st

st-columns-rows-reflow-st-unpatched-new.diff (39148B)

---

 From: João F. BeyondMagic <[email protected]>
 Date: Tue, 27 Dec 2021
 Subject: [PATCH] Patch to redraw columns and rows in 
 case of hidden by resize. Extracted from 
 https://github.com/ashish-yadav11/st @ashish-yadav11 
 Source: https://github.com/nimaipatel/st/blob/master/patches/columns-rows-reflow-st-unpatched-new.patch
 diff --git a/st.c b/st.c
 index a9338e1..e3b052d 100644
 --- a/st.c
 +++ b/st.c
 @@ -35,6 +35,8 @@
  #define ESC_ARG_SIZ   16
  #define STR_BUF_SIZ   ESC_BUF_SIZ
  #define STR_ARG_SIZ   ESC_ARG_SIZ
 +#define HISTSIZE      2000
 +#define RESIZEBUFFER  1000
  
  /* macros */
  #define IS_SET(flag)		((term.mode & (flag)) != 0)
 @@ -42,6 +44,24 @@
  #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
  #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
  #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
 +#define STRESCARGREST(n)	((n) == 0 ? strescseq.buf : strescseq.args[(n)-1] + 1)
 +#define STRESCARGJUST(n)	(*(strescseq.args[n]) = '\0', STRESCARGREST(n))
 +
 +#define TLINE(y) ( \
 +	(y) < term.scr ? term.hist[(term.histi + (y) - term.scr + 1 + HISTSIZE) % HISTSIZE] \
 +	               : term.line[(y) - term.scr] \
 +)
 +
 +#define TLINEABS(y) ( \
 +	(y) < 0 ? term.hist[(term.histi + (y) + 1 + HISTSIZE) % HISTSIZE] : term.line[(y)] \
 +)
 +
 +#define UPDATEWRAPNEXT(alt, col) do { \
 +	if ((term.c.state & CURSOR_WRAPNEXT) && term.c.x + term.wrapcwidth[alt] < col) { \
 +		term.c.x += term.wrapcwidth[alt]; \
 +		term.c.state &= ~CURSOR_WRAPNEXT; \
 +	} \
 +} while (0);
  
  enum term_mode {
  	MODE_WRAP        = 1 << 0,
 @@ -53,6 +73,12 @@ enum term_mode {
  	MODE_UTF8        = 1 << 6,
  };
  
 +enum scroll_mode {
 +	SCROLL_RESIZE = -1,
 +	SCROLL_NOSAVEHIST = 0,
 +	SCROLL_SAVEHIST = 1
 +};
 +
  enum cursor_movement {
  	CURSOR_SAVE,
  	CURSOR_LOAD
 @@ -114,7 +140,11 @@ typedef struct {
  	int row;      /* nb row */
  	int col;      /* nb col */
  	Line *line;   /* screen */
 -	Line *alt;    /* alternate screen */
 + 	Line hist[HISTSIZE]; /* history buffer */
 +	int histi;           /* history index */
 +	int histf;           /* nb history available */
 +	int scr;             /* scroll back */
 +	int wrapcwidth[2];   /* used in updating WRAPNEXT when resizing */
  	int *dirty;   /* dirtyness of lines */
  	TCursor c;    /* cursor */
  	int ocx;      /* old cursor col */
 @@ -171,26 +201,37 @@ static void tprinter(char *, size_t);
  static void tdumpsel(void);
  static void tdumpline(int);
  static void tdump(void);
 -static void tclearregion(int, int, int, int);
 +static void tclearregion(int, int, int, int, int);
  static void tcursor(int);
 +static void tclearglyph(Glyph *, int);
 +static void tresetcursor(void);
  static void tdeletechar(int);
  static void tdeleteline(int);
  static void tinsertblank(int);
  static void tinsertblankline(int);
 -static int tlinelen(int);
 +static int tlinelen(Line len);
 +static int tiswrapped(Line line);
 +static char *tgetglyphs(char *, const Glyph *, const Glyph *);
 +static size_t tgetline(char *, const Glyph *);
  static void tmoveto(int, int);
  static void tmoveato(int, int);
  static void tnewline(int);
  static void tputtab(int);
  static void tputc(Rune);
  static void treset(void);
 -static void tscrollup(int, int);
 +static void tscrollup(int, int, int, int);
  static void tscrolldown(int, int);
 +static void treflow(int, int);
 +static void rscrolldown(int);
 +static void tresizedef(int, int);
 +static void tresizealt(int, int);
  static void tsetattr(const int *, int);
  static void tsetchar(Rune, const Glyph *, int, int);
  static void tsetdirt(int, int);
  static void tsetscroll(int, int);
  static void tswapscreen(void);
 +static void tloaddefscreen(int, int);
 +static void tloadaltscreen(int, int);
  static void tsetmode(int, int, const int *, int);
  static int twrite(const char *, int, int);
  static void tfulldirt(void);
 @@ -204,7 +245,10 @@ static void tstrsequence(uchar);
  static void drawregion(int, int, int, int);
  
  static void selnormalize(void);
 -static void selscroll(int, int);
 +static void selscroll(int, int, int);
 +static void selmove(int);
 +static void selremove(void);
 +static int regionselected(int, int, int, int);
  static void selsnap(int *, int *, int);
  
  static size_t utf8decode(const char *, Rune *, size_t);
 @@ -412,17 +456,46 @@ selinit(void)
  }
  
  int
 -tlinelen(int y)
 +tlinelen(Line line)
  {
 -	int i = term.col;
 +	int i = term.col - 1;
 +
 +	for (; i >= 0 && !(line[i].mode & (ATTR_SET | ATTR_WRAP)); i--);
 +	return i + 1;
 +}
  
 -	if (term.line[y][i - 1].mode & ATTR_WRAP)
 -		return i;
 +int
 +tiswrapped(Line line)
 +{
 +	int len = tlinelen(line);
  
 -	while (i > 0 && term.line[y][i - 1].u == ' ')
 -		--i;
 +	return len > 0 && (line[len - 1].mode & ATTR_WRAP);
 +}
  
 -	return i;
 +char *
 +tgetglyphs(char *buf, const Glyph *gp, const Glyph *lgp)
 +{
 +	while (gp <= lgp)
 +		if (gp->mode & ATTR_WDUMMY) {
 +			gp++;
 +		} else {
 +			buf += utf8encode((gp++)->u, buf);
 +		}
 +	return buf;
 +}
 +
 +size_t
 +tgetline(char *buf, const Glyph *fgp)
 +{
 +	char *ptr;
 +	const Glyph *lgp = &fgp[term.col - 1];
 +
 +	while (lgp > fgp && !(lgp->mode & (ATTR_SET | ATTR_WRAP)))
 +		lgp--;
 +	ptr = tgetglyphs(buf, fgp, lgp);
 +	if (!(lgp->mode & ATTR_WRAP))
 +		*(ptr++) = '\n';
 +	return ptr - buf;
  }
  
  void
 @@ -462,10 +535,11 @@ selextend(int col, int row, int type, int done)
  
  	sel.oe.x = col;
  	sel.oe.y = row;
 -	selnormalize();
  	sel.type = type;
 +	selnormalize();
  
 -	if (oldey != sel.oe.y || oldex != sel.oe.x || oldtype != sel.type || sel.mode == SEL_EMPTY)
 +	if (oldey != sel.oe.y || oldex != sel.oe.x ||
 +	    oldtype != sel.type || sel.mode == SEL_EMPTY)
  		tsetdirt(MIN(sel.nb.y, oldsby), MAX(sel.ne.y, oldsey));
  
  	sel.mode = done ? SEL_IDLE : SEL_READY;
 @@ -489,46 +563,53 @@ selnormalize(void)
  	selsnap(&sel.nb.x, &sel.nb.y, -1);
  	selsnap(&sel.ne.x, &sel.ne.y, +1);
  
 -	/* expand selection over line breaks */
 +  /* expand selection over line breaks */
  	if (sel.type == SEL_RECTANGULAR)
  		return;
 -	i = tlinelen(sel.nb.y);
 -	if (i < sel.nb.x)
 +
 +  i = tlinelen(TLINE(sel.nb.y));
 +	if (sel.nb.x > i)
  		sel.nb.x = i;
 -	if (tlinelen(sel.ne.y) <= sel.ne.x)
 -		sel.ne.x = term.col - 1;
 +  if (sel.ne.x >= tlinelen(TLINE(sel.ne.y)))
 +    sel.ne.x = term.col - 1;
  }
  
  int
 -selected(int x, int y)
 +regionselected(int x1, int y1, int x2, int y2)
  {
 -	if (sel.mode == SEL_EMPTY || sel.ob.x == -1 ||
 -			sel.alt != IS_SET(MODE_ALTSCREEN))
 +	if (sel.ob.x == -1 || sel.mode == SEL_EMPTY ||
 +	    sel.alt != IS_SET(MODE_ALTSCREEN) || sel.nb.y > y2 || sel.ne.y < y1)
  		return 0;
  
 -	if (sel.type == SEL_RECTANGULAR)
 -		return BETWEEN(y, sel.nb.y, sel.ne.y)
 -		    && BETWEEN(x, sel.nb.x, sel.ne.x);
 +	return (sel.type == SEL_RECTANGULAR) ? sel.nb.x <= x2 && sel.ne.x >= x1
 +		: (sel.nb.y != y2 || sel.nb.x <= x2) &&
 +		  (sel.ne.y != y1 || sel.ne.x >= x1);
 +}
  
 -	return BETWEEN(y, sel.nb.y, sel.ne.y)
 -	    && (y != sel.nb.y || x >= sel.nb.x)
 -	    && (y != sel.ne.y || x <= sel.ne.x);
 +int
 +selected(int x, int y)
 +{
 +	return regionselected(x, y, x, y);
  }
  
  void
  selsnap(int *x, int *y, int direction)
  {
  	int newx, newy, xt, yt;
 +	int rtop = 0, rbot = term.row - 1;
  	int delim, prevdelim;
  	const Glyph *gp, *prevgp;
  
 +	if (!IS_SET(MODE_ALTSCREEN))
 +		rtop += -term.histf + term.scr, rbot += term.scr;
 +
  	switch (sel.snap) {
  	case SNAP_WORD:
  		/*
  		 * Snap around if the word wraps around at the end or
  		 * beginning of a line.
  		 */
 -		prevgp = &term.line[*y][*x];
 +		prevgp = &TLINE(*y)[*x];
  		prevdelim = ISDELIM(prevgp->u);
  		for (;;) {
  			newx = *x + direction;
 @@ -536,24 +617,24 @@ selsnap(int *x, int *y, int direction)
  			if (!BETWEEN(newx, 0, term.col - 1)) {
  				newy += direction;
  				newx = (newx + term.col) % term.col;
 -				if (!BETWEEN(newy, 0, term.row - 1))
 +				if (!BETWEEN(newy, rtop, rbot))
  					break;
  
  				if (direction > 0)
  					yt = *y, xt = *x;
  				else
  					yt = newy, xt = newx;
 -				if (!(term.line[yt][xt].mode & ATTR_WRAP))
 +				if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
  					break;
  			}
  
 -			if (newx >= tlinelen(newy))
 +			if (newx >= tlinelen(TLINE(newy)))
  				break;
  
 -			gp = &term.line[newy][newx];
 +			gp = &TLINE(newy)[newx];
  			delim = ISDELIM(gp->u);
 -			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
 -					|| (delim && gp->u != prevgp->u)))
 +			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim ||
 +			    (delim && !(gp->u == ' ' && prevgp->u == ' '))))
  				break;
  
  			*x = newx;
 @@ -570,18 +651,14 @@ selsnap(int *x, int *y, int direction)
  		 */
  		*x = (direction < 0) ? 0 : term.col - 1;
  		if (direction < 0) {
 -			for (; *y > 0; *y += direction) {
 -				if (!(term.line[*y-1][term.col-1].mode
 -						& ATTR_WRAP)) {
 +			for (; *y > rtop; *y -= 1) {
 +				if (!tiswrapped(TLINE(*y-1)))
  					break;
 -				}
  			}
  		} else if (direction > 0) {
 -			for (; *y < term.row-1; *y += direction) {
 -				if (!(term.line[*y][term.col-1].mode
 -						& ATTR_WRAP)) {
 +			for (; *y < rbot; *y += 1) {
 +				if (!tiswrapped(TLINE(*y)))
  					break;
 -				}
  			}
  		}
  		break;
 @@ -592,40 +669,34 @@ char *
  getsel(void)
  {
  	char *str, *ptr;
 -	int y, bufsize, lastx, linelen;
 -	const Glyph *gp, *last;
 +	int y, lastx, linelen;
 +	const Glyph *gp, *lgp;
  
 -	if (sel.ob.x == -1)
 +	if (sel.ob.x == -1 || sel.alt != IS_SET(MODE_ALTSCREEN))
  		return NULL;
  
 -	bufsize = (term.col+1) * (sel.ne.y-sel.nb.y+1) * UTF_SIZ;
 -	ptr = str = xmalloc(bufsize);
 +	str = xmalloc((term.col + 1) * (sel.ne.y - sel.nb.y + 1) * UTF_SIZ);
 +	ptr = str;
  
  	/* append every set & selected glyph to the selection */
  	for (y = sel.nb.y; y <= sel.ne.y; y++) {
 -		if ((linelen = tlinelen(y)) == 0) {
 +		Line line = TLINE(y);
 +
 +		if ((linelen = tlinelen(line)) == 0) {
  			*ptr++ = '\n';
  			continue;
  		}
  
  		if (sel.type == SEL_RECTANGULAR) {
 -			gp = &term.line[y][sel.nb.x];
 +			gp = &line[sel.nb.x];
  			lastx = sel.ne.x;
  		} else {
 -			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
 +			gp = &line[sel.nb.y == y ? sel.nb.x : 0];
  			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
  		}
 -		last = &term.line[y][MIN(lastx, linelen-1)];
 -		while (last >= gp && last->u == ' ')
 -			--last;
 -
 -		for ( ; gp <= last; ++gp) {
 -			if (gp->mode & ATTR_WDUMMY)
 -				continue;
 -
 -			ptr += utf8encode(gp->u, ptr);
 -		}
 +		lgp = &line[MIN(lastx, linelen-1)];
  
 +		ptr = tgetglyphs(ptr, gp, lgp);
  		/*
  		 * Copy and pasting of line endings is inconsistent
  		 * in the inconsistent terminal and GUI world.
 @@ -636,10 +707,10 @@ getsel(void)
  		 * FIXME: Fix the computer world.
  		 */
  		if ((y < sel.ne.y || lastx >= linelen) &&
 -		    (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
 +		    (!(lgp->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
  			*ptr++ = '\n';
  	}
 -	*ptr = 0;
 +	*ptr = '\0';
  	return str;
  }
  
 @@ -648,9 +719,15 @@ selclear(void)
  {
  	if (sel.ob.x == -1)
  		return;
 +	selremove();
 +	tsetdirt(sel.nb.y, sel.ne.y);
 +}
 +
 +void
 +selremove(void)
 +{
  	sel.mode = SEL_IDLE;
  	sel.ob.x = -1;
 -	tsetdirt(sel.nb.y, sel.ne.y);
  }
  
  void
 @@ -852,6 +929,7 @@ ttywrite(const char *s, size_t n, int may_echo)
  {
  	const char *next;
  
 +	kscrolldown(&((Arg){ .i = term.scr }));
  	if (may_echo && IS_SET(MODE_ECHO))
  		twrite(s, n, 1);
  
 @@ -987,7 +1065,7 @@ tsetdirtattr(int attr)
  	for (i = 0; i < term.row-1; i++) {
  		for (j = 0; j < term.col-1; j++) {
  			if (term.line[i][j].mode & attr) {
 -				tsetdirt(i, i);
 +				term.dirty[i] = 1;
  				break;
  			}
  		}
 @@ -997,7 +1075,8 @@ tsetdirtattr(int attr)
  void
  tfulldirt(void)
  {
 -	tsetdirt(0, term.row-1);
 +  for (int i = 0; i < term.row; i++)
 +		term.dirty[i] = 1;
  }
  
  void
 @@ -1014,110 +1093,259 @@ tcursor(int mode)
  	}
  }
  
 +void
 +tresetcursor(void)
 +{
 +	term.c = (TCursor){ { .mode = ATTR_NULL, .fg = defaultfg, .bg = defaultbg },
 +	                    .x = 0, .y = 0, .state = CURSOR_DEFAULT };
 +}
 +
  void
  treset(void)
  {
  	uint i;
 +  int x, y;
  
 -	term.c = (TCursor){{
 -		.mode = ATTR_NULL,
 -		.fg = defaultfg,
 -		.bg = defaultbg
 -	}, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
 +	tresetcursor();
  
  	memset(term.tabs, 0, term.col * sizeof(*term.tabs));
  	for (i = tabspaces; i < term.col; i += tabspaces)
  		term.tabs[i] = 1;
  	term.top = 0;
 +	term.histf = 0;
 +	term.scr = 0;
  	term.bot = term.row - 1;
  	term.mode = MODE_WRAP|MODE_UTF8;
  	memset(term.trantbl, CS_USA, sizeof(term.trantbl));
  	term.charset = 0;
  
 +  selremove();
  	for (i = 0; i < 2; i++) {
 -		tmoveto(0, 0);
 -		tcursor(CURSOR_SAVE);
 -		tclearregion(0, 0, term.col-1, term.row-1);
 +  	tcursor(CURSOR_SAVE); /* reset saved cursor */
 +		for (y = 0; y < term.row; y++)
 +			for (x = 0; x < term.col; x++)
 +				tclearglyph(&term.line[y][x], 0);
  		tswapscreen();
  	}
 +  tfulldirt();
  }
  
  void
  tnew(int col, int row)
  {
 -	term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
 -	tresize(col, row);
 -	treset();
 +	int i, j;
 +
 +	for (i = 0; i < 2; i++) {
 +		term.line = xmalloc(row * sizeof(Line));
 +		for (j = 0; j < row; j++)
 +			term.line[j] = xmalloc(col * sizeof(Glyph));
 +		term.col = col, term.row = row;
 +		tswapscreen();
 +	}
 +	term.dirty = xmalloc(row * sizeof(*term.dirty));
 +	term.tabs = xmalloc(col * sizeof(*term.tabs));
 +	for (i = 0; i < HISTSIZE; i++)
 +		term.hist[i] = xmalloc(col * sizeof(Glyph));
 +  treset();
  }
  
 +/* handle it with care */
  void
  tswapscreen(void)
  {
 -	Line *tmp = term.line;
 +	static Line *altline;
 +	static int altcol, altrow;
 +	Line *tmpline = term.line;
 +	int tmpcol = term.col, tmprow = term.row;
  
 -	term.line = term.alt;
 -	term.alt = tmp;
 +	term.line = altline;
 +	term.col = altcol, term.row = altrow;
 +	altline = tmpline;
 +	altcol = tmpcol, altrow = tmprow;
  	term.mode ^= MODE_ALTSCREEN;
 +}
 +
 +void
 +tloaddefscreen(int clear, int loadcursor)
 +{
 +	int col, row, alt = IS_SET(MODE_ALTSCREEN);
 +
 +	if (alt) {
 +		if (clear)
 +			tclearregion(0, 0, term.col-1, term.row-1, 1);
 +		col = term.col, row = term.row;
 +		tswapscreen();
 +	}
 +	if (loadcursor)
 +		tcursor(CURSOR_LOAD);
 +	if (alt)
 +		tresizedef(col, row);
 +}
 +
 +void
 +tloadaltscreen(int clear, int savecursor)
 +{
 +	int col, row, def = !IS_SET(MODE_ALTSCREEN);
 +
 +	if (savecursor)
 +		tcursor(CURSOR_SAVE);
 +	if (def) {
 +		col = term.col, row = term.row;
 +		tswapscreen();
 +		term.scr = 0;
 +		tresizealt(col, row);
 +	}
 +	if (clear)
 +		tclearregion(0, 0, term.col-1, term.row-1, 1);
 +}
 +
 +int
 +tisaltscreen(void)
 +{
 +	return IS_SET(MODE_ALTSCREEN);
 +}
 +
 +void
 +kscrolldown(const Arg* a)
 +{
 +	int n = a->i;
 +
 +	if (!term.scr || IS_SET(MODE_ALTSCREEN))
 +		return;
 +
 +	if (n < 0)
 +		n = MAX(term.row / -n, 1);
 +
 +	if (n <= term.scr) {
 +		term.scr -= n;
 +	} else {
 +		n = term.scr;
 +		term.scr = 0;
 +	}
 +
 +	if (sel.ob.x != -1 && !sel.alt)
 +		selmove(-n); /* negate change in term.scr */
  	tfulldirt();
  }
  
  void
 -tscrolldown(int orig, int n)
 +kscrollup(const Arg* a)
  {
 -	int i;
 +	int n = a->i;
 +
 +	if (!term.histf || IS_SET(MODE_ALTSCREEN))
 +		return;
 +
 +	if (n < 0)
 +		n = MAX(term.row / -n, 1);
 +
 +	if (term.scr + n <= term.histf) {
 +		term.scr += n;
 +	} else {
 +		n = term.histf - term.scr;
 +		term.scr = term.histf;
 +	}
 +
 +	if (sel.ob.x != -1 && !sel.alt)
 +		selmove(n); /* negate change in term.scr */
 +	tfulldirt();
 +}
 +
 +void
 +tscrolldown(int top, int n)
 +{
 +	int i, bot = term.bot;
  	Line temp;
  
 -	LIMIT(n, 0, term.bot-orig+1);
 +	if (n <= 0)
 +		return;
 +	n = MIN(n, bot-top+1);
  
 -	tsetdirt(orig, term.bot-n);
 -	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 +	tsetdirt(top, bot-n);
 +	tclearregion(0, bot-n+1, term.col-1, bot, 1);
  
 -	for (i = term.bot; i >= orig+n; i--) {
 +	for (i = bot; i >= top+n; i--) {
  		temp = term.line[i];
  		term.line[i] = term.line[i-n];
  		term.line[i-n] = temp;
  	}
  
 -	selscroll(orig, n);
 +	if (sel.ob.x != -1 && sel.alt == IS_SET(MODE_ALTSCREEN))
 +		selscroll(top, bot, n);
  }
  
  void
 -tscrollup(int orig, int n)
 +tscrollup(int top, int bot, int n, int mode)
  {
 -	int i;
 +	int i, j, s;
 +	int alt = IS_SET(MODE_ALTSCREEN);
 +	int savehist = !alt && top == 0 && mode != SCROLL_NOSAVEHIST;
  	Line temp;
  
 -	LIMIT(n, 0, term.bot-orig+1);
 +	if (n <= 0)
 +		return;
 +	n = MIN(n, bot-top+1);
 +
 +	if (savehist) {
 +		for (i = 0; i < n; i++) {
 +			term.histi = (term.histi + 1) % HISTSIZE;
 +			temp = term.hist[term.histi];
 +			for (j = 0; j < term.col; j++)
 +				tclearglyph(&temp[j], 1);
 +			term.hist[term.histi] = term.line[i];
 +			term.line[i] = temp;
 +		}
 +		term.histf = MIN(term.histf + n, HISTSIZE);
 +		s = n;
 +		if (term.scr) {
 +			j = term.scr;
 +			term.scr = MIN(j + n, HISTSIZE);
 +			s = j + n - term.scr;
 +		}
 +		if (mode != SCROLL_RESIZE)
 +			tfulldirt();
 +	} else {
 +		tclearregion(0, top, term.col-1, top+n-1, 1);
 +		tsetdirt(top+n, bot);
 +	}
  
 -	tclearregion(0, orig, term.col-1, orig+n-1);
 -	tsetdirt(orig+n, term.bot);
  
 -	for (i = orig; i <= term.bot-n; i++) {
 +	for (i = top; i <= bot-n; i++) {
  		temp = term.line[i];
  		term.line[i] = term.line[i+n];
  		term.line[i+n] = temp;
  	}
  
 -	selscroll(orig, -n);
 +	if (sel.ob.x != -1 && sel.alt == alt) {
 +		if (!savehist) {
 +			selscroll(top, bot, -n);
 +		} else if (s > 0) {
 +			selmove(-s);
 +			if (-term.scr + sel.nb.y < -term.histf)
 +				selremove();
 +		}
 +	}
  }
  
  void
 -selscroll(int orig, int n)
 +selmove(int n)
  {
 -	if (sel.ob.x == -1)
 -		return;
 +	sel.ob.y += n, sel.nb.y += n;
 +	sel.oe.y += n, sel.ne.y += n;
 +}
 +
 +void
 +selscroll(int top, int bot, int n)
 +{
 +	/* turn absolute coordinates into relative */
 +	top += term.scr, bot += term.scr;
  
 -	if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig, term.bot)) {
 +	if (BETWEEN(sel.nb.y, top, bot) != BETWEEN(sel.ne.y, top, bot)) {
  		selclear();
 -	} else if (BETWEEN(sel.nb.y, orig, term.bot)) {
 -		sel.ob.y += n;
 -		sel.oe.y += n;
 -		if (sel.ob.y < term.top || sel.ob.y > term.bot ||
 -		    sel.oe.y < term.top || sel.oe.y > term.bot) {
 +	} else if (BETWEEN(sel.nb.y, top, bot)) {
 +		selmove(n);
 +		if (sel.nb.y < top || sel.ne.y > bot)
  			selclear();
 -		} else {
 -			selnormalize();
 -		}
  	}
  }
  
 @@ -1127,7 +1355,7 @@ tnewline(int first_col)
  	int y = term.c.y;
  
  	if (y == term.bot) {
 -		tscrollup(term.top, 1);
 +		tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIST);
  	} else {
  		y++;
  	}
 @@ -1217,75 +1445,79 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
  	} else if (term.line[y][x].mode & ATTR_WDUMMY) {
  		term.line[y][x-1].u = ' ';
  		term.line[y][x-1].mode &= ~ATTR_WIDE;
 -	}
 +  }
  
  	term.dirty[y] = 1;
  	term.line[y][x] = *attr;
  	term.line[y][x].u = u;
 +	term.line[y][x].mode |= ATTR_SET;
  }
  
  void
 -tclearregion(int x1, int y1, int x2, int y2)
 +tclearglyph(Glyph *gp, int usecurattr)
  {
 -	int x, y, temp;
 -	Glyph *gp;
 +	if (usecurattr) {
 +		gp->fg = term.c.attr.fg;
 +		gp->bg = term.c.attr.bg;
 +	} else {
 +		gp->fg = defaultfg;
 +		gp->bg = defaultbg;
 +	}
 +	gp->mode = ATTR_NULL;
 +	gp->u = ' ';
 +}
  
 -	if (x1 > x2)
 -		temp = x1, x1 = x2, x2 = temp;
 -	if (y1 > y2)
 -		temp = y1, y1 = y2, y2 = temp;
 +void
 +tclearregion(int x1, int y1, int x2, int y2, int usecurattr)
 +{
 +	int x, y;
  
 -	LIMIT(x1, 0, term.col-1);
 -	LIMIT(x2, 0, term.col-1);
 -	LIMIT(y1, 0, term.row-1);
 -	LIMIT(y2, 0, term.row-1);
 +	/* regionselected() takes relative coordinates */
 +	if (regionselected(x1+term.scr, y1+term.scr, x2+term.scr, y2+term.scr))
 +		selremove();
  
  	for (y = y1; y <= y2; y++) {
  		term.dirty[y] = 1;
 -		for (x = x1; x <= x2; x++) {
 -			gp = &term.line[y][x];
 -			if (selected(x, y))
 -				selclear();
 -			gp->fg = term.c.attr.fg;
 -			gp->bg = term.c.attr.bg;
 -			gp->mode = 0;
 -			gp->u = ' ';
 -		}
 +		for (x = x1; x <= x2; x++)
 +			tclearglyph(&term.line[y][x], usecurattr);
  	}
  }
  
  void
  tdeletechar(int n)
  {
 -	int dst, src, size;
 -	Glyph *line;
 -
 -	LIMIT(n, 0, term.col - term.c.x);
 +	int src, dst, size;
 +	Line line;
  
 +	if (n <= 0)
 +		return;
  	dst = term.c.x;
 -	src = term.c.x + n;
 +	src = MIN(term.c.x + n, term.col);
  	size = term.col - src;
 -	line = term.line[term.c.y];
 -
 -	memmove(&line[dst], &line[src], size * sizeof(Glyph));
 -	tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
 +	if (size > 0) { /* otherwise src would point beyond the array
 +	                   https://stackoverflow.com/questions/29844298 */
 +		line = term.line[term.c.y];
 +		memmove(&line[dst], &line[src], size * sizeof(Glyph));
 +	}
 +	tclearregion(dst + size, term.c.y, term.col - 1, term.c.y, 1);
  }
  
  void
  tinsertblank(int n)
  {
 -	int dst, src, size;
 -	Glyph *line;
 -
 -	LIMIT(n, 0, term.col - term.c.x);
 +	int src, dst, size;
 +	Line line;
  
 -	dst = term.c.x + n;
 +	if (n <= 0)
 +		return;
 +	dst = MIN(term.c.x + n, term.col);
  	src = term.c.x;
  	size = term.col - dst;
 -	line = term.line[term.c.y];
 -
 -	memmove(&line[dst], &line[src], size * sizeof(Glyph));
 -	tclearregion(src, term.c.y, dst - 1, term.c.y);
 +	if (size > 0) { /* otherwise dst would point beyond the array */
 +		line = term.line[term.c.y];
 +		memmove(&line[dst], &line[src], size * sizeof(Glyph));
 +	}
 +	tclearregion(src, term.c.y, dst - 1, term.c.y, 1);
  }
  
  void
 @@ -1299,7 +1531,7 @@ void
  tdeleteline(int n)
  {
  	if (BETWEEN(term.c.y, term.top, term.bot))
 -		tscrollup(term.c.y, n);
 +		tscrollup(term.c.y, term.bot, n, SCROLL_NOSAVEHIST);
  }
  
  int32_t
 @@ -1473,7 +1705,7 @@ tsetscroll(int t, int b)
  void
  tsetmode(int priv, int set, const int *args, int narg)
  {
 -	int alt; const int *lim;
 +	const int *lim;
  
  	for (lim = args + narg; args < lim; ++args) {
  		if (priv) {
 @@ -1534,25 +1766,18 @@ tsetmode(int priv, int set, const int *args, int narg)
  				xsetmode(set, MODE_8BIT);
  				break;
  			case 1049: /* swap screen & set/restore cursor as xterm */
 -				if (!allowaltscreen)
 -					break;
 -				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
 -				/* FALLTHROUGH */
  			case 47: /* swap screen */
 -			case 1047:
 +			case 1047: /* swap screen, clearing alternate screen */
  				if (!allowaltscreen)
  					break;
 -				alt = IS_SET(MODE_ALTSCREEN);
 -				if (alt) {
 -					tclearregion(0, 0, term.col-1,
 -							term.row-1);
 -				}
 -				if (set ^ alt) /* set is always 1 or 0 */
 -					tswapscreen();
 -				if (*args != 1049)
 -					break;
 -				/* FALLTHROUGH */
 +				if (set)
 +					tloadaltscreen(*args == 1049, *args == 1049);
 +				else
 +					tloaddefscreen(*args == 1047, *args == 1049);
 +				break;
  			case 1048:
 +				if (!allowaltscreen)
 +          break;
  				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
  				break;
  			case 2004: /* 2004: bracketed paste mode */
 @@ -1604,7 +1829,7 @@ void
  csihandle(void)
  {
  	char buf[40];
 -	int len;
 +	int n, x;
  
  	switch (csiescseq.mode[0]) {
  	default:
 @@ -1702,20 +1927,30 @@ csihandle(void)
  	case 'J': /* ED -- Clear screen */
  		switch (csiescseq.arg[0]) {
  		case 0: /* below */
 -			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
 +			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 1);
  			if (term.c.y < term.row-1) {
 -				tclearregion(0, term.c.y+1, term.col-1,
 -						term.row-1);
 +				tclearregion(0, term.c.y+1, term.col-1, term.row-1, 1);
  			}
  			break;
  		case 1: /* above */
 -			if (term.c.y > 1)
 -				tclearregion(0, 0, term.col-1, term.c.y-1);
 -			tclearregion(0, term.c.y, term.c.x, term.c.y);
 +			if (term.c.y >= 1)
 +				tclearregion(0, 0, term.col-1, term.c.y-1, 1);
 +			tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
  			break;
  		case 2: /* all */
 -			tclearregion(0, 0, term.col-1, term.row-1);
 -			break;
 +			if (IS_SET(MODE_ALTSCREEN)) {
 +  			tclearregion(0, 0, term.col-1, term.row-1, 1);
 +  			break;
 +      }
 +			/* vte does this:
 +			tscrollup(0, term.row-1, term.row, SCROLL_SAVEHIST); */
 +      
 +			/* alacritty does this: */
 +			for (n = term.row-1; n >= 0 && tlinelen(term.line[n]) == 0; n--);
 +			if (n >= 0)
 +				tscrollup(0, term.row-1, n+1, SCROLL_SAVEHIST);
 +			tscrollup(0, term.row-1, term.row-n-1, SCROLL_NOSAVEHIST);
 +      break;
  		default:
  			goto unknown;
  		}
 @@ -1723,20 +1958,20 @@ csihandle(void)
  	case 'K': /* EL -- Clear line */
  		switch (csiescseq.arg[0]) {
  		case 0: /* right */
 -			tclearregion(term.c.x, term.c.y, term.col-1,
 -					term.c.y);
 +			tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 1);
  			break;
  		case 1: /* left */
 -			tclearregion(0, term.c.y, term.c.x, term.c.y);
 +			tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
  			break;
  		case 2: /* all */
 -			tclearregion(0, term.c.y, term.col-1, term.c.y);
 +			tclearregion(0, term.c.y, term.col-1, term.c.y, 1);
  			break;
  		}
  		break;
  	case 'S': /* SU -- Scroll <n> line up */
  		DEFAULT(csiescseq.arg[0], 1);
 -		tscrollup(term.top, csiescseq.arg[0]);
 +		/* xterm, urxvt, alacritty save this in history */
 +		tscrollup(term.top, term.bot, csiescseq.arg[0], SCROLL_SAVEHIST);
  		break;
  	case 'T': /* SD -- Scroll <n> line down */
  		DEFAULT(csiescseq.arg[0], 1);
 @@ -1754,9 +1989,11 @@ csihandle(void)
  		tdeleteline(csiescseq.arg[0]);
  		break;
  	case 'X': /* ECH -- Erase <n> char */
 +		if (csiescseq.arg[0] < 0)
 +			return;
  		DEFAULT(csiescseq.arg[0], 1);
 -		tclearregion(term.c.x, term.c.y,
 -				term.c.x + csiescseq.arg[0] - 1, term.c.y);
 +		x = MIN(term.c.x + csiescseq.arg[0], term.col) - 1;
 +		tclearregion(term.c.x, term.c.y, x, term.c.y, 1);
  		break;
  	case 'P': /* DCH -- Delete <n> char */
  		DEFAULT(csiescseq.arg[0], 1);
 @@ -1778,9 +2015,9 @@ csihandle(void)
  		break;
  	case 'n': /* DSR – Device Status Report (cursor position) */
  		if (csiescseq.arg[0] == 6) {
 -			len = snprintf(buf, sizeof(buf), "\033[%i;%iR",
 +			n = snprintf(buf, sizeof(buf), "\033[%i;%iR",
  					term.c.y+1, term.c.x+1);
 -			ttywrite(buf, len, 0);
 +			ttywrite(buf, n, 0);
  		}
  		break;
  	case 'r': /* DECSTBM -- Set Scrolling Region */
 @@ -1849,29 +2086,30 @@ strhandle(void)
  	int j, narg, par;
  
  	term.esc &= ~(ESC_STR_END|ESC_STR);
 -	strparse();
 -	par = (narg = strescseq.narg) ? atoi(strescseq.args[0]) : 0;
 +	strescseq.buf[strescseq.len] = '\0';
  
  	switch (strescseq.type) {
  	case ']': /* OSC -- Operating System Command */
 +		strparse();
 +		par = (narg = strescseq.narg) ? atoi(STRESCARGJUST(0)) : 0;
  		switch (par) {
  		case 0:
  			if (narg > 1) {
 -				xsettitle(strescseq.args[1]);
 -				xseticontitle(strescseq.args[1]);
 +				xsettitle(STRESCARGREST(1));
 +				xseticontitle(STRESCARGREST(1));
  			}
  			return;
  		case 1:
  			if (narg > 1)
 -				xseticontitle(strescseq.args[1]);
 +				xseticontitle(STRESCARGREST(1));
  			return;
  		case 2:
  			if (narg > 1)
 -				xsettitle(strescseq.args[1]);
 +				xsettitle(STRESCARGREST(1));
  			return;
  		case 52:
  			if (narg > 2 && allowwindowops) {
 -				dec = base64dec(strescseq.args[2]);
 +				dec = base64dec(STRESCARGREST(1));
  				if (dec) {
  					xsetsel(dec);
  					xclipcopy();
 @@ -1883,10 +2121,10 @@ strhandle(void)
  		case 4: /* color set */
  			if (narg < 3)
  				break;
 -			p = strescseq.args[2];
 +			p = STRESCARGREST(2);
  			/* FALLTHROUGH */
  		case 104: /* color reset, here p = NULL */
 -			j = (narg > 1) ? atoi(strescseq.args[1]) : -1;
 +			j = (narg > 1) ? atoi(STRESCARGREST(1)) : -1;
  			if (xsetcolorname(j, p)) {
  				if (par == 104 && narg <= 1)
  					return; /* color reset without parameter */
 @@ -1903,7 +2141,7 @@ strhandle(void)
  		}
  		break;
  	case 'k': /* old title set compatibility */
 -		xsettitle(strescseq.args[0]);
 +		xsettitle(STRESCARGREST(0));
  		return;
  	case 'P': /* DCS -- Device Control String */
  	case '_': /* APC -- Application Program Command */
 @@ -1922,19 +2160,18 @@ strparse(void)
  	char *p = strescseq.buf;
  
  	strescseq.narg = 0;
 -	strescseq.buf[strescseq.len] = '\0';
  
  	if (*p == '\0')
  		return;
  
  	while (strescseq.narg < STR_ARG_SIZ) {
 -		strescseq.args[strescseq.narg++] = p;
  		while ((c = *p) != ';' && c != '\0')
 -			++p;
 +			p++;
 +		strescseq.args[strescseq.narg++] = p;
  		if (c == '\0')
  			return;
 -		*p++ = '\0';
 -	}
 +		p++;
 +  }
  }
  
  void
 @@ -2022,16 +2259,8 @@ tdumpsel(void)
  void
  tdumpline(int n)
  {
 -	char buf[UTF_SIZ];
 -	const Glyph *bp, *end;
 -
 -	bp = &term.line[n][0];
 -	end = &bp[MIN(tlinelen(n), term.col) - 1];
 -	if (bp != end || bp->u != ' ') {
 -		for ( ; bp <= end; ++bp)
 -			tprinter(buf, utf8encode(bp->u, buf));
 -	}
 -	tprinter("\n", 1);
 +	char str[(term.col + 1) * UTF_SIZ];
 +  tprinter(str, tgetline(str, &term.line[n][0]));
  }
  
  void
 @@ -2252,7 +2481,7 @@ eschandle(uchar ascii)
  		return 0;
  	case 'D': /* IND -- Linefeed */
  		if (term.c.y == term.bot) {
 -			tscrollup(term.top, 1);
 +			tscrollup(term.top, term.bot, 1, SCROLL_SAVEHIST);
  		} else {
  			tmoveto(term.c.x, term.c.y+1);
  		}
 @@ -2405,7 +2634,8 @@ check_control_code:
  		 */
  		return;
  	}
 -	if (selected(term.c.x, term.c.y))
 +	/* selected() takes relative coordinates */
 +	if (selected(term.c.x + term.scr, term.c.y + term.scr))
  		selclear();
  
  	gp = &term.line[term.c.y][term.c.x];
 @@ -2436,6 +2666,7 @@ check_control_code:
  	if (term.c.x+width < term.col) {
  		tmoveto(term.c.x+width, term.c.y);
  	} else {
 +		term.wrapcwidth[IS_SET(MODE_ALTSCREEN)] = width;
  		term.c.state |= CURSOR_WRAPNEXT;
  	}
  }
 @@ -2473,85 +2704,275 @@ twrite(const char *buf, int buflen, int show_ctrl)
  }
  
  void
 -tresize(int col, int row)
 +treflow(int col, int row)
  {
 -	int i;
 -	int minrow = MIN(row, term.row);
 -	int mincol = MIN(col, term.col);
 -	int *bp;
 -	TCursor c;
 -
 -	if (col < 1 || row < 1) {
 -		fprintf(stderr,
 -		        "tresize: error resizing to %dx%d\n", col, row);
 -		return;
 +	int i, j;
 +	int oce, nce, bot, scr;
 +	int ox = 0, oy = -term.histf, nx = 0, ny = -1, len;
 +	int cy = -1; /* proxy for new y coordinate of cursor */
 +	int nlines;
 +	Line *buf, line;
 +
 +	/* y coordinate of cursor line end */
 +	for (oce = term.c.y; oce < term.row - 1 &&
 +	                     tiswrapped(term.line[oce]); oce++);
 +
 +	nlines = term.histf + oce + 1;
 +	if (col < term.col) {
 +		/* each line can take this many lines after reflow */
 +		j = (term.col + col - 1) / col;
 +		nlines = j * nlines;
 +		if (nlines > HISTSIZE + RESIZEBUFFER + row) {
 +			nlines = HISTSIZE + RESIZEBUFFER + row;
 +			oy = -(nlines / j - oce - 1);
 +		}
  	}
 +	buf = xmalloc(nlines * sizeof(Line));
 +	do {
 +		if (!nx)
 +			buf[++ny] = xmalloc(col * sizeof(Glyph));
 +		if (!ox) {
 +			line = TLINEABS(oy);
 +			len = tlinelen(line);
 +		}
 +		if (oy == term.c.y) {
 +			if (!ox)
 +				len = MAX(len, term.c.x + 1);
 +			/* update cursor */
 +			if (cy < 0 && term.c.x - ox < col - nx) {
 +				term.c.x = nx + term.c.x - ox, cy = ny;
 +				UPDATEWRAPNEXT(0, col);
 +			}
 +		}
 +		/* get reflowed lines in buf */
 +		if (col - nx > len - ox) {
 +			memcpy(&buf[ny][nx], &line[ox], (len-ox) * sizeof(Glyph));
 +			nx += len - ox;
 +			if (len == 0 || !(line[len - 1].mode & ATTR_WRAP)) {
 +				for (j = nx; j < col; j++)
 +					tclearglyph(&buf[ny][j], 0);
 +				nx = 0;
 +			} else if (nx > 0) {
 +				buf[ny][nx - 1].mode &= ~ATTR_WRAP;
 +			}
 +			ox = 0, oy++;
 +		} else if (col - nx == len - ox) {
 +			memcpy(&buf[ny][nx], &line[ox], (col-nx) * sizeof(Glyph));
 +			ox = 0, oy++, nx = 0;
 +		} else/* if (col - nx < len - ox) */ {
 +			memcpy(&buf[ny][nx], &line[ox], (col-nx) * sizeof(Glyph));
 +    	ox += col - nx;
 +			buf[ny][col - 1].mode |= ATTR_WRAP;
 +			nx = 0;
 +		}
 +	} while (oy <= oce);
 +	if (nx)
 +		for (j = nx; j < col; j++)
 +			tclearglyph(&buf[ny][j], 0);
  
 -	/*
 -	 * slide screen to keep cursor where we expect it -
 -	 * tscrollup would work here, but we can optimize to
 -	 * memmove because we're freeing the earlier lines
 -	 */
 -	for (i = 0; i <= term.c.y - row; i++) {
 +	/* free extra lines */
 +	for (i = row; i < term.row; i++)
  		free(term.line[i]);
 -		free(term.alt[i]);
 +	/* resize to new height */
 +	term.line = xrealloc(term.line, row * sizeof(Line));
 +
 +	bot = MIN(ny, row - 1);
 +	scr = MAX(row - term.row, 0);
 +	/* update y coordinate of cursor line end */
 +	nce = MIN(oce + scr, bot);
 +	/* update cursor y coordinate */
 +	term.c.y = nce - (ny - cy);
 +	if (term.c.y < 0) {
 +		j = nce, nce = MIN(nce + -term.c.y, bot);
 +		term.c.y += nce - j;
 +		while (term.c.y < 0) {
 +			free(buf[ny--]);
 +			term.c.y++;
 +		}
  	}
 -	/* ensure that both src and dst are not NULL */
 -	if (i > 0) {
 -		memmove(term.line, term.line + i, row * sizeof(Line));
 -		memmove(term.alt, term.alt + i, row * sizeof(Line));
 +	/* allocate new rows */
 +	for (i = row - 1; i > nce; i--) {
 +		term.line[i] = xmalloc(col * sizeof(Glyph));
 +		for (j = 0; j < col; j++)
 +			tclearglyph(&term.line[i][j], 0);
  	}
 -	for (i += row; i < term.row; i++) {
 +	/* fill visible area */
 +	for (/*i = nce */; i >= term.row; i--, ny--)
 +		term.line[i] = buf[ny];
 +	for (/*i = term.row - 1 */; i >= 0; i--, ny--) {
  		free(term.line[i]);
 -		free(term.alt[i]);
 +		term.line[i] = buf[ny];
  	}
 +	/* fill lines in history buffer and update term.histf */
 +	for (/*i = -1 */; ny >= 0 && i >= -HISTSIZE; i--, ny--) {
 +		j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
 +		free(term.hist[j]);
 +		term.hist[j] = buf[ny];
 +	}
 +	term.histf = -i - 1;
 +	term.scr = MIN(term.scr, term.histf);
 +	/* resize rest of the history lines */
 +	for (/*i = -term.histf - 1 */; i >= -HISTSIZE; i--) {
 +		j = (term.histi + i + 1 + HISTSIZE) % HISTSIZE;
 +		term.hist[j] = xrealloc(term.hist[j], col * sizeof(Glyph));
 +	}
 +	free(buf);
 +}
  
 -	/* resize to new height */
 -	term.line = xrealloc(term.line, row * sizeof(Line));
 -	term.alt  = xrealloc(term.alt,  row * sizeof(Line));
 -	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
 -	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
 +void
 +rscrolldown(int n)
 +{
 +	int i;
 +	Line temp;
  
 -	/* resize each row to new width, zero-pad if needed */
 -	for (i = 0; i < minrow; i++) {
 -		term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
 -		term.alt[i]  = xrealloc(term.alt[i],  col * sizeof(Glyph));
 -	}
 +	/* can never be true as of now
 +	if (IS_SET(MODE_ALTSCREEN))
 +		return; */
  
 -	/* allocate any new rows */
 -	for (/* i = minrow */; i < row; i++) {
 -		term.line[i] = xmalloc(col * sizeof(Glyph));
 -		term.alt[i] = xmalloc(col * sizeof(Glyph));
 +	if ((n = MIN(n, term.histf)) <= 0)
 +		return;
 +
 +	for (i = term.c.y + n; i >= n; i--) {
 +		temp = term.line[i];
 +		term.line[i] = term.line[i-n];
 +		term.line[i-n] = temp;
  	}
 +	for (/*i = n - 1 */; i >= 0; i--) {
 +		temp = term.line[i];
 +		term.line[i] = term.hist[term.histi];
 +		term.hist[term.histi] = temp;
 +		term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
 +	}
 +	term.c.y += n;
 +	term.histf -= n;
 +	if ((i = term.scr - n) >= 0) {
 +		term.scr = i;
 +	} else {
 +		term.scr = 0;
 +		if (sel.ob.x != -1 && !sel.alt)
 +			selmove(-i);
 +	}
 +}
 +
 +void
 +tresize(int col, int row)
 +{
 +	int *bp;
 +
 +	/* col and row are always MAX(_, 1)
 +	if (col < 1 || row < 1) {
 +		fprintf(stderr, "tresize: error resizing to %dx%d\n", col, row);
 +		return;
 +	} */
 +
 +	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
 +	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
  	if (col > term.col) {
  		bp = term.tabs + term.col;
 -
  		memset(bp, 0, sizeof(*term.tabs) * (col - term.col));
  		while (--bp > term.tabs && !*bp)
  			/* nothing */ ;
  		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
  			*bp = 1;
  	}
 -	/* update terminal size */
 -	term.col = col;
 -	term.row = row;
 -	/* reset scrolling region */
 -	tsetscroll(0, row-1);
 -	/* make use of the LIMIT in tmoveto */
 -	tmoveto(term.c.x, term.c.y);
 -	/* Clearing both screens (it makes dirty all lines) */
 -	c = term.c;
 -	for (i = 0; i < 2; i++) {
 -		if (mincol < col && 0 < minrow) {
 -			tclearregion(mincol, 0, col - 1, minrow - 1);
 +
 +	if (IS_SET(MODE_ALTSCREEN))
 +		tresizealt(col, row);
 +	else
 +		tresizedef(col, row);
 +}
 +
 +void
 +tresizedef(int col, int row)
 +{
 +	int i, j;
 +
 +	/* return if dimensions haven't changed */
 +	if (term.col == col && term.row == row) {
 +		tfulldirt();
 +		return;
 +	}
 +	if (col != term.col) {
 +		if (!sel.alt)
 +			selremove();
 +		treflow(col, row);
 +	} else {
 +		/* slide screen up if otherwise cursor would get out of the screen */
 +		if (term.c.y >= row) {
 +			tscrollup(0, term.row - 1, term.c.y - row + 1, SCROLL_RESIZE);
 +			term.c.y = row - 1;
  		}
 -		if (0 < col && minrow < row) {
 -			tclearregion(0, minrow, col - 1, row - 1);
 +		for (i = row; i < term.row; i++)
 +			free(term.line[i]);
 +
 +		/* resize to new height */
 +		term.line = xrealloc(term.line, row * sizeof(Line));
 +		/* allocate any new rows */
 +		for (i = term.row; i < row; i++) {
 +			term.line[i] = xmalloc(col * sizeof(Glyph));
 +			for (j = 0; j < col; j++)
 +				tclearglyph(&term.line[i][j], 0);
  		}
 -		tswapscreen();
 -		tcursor(CURSOR_LOAD);
 +		/* scroll down as much as height has increased */
 +		rscrolldown(row - term.row);
 +	}
 +	/* update terminal size */
 +	term.col = col, term.row = row;
 +	/* reset scrolling region */
 +	term.top = 0, term.bot = row - 1;
 +	/* dirty all lines */
 +	tfulldirt();
 +}
 +
 +void
 +tresizealt(int col, int row)
 +{
 +	int i, j;
 +
 +	/* return if dimensions haven't changed */
 +	if (term.col == col && term.row == row) {
 +		tfulldirt();
 +		return;
  	}
 -	term.c = c;
 +	if (sel.alt)
 +		selremove();
 +	/* slide screen up if otherwise cursor would get out of the screen */
 +	for (i = 0; i <= term.c.y - row; i++)
 +		free(term.line[i]);
 +	if (i > 0) {
 +		/* ensure that both src and dst are not NULL */
 +		memmove(term.line, term.line + i, row * sizeof(Line));
 +		term.c.y = row - 1;
 +	}
 +	for (i += row; i < term.row; i++)
 +		free(term.line[i]);
 +	/* resize to new height */
 +	term.line = xrealloc(term.line, row * sizeof(Line));
 +	/* resize to new width */
 +	for (i = 0; i < MIN(row, term.row); i++) {
 +		term.line[i] = xrealloc(term.line[i], col * sizeof(Glyph));
 +		for (j = term.col; j < col; j++)
 +			tclearglyph(&term.line[i][j], 0);
 +	}
 +	/* allocate any new rows */
 +	for (/*i = MIN(row, term.row) */; i < row; i++) {
 +		term.line[i] = xmalloc(col * sizeof(Glyph));
 +		for (j = 0; j < col; j++)
 +			tclearglyph(&term.line[i][j], 0);
 +	}
 +	/* update cursor */
 +	if (term.c.x >= col) {
 +		term.c.state &= ~CURSOR_WRAPNEXT;
 +		term.c.x = col - 1;
 +	} else {
 +		UPDATEWRAPNEXT(1, col);
 +	}
 +	/* update terminal size */
 +	term.col = col, term.row = row;
 +	/* reset scrolling region */
 +	term.top = 0, term.bot = row - 1;
 +	/* dirty all lines */
 +	tfulldirt();
  }
  
  void
 @@ -2570,7 +2991,7 @@ drawregion(int x1, int y1, int x2, int y2)
  			continue;
  
  		term.dirty[y] = 0;
 -		xdrawline(term.line[y], x1, y, x2);
 +		xdrawline(TLINE(y), x1, y, x2);
  	}
  }
  
 diff --git a/st.h b/st.h
 index fa2eddf..5b3ea8c 100644
 --- a/st.h
 +++ b/st.h
 @@ -21,18 +21,20 @@
  #define IS_TRUECOL(x)		(1 << 24 & (x))
  
  enum glyph_attribute {
 -	ATTR_NULL       = 0,
 -	ATTR_BOLD       = 1 << 0,
 -	ATTR_FAINT      = 1 << 1,
 -	ATTR_ITALIC     = 1 << 2,
 -	ATTR_UNDERLINE  = 1 << 3,
 -	ATTR_BLINK      = 1 << 4,
 -	ATTR_REVERSE    = 1 << 5,
 -	ATTR_INVISIBLE  = 1 << 6,
 -	ATTR_STRUCK     = 1 << 7,
 -	ATTR_WRAP       = 1 << 8,
 -	ATTR_WIDE       = 1 << 9,
 -	ATTR_WDUMMY     = 1 << 10,
 +  ATTR_NULL       = 0,
 +  ATTR_SET        = 1 << 0,
 +	ATTR_BOLD       = 1 << 1,
 +	ATTR_FAINT      = 1 << 2,
 +	ATTR_ITALIC     = 1 << 3,
 +	ATTR_UNDERLINE  = 1 << 4,
 +	ATTR_BLINK      = 1 << 5,
 +	ATTR_REVERSE    = 1 << 6,
 +	ATTR_INVISIBLE  = 1 << 7,
 +	ATTR_STRUCK     = 1 << 8,
 +	ATTR_WRAP       = 1 << 9,
 +	ATTR_WIDE       = 1 << 10,
 +	ATTR_WDUMMY     = 1 << 11,
 +	ATTR_SELECTED   = 1 << 12,
  	ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
  };
  
 @@ -81,6 +83,8 @@ void die(const char *, ...);
  void redraw(void);
  void draw(void);
  
 +void kscrolldown(const Arg *);
 +void kscrollup(const Arg *);
  void printscreen(const Arg *);
  void printsel(const Arg *);
  void sendbreak(const Arg *);
 @@ -88,6 +92,7 @@ void toggleprinter(const Arg *);
  
  int tattrset(int);
  void tnew(int, int);
 +int tisaltscreen(void);
  void tresize(int, int);
  void tsetdirtattr(int);
  void ttyhangup(void);