lines as possible from scrolled
 	 * history (not explicitly cleared from view) to the top, then fill the
 	 * remaining with blanks at the bottom.
 	 */

 	/* Size decreasing. */
 	if (sy < oldy) {
 		needed = oldy - sy;

 		/* Delete as many lines as possible from the bottom. */
 		if (eat_empty) {
 			available = oldy - 1 - s->cy;
 			if (available > 0) {
 				if (available > needed)
 					available = needed;
 				grid_view_delete_lines(gd, oldy - available,
 				    available, 8);
 			}
 			needed -= available;
 		}

 		/*
 		 * Now just increase the history size, if possible, to take
 		 * over the lines which are left. If history is off, delete
 		 * lines from the top.
 		 */
 		available = s->cy;
 		if (gd->flags & GRID_HISTORY) {
 			gd->hscrolled += needed;
 			gd->hsize += needed;
 		} else if (needed > 0 && available > 0) {
 			if (available > needed)
 				available = needed;
 			grid_view_delete_lines(gd, 0, available, 8);
 			(*cy) -= available;
 		}
 	}

 	/* Resize line array. */
 	grid_adjust_lines(gd, gd->hsize + sy);

 	/* Size increasing. */
 	if (sy > oldy) {
 		needed = sy - oldy;

 		/*
 		 * Try to pull as much as possible out of scrolled history, if
 		 * is is enabled.
 		 */
 		available = gd->hscrolled;
 		if (gd->flags & GRID_HISTORY && available > 0) {
 			if (available > needed)
 				available = needed;
 			gd->hscrolled -= available;
 			gd->hsize -= available;
 		} else
 			available = 0;
 		needed -= available;

 		/* Then fill the rest in with blanks. */
 		for (i = gd->hsize + sy - needed; i < gd->hsize + sy; i++)
 			grid_empty_line(gd, i, 8);
 	}

 	/* Set the new size, and reset the scroll region. */
 	gd->sy = sy;
 	s->rupper = 0;
 	s->rlower = screen_size_y(s) - 1;
 }

 /* Set selection. */
 void
 screen_set_selection(struct screen *s, u_int sx, u_int sy,
     u_int ex, u_int ey, u_int rectangle, int modekeys, struct grid_cell *gc)
 {
 	if (s->sel == NULL)
 		s->sel = xcalloc(1, sizeof *s->sel);

 	memcpy(&s->sel->cell, gc, sizeof s->sel->cell);
 	s->sel->hidden = 0;
 	s->sel->rectangle = rectangle;
 	s->sel->modekeys = modekeys;

 	s->sel->sx = sx;
 	s->sel->sy = sy;
 	s->sel->ex = ex;
 	s->sel->ey = ey;
 }

 /* Clear selection. */
 void
 screen_clear_selection(struct screen *s)
 {
 	free(s->sel);
 	s->sel = NULL;
 }

 /* Hide selection. */
 void
 screen_hide_selection(struct screen *s)
 {
 	if (s->sel != NULL)
 		s->sel->hidden = 1;
 }

 /* Check if cell in selection. */
 int
 screen_check_selection(struct screen *s, u_int px, u_int py)
 {
 	struct screen_sel	*sel = s->sel;
 	u_int			 xx;

 	if (sel == NULL || sel->hidden)
 		return (0);

 	if (sel->rectangle) {
 		if (sel->sy < sel->ey) {
 			/* start line < end line -- downward selection. */
 			if (py < sel->sy || py > sel->ey)
 				return (0);
 		} else if (sel->sy > sel->ey) {
 			/* start line > end line -- upward selection. */
 			if (py > sel->sy || py < sel->ey)
 				return (0);
 		} else {
 			/* starting line == ending line. */
 			if (py != sel->sy)
 				return (0);
 		}

 		/*
 		 * Need to include the selection start row, but not the cursor
 		 * row, which means the selection changes depending on which
 		 * one is on the left.
 		 */
 		if (sel->ex < sel->sx) {
 			/* Cursor (ex) is on the left. */
 			if (px < sel->ex)
 				return (0);

 			if (px > sel->sx)
 				return (0);
 		} else {
 			/* Selection start (sx) is on the left. */
 			if (px < sel->sx)
 				return (0);

 			if (px > sel->ex)
 				return (0);
 		}
 	} else {
 		/*
 		 * Like emacs, keep the top-left-most character, and drop the
 		 * bottom-right-most, regardless of copy direction.
 		 */
 		if (sel->sy < sel->ey) {
 			/* starting line < ending line -- downward selection. */
 			if (py < sel->sy || py > sel->ey)
 				return (0);

 			if (py == sel->sy && px < sel->sx)
 				return (0);

 			if (sel->modekeys == MODEKEY_EMACS)
 				xx = (sel->ex == 0 ? 0 : sel->ex - 1);
 			else
 				xx = sel->ex;
 			if (py == sel->ey && px > xx)
 				return (0);
 		} else if (sel->sy > sel->ey) {
 			/* starting line > ending line -- upward selection. */
 			if (py > sel->sy || py < sel->ey)
 				return (0);

 			if (py == sel->ey && px < sel->ex)
 				return (0);

 			if (sel->modekeys == MODEKEY_EMACS)
 				xx = sel->sx - 1;
 			else
 				xx = sel->sx;
 			if (py == sel->sy && (sel->sx == 0 || px > xx))
 				return (0);
 		} else {
 			/* starting line == ending line. */
 			if (py != sel->sy)
 				return (0);

 			if (sel->ex < sel->sx) {
 				/* cursor (ex) is on the left */
 				if (sel->modekeys == MODEKEY_EMACS)
 					xx = sel->sx - 1;
 				else
 					xx = sel->sx;
 				if (px > xx || px < sel->ex)
 					return (0);
 			} else {
 				/* selection start (sx) is on the left */
 				if (sel->modekeys == MODEKEY_EMACS)
 					xx = (sel->ex == 0 ? 0 : sel->ex - 1);
 				else
 					xx = sel->ex;
 				if (px < sel->sx || px > xx)
 					return (0);
 			}
 		}
 	}

 	return (1);
 }

 /* Get selected grid cell. */
 void
 screen_select_cell(struct screen *s, struct grid_cell *dst,
     const struct grid_cell *src)
 {
 	if (s->sel == NULL || s->sel->hidden)
 		return;

 	memcpy(dst, &s->sel->cell, sizeof *dst);

 	utf8_copy(&dst->data, &src->data);
 	dst->attr = dst->attr & ~GRID_ATTR_CHARSET;
 	dst->attr |= src->attr & GRID_ATTR_CHARSET;
 	dst->flags = src->flags;
 }

 /* Reflow wrapped lines. */
 static void
 screen_reflow(struct screen *s, u_int new_x, u_int *cx, u_int *cy, int cursor)
 {
 	u_int	wx, wy;

 	if (cursor) {
 		grid_wrap_position(s->grid, *cx, *cy, &wx, &wy);
 		log_debug("%s: cursor %u,%u is %u,%u", __func__, *cx, *cy, wx,
 		    wy);
 	}

 	grid_reflow(s->grid, new_x);

 	if (cursor) {
 		grid_unwrap_position(s->grid, cx, cy, wx, wy);
 		log_debug("%s: new cursor is %u,%u", __func__, *cx, *cy);
 	}
 	else {
 		*cx = 0;
 		*cy = s->grid->hsize;
 	}
 }

 /*
  * Enter alternative screen mode. A copy of the visible screen is saved and the
  * history is not updated.
  */
 void
 screen_alternate_on(struct screen *s, struct grid_cell *gc, int cursor)
 {
 	u_int	sx, sy;

 	if (s->saved_grid != NULL)
 		return;
 	sx = screen_size_x(s);
 	sy = screen_size_y(s);

 	s->saved_grid = grid_create(sx, sy, 0);
 	grid_duplicate_lines(s->saved_grid, 0, s->grid, screen_hsize(s), sy);
 	if (cursor) {
 		s->saved_cx = s->cx;
 		s->saved_cy = s->cy;
 	}
 	memcpy(&s->saved_cell, gc, sizeof s->saved_cell);

 	grid_view_clear(s->grid, 0, 0, sx, sy, 8);

 	s->saved_flags = s->grid->flags;
 	s->grid->flags &= ~GRID_HISTORY;
 }

 /* Exit alternate screen mode and restore the copied grid. */
 void
 screen_alternate_off(struct screen *s, struct grid_cell *gc, int cursor)
 {
 	u_int	sx = screen_size_x(s), sy = screen_size_y(s);

 	/*
 	 * If the current size is different, temporarily resize to the old size
 	 * before copying back.
 	 */
 	if (s->saved_grid != NULL)
 		screen_resize(s, s->saved_grid->sx, s->saved_grid->sy, 1);

 	/*
 	 * Restore the cursor position and cell. This happens even if not
 	 * currently in the alternate screen.
 	 */
 	if (cursor && s->saved_cx != UINT_MAX && s->saved_cy != UINT_MAX) {
 		s->cx = s->saved_cx;
 		s->cy = s->saved_cy;
 		if (gc != NULL)
 			memcpy(gc, &s->saved_cell, sizeof *gc);
 	}

 	/* If not in the alternate screen, do nothing more. */
 	if (s->saved_grid == NULL) {
 		if (s->cx > screen_size_x(s) - 1)
 			s->cx = screen_size_x(s) - 1;
 		if (s->cy > screen_size_y(s) - 1)
 			s->cy = screen_size_y(s) - 1;
 		return;
 	}

 	/* Restore the saved grid. */
 	grid_duplicate_lines(s->grid, screen_hsize(s), s->saved_grid, 0,
 	    s->saved_grid->sy);

 	/*
 	 * Turn history back on (so resize can use it) and then resize back to
 	 * the current size.
 	 */
 	if (s->saved_flags & GRID_HISTORY)
 		s->grid->flags |= GRID_HISTORY;
 	screen_resize(s, sx, sy, 1);

 	grid_destroy(s->saved_grid);
 	s->saved_grid = NULL;

 	if (s->cx > screen_size_x(s) - 1)
 		s->cx = screen_size_x(s) - 1;
 	if (s->cy > screen_size_y(s) - 1)
 		s->cy = screen_size_y(s) - 1;
 }

 /* Get mode as a string. */
 const char *
 screen_mode_to_string(int mode)
 {
 	static char	tmp[1024];

 	if (mode == 0)
 		return "NONE";
 	if (mode == ALL_MODES)
 		return "ALL";

 	*tmp = '\0';
 	if (mode & MODE_CURSOR)
 		strlcat(tmp, "CURSOR,", sizeof tmp);
 	if (mode & MODE_INSERT)
 		strlcat(tmp, "INSERT,", sizeof tmp);
 	if (mode & MODE_KCURSOR)
 		strlcat(tmp, "KCURSOR,", sizeof tmp);
 	if (mode & MODE_KKEYPAD)
 		strlcat(tmp, "KKEYPAD,", sizeof tmp);
 	if (mode & MODE_WRAP)
 		strlcat(tmp, "WRAP,", sizeof tmp);
 	if (mode & MODE_MOUSE_STANDARD)
 		strlcat(tmp, "STANDARD,", sizeof tmp);
 	if (mode & MODE_MOUSE_BUTTON)
 		strlcat(tmp, "BUTTON,", sizeof tmp);
 	if (mode & MODE_BLINKING)
 		strlcat(tmp, "BLINKING,", sizeof tmp);
 	if (mode & MODE_MOUSE_UTF8)
 		strlcat(tmp, "UTF8,", sizeof tmp);
 	if (mode & MODE_MOUSE_SGR)
 		strlcat(tmp, "SGR,", sizeof tmp);
 	if (mode & MODE_BRACKETPASTE)
 		strlcat(tmp, "BRACKETPASTE,", sizeof tmp);
 	if (mode & MODE_FOCUSON)
 		strlcat(tmp, "FOCUSON,", sizeof tmp);
 	if (mode & MODE_MOUSE_ALL)
 		strlcat(tmp, "ALL,", sizeof tmp);
 	if (mode & MODE_ORIGIN)
 		strlcat(tmp, "ORIGIN,", sizeof tmp);
 	if (mode & MODE_CRLF)
 		strlcat(tmp, "CRLF,", sizeof tmp);
 	if (mode & MODE_KEXTENDED)
 		strlcat(tmp, "KEXTENDED,", sizeof tmp);
 	tmp[strlen (tmp) - 1] = '\0';
 	return (tmp);
 }
	/* $OpenBSD$ */

	/*
	* 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 <unistd.h>
	#include <vis.h>

	#include "tmux.h"

	/* Selected area in screen. */
	struct screen_sel {
	int hidden;
	int rectangle;
	int modekeys;

	u_int sx;
	u_int sy;

	u_int ex;
	u_int ey;

	struct grid_cell cell;
	};

	/* Entry on title stack. */
	struct screen_title_entry {
	char *text;

	TAILQ_ENTRY(screen_title_entry) entry;
	};
	TAILQ_HEAD(screen_titles, screen_title_entry);

	static void screen_resize_y(struct screen , u_int, int, u_int );
	static void screen_reflow(struct screen , u_int, u_int , u_int *, int);

	/* Free titles stack. */
	static void
	screen_free_titles(struct screen *s)
	{
	struct screen_title_entry *title_entry;

	if (s->titles == NULL)
	return;

	while ((title_entry = TAILQ_FIRST(s->titles)) != NULL) {
	TAILQ_REMOVE(s->titles, title_entry, entry);
	free(title_entry->text);
	free(title_entry);
	}

	free(s->titles);
	s->titles = NULL;
	}

	/* Create a new screen. */
	void
	screen_init(struct screen *s, u_int sx, u_int sy, u_int hlimit)
	{
	s->grid = grid_create(sx, sy, hlimit);
	s->saved_grid = NULL;

	s->title = xstrdup("");
	s->titles = NULL;
	s->path = NULL;

	s->cstyle = SCREEN_CURSOR_DEFAULT;
	s->ccolour = xstrdup("");
	s->tabs = NULL;
	s->sel = NULL;

	s->write_list = NULL;

	screen_reinit(s);
	}

	/* Reinitialise screen. */
	void
	screen_reinit(struct screen *s)
	{
	s->cx = 0;
	s->cy = 0;

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

	s->mode = MODE_CURSOR\|MODE_WRAP;
	if (options_get_number(global_options, "extended-keys") == 2)
	s->mode \|= MODE_KEXTENDED;

	if (s->saved_grid != NULL)
	screen_alternate_off(s, NULL, 0);
	s->saved_cx = UINT_MAX;
	s->saved_cy = UINT_MAX;

	screen_reset_tabs(s);

	grid_clear_lines(s->grid, s->grid->hsize, s->grid->sy, 8);

	screen_clear_selection(s);
	screen_free_titles(s);
	}

	/* Destroy a screen. */
	void
	screen_free(struct screen *s)
	{
	free(s->sel);
	free(s->tabs);
	free(s->path);
	free(s->title);
	free(s->ccolour);

	if (s->write_list != NULL)
	screen_write_free_list(s);

	if (s->saved_grid != NULL)
	grid_destroy(s->saved_grid);
	grid_destroy(s->grid);

	screen_free_titles(s);
	}

	/* Reset tabs to default, eight spaces apart. */
	void
	screen_reset_tabs(struct screen *s)
	{
	u_int i;

	free(s->tabs);

	if ((s->tabs = bit_alloc(screen_size_x(s))) == NULL)
	fatal("bit_alloc failed");
	for (i = 8; i < screen_size_x(s); i += 8)
	bit_set(s->tabs, i);
	}

	/* Set screen cursor style. */
	void
	screen_set_cursor_style(struct screen *s, u_int style)
	{
	log_debug("%s: new %u, was %u", __func__, style, s->cstyle);
	switch (style) {
	case 0:
	s->cstyle = SCREEN_CURSOR_DEFAULT;
	break;
	case 1:
	s->cstyle = SCREEN_CURSOR_BLOCK;
	s->mode \|= MODE_BLINKING;
	break;
	case 2:
	s->cstyle = SCREEN_CURSOR_BLOCK;
	s->mode &= ~MODE_BLINKING;
	break;
	case 3:
	s->cstyle = SCREEN_CURSOR_UNDERLINE;
	s->mode \|= MODE_BLINKING;
	break;
	case 4:
	s->cstyle = SCREEN_CURSOR_UNDERLINE;
	s->mode &= ~MODE_BLINKING;
	break;
	case 5:
	s->cstyle = SCREEN_CURSOR_BAR;
	s->mode \|= MODE_BLINKING;
	break;
	case 6:
	s->cstyle = SCREEN_CURSOR_BAR;
	s->mode &= ~MODE_BLINKING;
	break;
	}
	}

	/* Set screen cursor colour. */
	void
	screen_set_cursor_colour(struct screen s, const char colour)
	{
	free(s->ccolour);
	s->ccolour = xstrdup(colour);
	}

	/* Set screen title. */
	int
	screen_set_title(struct screen s, const char title)
	{
	if (!utf8_isvalid(title))
	return (0);
	free(s->title);
	s->title = xstrdup(title);
	return (1);
	}

	/* Set screen path. */
	void
	screen_set_path(struct screen s, const char path)
	{
	free(s->path);
	utf8_stravis(&s->path, path, VIS_OCTAL\|VIS_CSTYLE\|VIS_TAB\|VIS_NL);
	}

	/* Push the current title onto the stack. */
	void
	screen_push_title(struct screen *s)
	{
	struct screen_title_entry *title_entry;

	if (s->titles == NULL) {
	s->titles = xmalloc(sizeof *s->titles);
	TAILQ_INIT(s->titles);
	}
	title_entry = xmalloc(sizeof *title_entry);
	title_entry->text = xstrdup(s->title);
	TAILQ_INSERT_HEAD(s->titles, title_entry, entry);
	}

	/*
	* Pop a title from the stack and set it as the screen title. If the stack is
	* empty, do nothing.
	*/
	void
	screen_pop_title(struct screen *s)
	{
	struct screen_title_entry *title_entry;

	if (s->titles == NULL)
	return;

	title_entry = TAILQ_FIRST(s->titles);
	if (title_entry != NULL) {
	screen_set_title(s, title_entry->text);

	TAILQ_REMOVE(s->titles, title_entry, entry);
	free(title_entry->text);
	free(title_entry);
	}
	}

	/* Resize screen with options. */
	void
	screen_resize_cursor(struct screen *s, u_int sx, u_int sy, int reflow,
	int eat_empty, int cursor)
	{
	u_int cx = s->cx, cy = s->grid->hsize + s->cy;

	if (s->write_list != NULL)
	screen_write_free_list(s);

	log_debug("%s: new size %ux%u, now %ux%u (cursor %u,%u = %u,%u)",
	__func__, sx, sy, screen_size_x(s), screen_size_y(s), s->cx, s->cy,
	cx, cy);

	if (sx < 1)
	sx = 1;
	if (sy < 1)
	sy = 1;

	if (sx != screen_size_x(s)) {
	s->grid->sx = sx;
	screen_reset_tabs(s);
	} else
	reflow = 0;

	if (sy != screen_size_y(s))
	screen_resize_y(s, sy, eat_empty, &cy);

	if (reflow)
	screen_reflow(s, sx, &cx, &cy, cursor);

	if (cy >= s->grid->hsize) {
	s->cx = cx;
	s->cy = cy - s->grid->hsize;
	} else {
	s->cx = 0;
	s->cy = 0;
	}

	log_debug("%s: cursor finished at %u,%u = %u,%u", __func__, s->cx,
	s->cy, cx, cy);

	if (s->write_list != NULL)
	screen_write_make_list(s);
	}

	/* Resize screen. */
	void
	screen_resize(struct screen *s, u_int sx, u_int sy, int reflow)
	{
	screen_resize_cursor(s, sx, sy, reflow, 1, 1);
	}

	static void
	screen_resize_y(struct screen s, u_int sy, int eat_empty, u_int cy)
	{
	struct grid *gd = s->grid;
	u_int needed, available, oldy, i;

	if (sy == 0)
	fatalx("zero size");
	oldy = screen_size_y(s);

	/*
	* When resizing:
	*
	* If the height is decreasing, delete lines from the bottom until
	* hitting the cursor, then push lines from the top into the history.
	*
	* When increasing, pull as many lines as possible from scrolled
	* history (not explicitly cleared from view) to the top, then fill the
	* remaining with blanks at the bottom.
	*/

	/* Size decreasing. */
	if (sy < oldy) {
	needed = oldy - sy;

	/* Delete as many lines as possible from the bottom. */
	if (eat_empty) {
	available = oldy - 1 - s->cy;
	if (available > 0) {
	if (available > needed)
	available = needed;
	grid_view_delete_lines(gd, oldy - available,
	available, 8);
	}
	needed -= available;
	}

	/*
	* Now just increase the history size, if possible, to take
	* over the lines which are left. If history is off, delete
	* lines from the top.
	*/
	available = s->cy;
	if (gd->flags & GRID_HISTORY) {
	gd->hscrolled += needed;
	gd->hsize += needed;
	} else if (needed > 0 && available > 0) {
	if (available > needed)
	available = needed;
	grid_view_delete_lines(gd, 0, available, 8);
	(*cy) -= available;
	}
	}

	/* Resize line array. */
	grid_adjust_lines(gd, gd->hsize + sy);

	/* Size increasing. */
	if (sy > oldy) {
	needed = sy - oldy;

	/*
	* Try to pull as much as possible out of scrolled history, if
	* is is enabled.
	*/
	available = gd->hscrolled;
	if (gd->flags & GRID_HISTORY && available > 0) {
	if (available > needed)
	available = needed;
	gd->hscrolled -= available;
	gd->hsize -= available;
	} else
	available = 0;
	needed -= available;

	/* Then fill the rest in with blanks. */
	for (i = gd->hsize + sy - needed; i < gd->hsize + sy; i++)
	grid_empty_line(gd, i, 8);
	}

	/* Set the new size, and reset the scroll region. */
	gd->sy = sy;
	s->rupper = 0;
	s->rlower = screen_size_y(s) - 1;
	}

	/* Set selection. */
	void
	screen_set_selection(struct screen *s, u_int sx, u_int sy,
	u_int ex, u_int ey, u_int rectangle, int modekeys, struct grid_cell *gc)
	{
	if (s->sel == NULL)
	s->sel = xcalloc(1, sizeof *s->sel);

	memcpy(&s->sel->cell, gc, sizeof s->sel->cell);
	s->sel->hidden = 0;
	s->sel->rectangle = rectangle;
	s->sel->modekeys = modekeys;

	s->sel->sx = sx;
	s->sel->sy = sy;
	s->sel->ex = ex;
	s->sel->ey = ey;
	}

	/* Clear selection. */
	void
	screen_clear_selection(struct screen *s)
	{
	free(s->sel);
	s->sel = NULL;
	}

	/* Hide selection. */
	void
	screen_hide_selection(struct screen *s)
	{
	if (s->sel != NULL)
	s->sel->hidden = 1;
	}

	/* Check if cell in selection. */
	int
	screen_check_selection(struct screen *s, u_int px, u_int py)
	{
	struct screen_sel *sel = s->sel;
	u_int xx;

	if (sel == NULL \|\| sel->hidden)
	return (0);

	if (sel->rectangle) {
	if (sel->sy < sel->ey) {
	/* start line < end line -- downward selection. */
	if (py < sel->sy \|\| py > sel->ey)
	return (0);
	} else if (sel->sy > sel->ey) {
	/* start line > end line -- upward selection. */
	if (py > sel->sy \|\| py < sel->ey)
	return (0);
	} else {
	/* starting line == ending line. */
	if (py != sel->sy)
	return (0);
	}

	/*
	* Need to include the selection start row, but not the cursor
	* row, which means the selection changes depending on which
	* one is on the left.
	*/
	if (sel->ex < sel->sx) {
	/* Cursor (ex) is on the left. */
	if (px < sel->ex)
	return (0);

	if (px > sel->sx)
	return (0);
	} else {
	/* Selection start (sx) is on the left. */
	if (px < sel->sx)
	return (0);

	if (px > sel->ex)
	return (0);
	}
	} else {
	/*
	* Like emacs, keep the top-left-most character, and drop the
	* bottom-right-most, regardless of copy direction.
	*/
	if (sel->sy < sel->ey) {
	/* starting line < ending line -- downward selection. */
	if (py < sel->sy \|\| py > sel->ey)
	return (0);

	if (py == sel->sy && px < sel->sx)
	return (0);

	if (sel->modekeys == MODEKEY_EMACS)
	xx = (sel->ex == 0 ? 0 : sel->ex - 1);
	else
	xx = sel->ex;
	if (py == sel->ey && px > xx)
	return (0);
	} else if (sel->sy > sel->ey) {
	/* starting line > ending line -- upward selection. */
	if (py > sel->sy \|\| py < sel->ey)
	return (0);

	if (py == sel->ey && px < sel->ex)
	return (0);

	if (sel->modekeys == MODEKEY_EMACS)
	xx = sel->sx - 1;
	else
	xx = sel->sx;
	if (py == sel->sy && (sel->sx == 0 \|\| px > xx))
	return (0);
	} else {
	/* starting line == ending line. */
	if (py != sel->sy)
	return (0);

	if (sel->ex < sel->sx) {
	/* cursor (ex) is on the left */
	if (sel->modekeys == MODEKEY_EMACS)
	xx = sel->sx - 1;
	else
	xx = sel->sx;
	if (px > xx \|\| px < sel->ex)
	return (0);
	} else {
	/* selection start (sx) is on the left */
	if (sel->modekeys == MODEKEY_EMACS)
	xx = (sel->ex == 0 ? 0 : sel->ex - 1);
	else
	xx = sel->ex;
	if (px < sel->sx \|\| px > xx)
	return (0);
	}
	}
	}

	return (1);
	}

	/* Get selected grid cell. */
	void
	screen_select_cell(struct screen s, struct grid_cell dst,
	const struct grid_cell *src)
	{
	if (s->sel == NULL \|\| s->sel->hidden)
	return;

	memcpy(dst, &s->sel->cell, sizeof *dst);

	utf8_copy(&dst->data, &src->data);
	dst->attr = dst->attr & ~GRID_ATTR_CHARSET;
	dst->attr \|= src->attr & GRID_ATTR_CHARSET;
	dst->flags = src->flags;
	}

	/* Reflow wrapped lines. */
	static void
	screen_reflow(struct screen s, u_int new_x, u_int cx, u_int *cy, int cursor)
	{
	u_int wx, wy;

	if (cursor) {
	grid_wrap_position(s->grid, cx, cy, &wx, &wy);
	log_debug("%s: cursor %u,%u is %u,%u", __func__, cx, cy, wx,
	wy);
	}

	grid_reflow(s->grid, new_x);

	if (cursor) {
	grid_unwrap_position(s->grid, cx, cy, wx, wy);
	log_debug("%s: new cursor is %u,%u", __func__, cx, cy);
	}
	else {
	*cx = 0;
	*cy = s->grid->hsize;
	}
	}

	/*
	* Enter alternative screen mode. A copy of the visible screen is saved and the
	* history is not updated.
	*/
	void
	screen_alternate_on(struct screen s, struct grid_cell gc, int cursor)
	{
	u_int sx, sy;

	if (s->saved_grid != NULL)
	return;
	sx = screen_size_x(s);
	sy = screen_size_y(s);

	s->saved_grid = grid_create(sx, sy, 0);
	grid_duplicate_lines(s->saved_grid, 0, s->grid, screen_hsize(s), sy);
	if (cursor) {
	s->saved_cx = s->cx;
	s->saved_cy = s->cy;
	}
	memcpy(&s->saved_cell, gc, sizeof s->saved_cell);

	grid_view_clear(s->grid, 0, 0, sx, sy, 8);

	s->saved_flags = s->grid->flags;
	s->grid->flags &= ~GRID_HISTORY;
	}

	/* Exit alternate screen mode and restore the copied grid. */
	void
	screen_alternate_off(struct screen s, struct grid_cell gc, int cursor)
	{
	u_int sx = screen_size_x(s), sy = screen_size_y(s);

	/*
	* If the current size is different, temporarily resize to the old size
	* before copying back.
	*/
	if (s->saved_grid != NULL)
	screen_resize(s, s->saved_grid->sx, s->saved_grid->sy, 1);

	/*
	* Restore the cursor position and cell. This happens even if not
	* currently in the alternate screen.
	*/
	if (cursor && s->saved_cx != UINT_MAX && s->saved_cy != UINT_MAX) {
	s->cx = s->saved_cx;
	s->cy = s->saved_cy;
	if (gc != NULL)
	memcpy(gc, &s->saved_cell, sizeof *gc);
	}

	/* If not in the alternate screen, do nothing more. */
	if (s->saved_grid == NULL) {
	if (s->cx > screen_size_x(s) - 1)
	s->cx = screen_size_x(s) - 1;
	if (s->cy > screen_size_y(s) - 1)
	s->cy = screen_size_y(s) - 1;
	return;
	}

	/* Restore the saved grid. */
	grid_duplicate_lines(s->grid, screen_hsize(s), s->saved_grid, 0,
	s->saved_grid->sy);

	/*
	* Turn history back on (so resize can use it) and then resize back to
	* the current size.
	*/
	if (s->saved_flags & GRID_HISTORY)
	s->grid->flags \|= GRID_HISTORY;
	screen_resize(s, sx, sy, 1);

	grid_destroy(s->saved_grid);
	s->saved_grid = NULL;

	if (s->cx > screen_size_x(s) - 1)
	s->cx = screen_size_x(s) - 1;
	if (s->cy > screen_size_y(s) - 1)
	s->cy = screen_size_y(s) - 1;
	}

	/* Get mode as a string. */
	const char *
	screen_mode_to_string(int mode)
	{
	static char tmp[1024];

	if (mode == 0)
	return "NONE";
	if (mode == ALL_MODES)
	return "ALL";

	*tmp = '\0';
	if (mode & MODE_CURSOR)
	strlcat(tmp, "CURSOR,", sizeof tmp);
	if (mode & MODE_INSERT)
	strlcat(tmp, "INSERT,", sizeof tmp);
	if (mode & MODE_KCURSOR)
	strlcat(tmp, "KCURSOR,", sizeof tmp);
	if (mode & MODE_KKEYPAD)
	strlcat(tmp, "KKEYPAD,", sizeof tmp);
	if (mode & MODE_WRAP)
	strlcat(tmp, "WRAP,", sizeof tmp);
	if (mode & MODE_MOUSE_STANDARD)
	strlcat(tmp, "STANDARD,", sizeof tmp);
	if (mode & MODE_MOUSE_BUTTON)
	strlcat(tmp, "BUTTON,", sizeof tmp);
	if (mode & MODE_BLINKING)
	strlcat(tmp, "BLINKING,", sizeof tmp);
	if (mode & MODE_MOUSE_UTF8)
	strlcat(tmp, "UTF8,", sizeof tmp);
	if (mode & MODE_MOUSE_SGR)
	strlcat(tmp, "SGR,", sizeof tmp);
	if (mode & MODE_BRACKETPASTE)
	strlcat(tmp, "BRACKETPASTE,", sizeof tmp);
	if (mode & MODE_FOCUSON)
	strlcat(tmp, "FOCUSON,", sizeof tmp);
	if (mode & MODE_MOUSE_ALL)
	strlcat(tmp, "ALL,", sizeof tmp);
	if (mode & MODE_ORIGIN)
	strlcat(tmp, "ORIGIN,", sizeof tmp);
	if (mode & MODE_CRLF)
	strlcat(tmp, "CRLF,", sizeof tmp);
	if (mode & MODE_KEXTENDED)
	strlcat(tmp, "KEXTENDED,", sizeof tmp);
	tmp[strlen (tmp) - 1] = '\0';
	return (tmp);
	}