Revert "appy scrollback-ringbuffer patch"

This reverts commit 75110c3cdea1cade7a9b097806cae1a32f8a5e8a.

5 files changed, 122 insertions, 979 deletions

diff --git a/config.def.h b/config.def.h
index 1660264..5fad72a 100644
--- a/config.def.h
+++ b/config.def.h
@@ -228,8 +228,6 @@ static Shortcut shortcuts[] = {
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
 	{ MODKEY,               XK_l,           copyurl,        {.i =  0} },
-        { ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
-        { ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
 };
 
 /*
diff --git a/patches/st-scrollback-ringbuffer-0.8.5.diff b/patches/st-scrollback-ringbuffer-0.8.5.diff
deleted file mode 100644
index 7c060c5..0000000
--- a/patches/st-scrollback-ringbuffer-0.8.5.diff
+++ /dev/null
@@ -1,730 +0,0 @@
-commit 0663bdf11a409961da5b1120741a69814da8ce65
-Author: Timo Röhling <timo@gaussglocke.de>
-Date:   Tue Nov 23 19:45:33 2021 +0100
-
-    Terminal scrollback with ring buffer
-    
-    This patch adds a ring buffer for scrollback to the terminal.  The
-    advantage of using a ring buffer is that the common case, scrolling with
-    no static screen content, can be achieved very efficiently by
-    incrementing and decrementing the starting line (modulo buffer size).
-    
-    The scrollback buffer is limited to HISTSIZE lines in order to bound
-    memory usage. As the lines are allocated on demand, it is possible to
-    implement unlimited scrollback with few changes.  If the terminal is
-    reset, the scroll back buffer is reset, too.
-
-diff --git a/config.def.h b/config.def.h
-index 91ab8ca..e3b469b 100644
---- a/config.def.h
-+++ b/config.def.h
-@@ -201,6 +201,8 @@ static Shortcut shortcuts[] = {
- 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
- 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
- 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
-+	{ ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
-+	{ ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
- };
- 
- /*
-diff --git a/st.c b/st.c
-index 51049ba..f9e24ba 100644
---- a/st.c
-+++ b/st.c
-@@ -43,6 +43,10 @@
- #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
- #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
- 
-+#define TSCREEN term.screen[IS_SET(MODE_ALTSCREEN)]
-+#define TLINEOFFSET(y) (((y) + TSCREEN.cur - TSCREEN.off + TSCREEN.size) % TSCREEN.size)
-+#define TLINE(y) (TSCREEN.buffer[TLINEOFFSET(y)])
-+
- enum term_mode {
- 	MODE_WRAP        = 1 << 0,
- 	MODE_INSERT      = 1 << 1,
-@@ -109,12 +113,21 @@ typedef struct {
- 	int alt;
- } Selection;
- 
-+/* Screen lines */
-+typedef struct {
-+	Line* buffer;  /* ring buffer */
-+	int size;      /* size of buffer */
-+	int cur;       /* start of active screen */
-+	int off;       /* scrollback line offset */
-+	TCursor sc;    /* saved cursor */
-+} LineBuffer;
-+
- /* Internal representation of the screen */
- typedef struct {
- 	int row;      /* nb row */
- 	int col;      /* nb col */
--	Line *line;   /* screen */
--	Line *alt;    /* alternate screen */
-+	LineBuffer screen[2]; /* screen and alternate screen */
-+	int linelen;  /* allocated line length */
- 	int *dirty;   /* dirtyness of lines */
- 	TCursor c;    /* cursor */
- 	int ocx;      /* old cursor col */
-@@ -202,6 +215,8 @@ static void tdeftran(char);
- static void tstrsequence(uchar);
- 
- static void drawregion(int, int, int, int);
-+static void clearline(Line, Glyph, int, int);
-+static Line ensureline(Line);
- 
- static void selnormalize(void);
- static void selscroll(int, int);
-@@ -415,11 +430,12 @@ int
- tlinelen(int y)
- {
- 	int i = term.col;
-+	Line line = TLINE(y);
- 
--	if (term.line[y][i - 1].mode & ATTR_WRAP)
-+	if (line[i - 1].mode & ATTR_WRAP)
- 		return i;
- 
--	while (i > 0 && term.line[y][i - 1].u == ' ')
-+	while (i > 0 && line[i - 1].u == ' ')
- 		--i;
- 
- 	return i;
-@@ -528,7 +544,7 @@ selsnap(int *x, int *y, int direction)
- 		 * 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;
-@@ -543,14 +559,14 @@ selsnap(int *x, int *y, int direction)
- 					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))
- 				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)))
-@@ -571,14 +587,14 @@ 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
-+				if (!(TLINE(*y-1)[term.col-1].mode
- 						& ATTR_WRAP)) {
- 					break;
- 				}
- 			}
- 		} else if (direction > 0) {
- 			for (; *y < term.row-1; *y += direction) {
--				if (!(term.line[*y][term.col-1].mode
-+				if (!(TLINE(*y)[term.col-1].mode
- 						& ATTR_WRAP)) {
- 					break;
- 				}
-@@ -609,13 +625,13 @@ getsel(void)
- 		}
- 
- 		if (sel.type == SEL_RECTANGULAR) {
--			gp = &term.line[y][sel.nb.x];
-+			gp = &TLINE(y)[sel.nb.x];
- 			lastx = sel.ne.x;
- 		} else {
--			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
-+			gp = &TLINE(y)[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)];
-+		last = &TLINE(y)[MIN(lastx, linelen-1)];
- 		while (last >= gp && last->u == ' ')
- 			--last;
- 
-@@ -956,12 +972,15 @@ int
- tattrset(int attr)
- {
- 	int i, j;
-+	int y = TLINEOFFSET(0);
- 
- 	for (i = 0; i < term.row-1; i++) {
-+		Line line = TSCREEN.buffer[y];
- 		for (j = 0; j < term.col-1; j++) {
--			if (term.line[i][j].mode & attr)
-+			if (line[j].mode & attr)
- 				return 1;
- 		}
-+		y = (y+1) % TSCREEN.size;
- 	}
- 
- 	return 0;
-@@ -983,14 +1002,17 @@ void
- tsetdirtattr(int attr)
- {
- 	int i, j;
-+	int y = TLINEOFFSET(0);
- 
- 	for (i = 0; i < term.row-1; i++) {
-+		Line line = TSCREEN.buffer[y];
- 		for (j = 0; j < term.col-1; j++) {
--			if (term.line[i][j].mode & attr) {
-+			if (line[j].mode & attr) {
- 				tsetdirt(i, i);
- 				break;
- 			}
- 		}
-+		y = (y+1) % TSCREEN.size;
- 	}
- }
- 
-@@ -1003,27 +1025,19 @@ tfulldirt(void)
- void
- tcursor(int mode)
- {
--	static TCursor c[2];
--	int alt = IS_SET(MODE_ALTSCREEN);
--
- 	if (mode == CURSOR_SAVE) {
--		c[alt] = term.c;
-+		TSCREEN.sc = term.c;
- 	} else if (mode == CURSOR_LOAD) {
--		term.c = c[alt];
--		tmoveto(c[alt].x, c[alt].y);
-+		term.c = TSCREEN.sc;
-+		tmoveto(term.c.x, term.c.y);
- 	}
- }
- 
- void
- treset(void)
- {
--	uint i;
--
--	term.c = (TCursor){{
--		.mode = ATTR_NULL,
--		.fg = defaultfg,
--		.bg = defaultbg
--	}, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
-+	int i, j;
-+	Glyph g = (Glyph){ .fg = defaultfg, .bg = defaultbg};
- 
- 	memset(term.tabs, 0, term.col * sizeof(*term.tabs));
- 	for (i = tabspaces; i < term.col; i += tabspaces)
-@@ -1035,17 +1049,37 @@ treset(void)
- 	term.charset = 0;
- 
- 	for (i = 0; i < 2; i++) {
--		tmoveto(0, 0);
--		tcursor(CURSOR_SAVE);
--		tclearregion(0, 0, term.col-1, term.row-1);
--		tswapscreen();
-+		term.screen[i].sc = (TCursor){{
-+			.fg = defaultfg,
-+			.bg = defaultbg
-+		}};
-+		term.screen[i].cur = 0;
-+		term.screen[i].off = 0;
-+		for (j = 0; j < term.row; ++j) {
-+			if (term.col != term.linelen)
-+				term.screen[i].buffer[j] = xrealloc(term.screen[i].buffer[j], term.col * sizeof(Glyph));
-+			clearline(term.screen[i].buffer[j], g, 0, term.col);
-+		}
-+		for (j = term.row; j < term.screen[i].size; ++j) {
-+			free(term.screen[i].buffer[j]);
-+			term.screen[i].buffer[j] = NULL;
-+		}
- 	}
-+	tcursor(CURSOR_LOAD);
-+	term.linelen = term.col;
-+	tfulldirt();
- }
- 
- void
- tnew(int col, int row)
- {
--	term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
-+	int i;
-+	term = (Term){};
-+	term.screen[0].buffer = xmalloc(HISTSIZE * sizeof(Line));
-+	term.screen[0].size = HISTSIZE;
-+	term.screen[1].buffer = NULL;
-+	for (i = 0; i < HISTSIZE; ++i) term.screen[0].buffer[i] = NULL;
-+
- 	tresize(col, row);
- 	treset();
- }
-@@ -1053,14 +1087,42 @@ tnew(int col, int row)
- void
- tswapscreen(void)
- {
--	Line *tmp = term.line;
--
--	term.line = term.alt;
--	term.alt = tmp;
- 	term.mode ^= MODE_ALTSCREEN;
- 	tfulldirt();
- }
- 
-+void
-+kscrollup(const Arg *a)
-+{
-+	int n = a->i;
-+
-+	if (IS_SET(MODE_ALTSCREEN))
-+		return;
-+
-+	if (n < 0) n = (-n) * term.row;
-+	if (n > TSCREEN.size - term.row - TSCREEN.off) n = TSCREEN.size - term.row - TSCREEN.off;
-+	while (!TLINE(-n)) --n;
-+	TSCREEN.off += n;
-+	selscroll(0, n);
-+	tfulldirt();
-+}
-+
-+void
-+kscrolldown(const Arg *a)
-+{
-+
-+	int n = a->i;
-+
-+	if (IS_SET(MODE_ALTSCREEN))
-+		return;
-+
-+	if (n < 0) n = (-n) * term.row;
-+	if (n > TSCREEN.off) n = TSCREEN.off;
-+	TSCREEN.off -= n;
-+	selscroll(0, -n);
-+	tfulldirt();
-+}
-+
- void
- tscrolldown(int orig, int n)
- {
-@@ -1069,15 +1131,29 @@ tscrolldown(int orig, int n)
- 
- 	LIMIT(n, 0, term.bot-orig+1);
- 
--	tsetdirt(orig, term.bot-n);
--	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
-+	/* Ensure that lines are allocated */
-+	for (i = -n; i < 0; i++) {
-+		TLINE(i) = ensureline(TLINE(i));
-+	}
- 
--	for (i = term.bot; i >= orig+n; i--) {
--		temp = term.line[i];
--		term.line[i] = term.line[i-n];
--		term.line[i-n] = temp;
-+	/* Shift non-scrolling areas in ring buffer */
-+	for (i = term.bot+1; i < term.row; i++) {
-+		temp = TLINE(i);
-+		TLINE(i) = TLINE(i-n);
-+		TLINE(i-n) = temp;
-+	}
-+	for (i = 0; i < orig; i++) {
-+		temp = TLINE(i);
-+		TLINE(i) = TLINE(i-n);
-+		TLINE(i-n) = temp;
- 	}
- 
-+	/* Scroll buffer */
-+	TSCREEN.cur = (TSCREEN.cur + TSCREEN.size - n) % TSCREEN.size;
-+	/* Clear lines that have entered the view */
-+	tclearregion(0, orig, term.linelen-1, orig+n-1);
-+	/* Redraw portion of the screen that has scrolled */
-+	tsetdirt(orig+n-1, term.bot);
- 	selscroll(orig, n);
- }
- 
-@@ -1089,15 +1165,29 @@ tscrollup(int orig, int n)
- 
- 	LIMIT(n, 0, term.bot-orig+1);
- 
--	tclearregion(0, orig, term.col-1, orig+n-1);
--	tsetdirt(orig+n, term.bot);
-+	/* Ensure that lines are allocated */
-+	for (i = term.row; i < term.row + n; i++) {
-+		TLINE(i) = ensureline(TLINE(i));
-+	}
- 
--	for (i = orig; i <= term.bot-n; i++) {
--		temp = term.line[i];
--		term.line[i] = term.line[i+n];
--		term.line[i+n] = temp;
-+	/* Shift non-scrolling areas in ring buffer */
-+	for (i = orig-1; i >= 0; i--) {
-+		temp = TLINE(i);
-+		TLINE(i) = TLINE(i+n);
-+		TLINE(i+n) = temp;
-+	}
-+	for (i = term.row-1; i >term.bot; i--) {
-+		temp = TLINE(i);
-+		TLINE(i) = TLINE(i+n);
-+		TLINE(i+n) = temp;
- 	}
- 
-+	/* Scroll buffer */
-+	TSCREEN.cur = (TSCREEN.cur + n) % TSCREEN.size;
-+	/* Clear lines that have entered the view */
-+	tclearregion(0, term.bot-n+1, term.linelen-1, term.bot);
-+	/* Redraw portion of the screen that has scrolled */
-+	tsetdirt(orig, term.bot-n+1);
- 	selscroll(orig, -n);
- }
- 
-@@ -1201,6 +1291,7 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
- 		"⎻", "─", "⎼", "⎽", "├", "┤", "┴", "┬", /* p - w */
- 		"│", "≤", "≥", "π", "≠", "£", "·", /* x - ~ */
- 	};
-+	Line line = TLINE(y);
- 
- 	/*
- 	 * The table is proudly stolen from rxvt.
-@@ -1209,25 +1300,25 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
- 	   BETWEEN(u, 0x41, 0x7e) && vt100_0[u - 0x41])
- 		utf8decode(vt100_0[u - 0x41], &u, UTF_SIZ);
- 
--	if (term.line[y][x].mode & ATTR_WIDE) {
-+	if (line[x].mode & ATTR_WIDE) {
- 		if (x+1 < term.col) {
--			term.line[y][x+1].u = ' ';
--			term.line[y][x+1].mode &= ~ATTR_WDUMMY;
-+			line[x+1].u = ' ';
-+			line[x+1].mode &= ~ATTR_WDUMMY;
- 		}
--	} else if (term.line[y][x].mode & ATTR_WDUMMY) {
--		term.line[y][x-1].u = ' ';
--		term.line[y][x-1].mode &= ~ATTR_WIDE;
-+	} else if (line[x].mode & ATTR_WDUMMY) {
-+		line[x-1].u = ' ';
-+		line[x-1].mode &= ~ATTR_WIDE;
- 	}
- 
- 	term.dirty[y] = 1;
--	term.line[y][x] = *attr;
--	term.line[y][x].u = u;
-+	line[x] = *attr;
-+	line[x].u = u;
- }
- 
- void
- tclearregion(int x1, int y1, int x2, int y2)
- {
--	int x, y, temp;
-+	int x, y, L, S, temp;
- 	Glyph *gp;
- 
- 	if (x1 > x2)
-@@ -1235,15 +1326,16 @@ tclearregion(int x1, int y1, int x2, int y2)
- 	if (y1 > y2)
- 		temp = y1, y1 = y2, y2 = temp;
- 
--	LIMIT(x1, 0, term.col-1);
--	LIMIT(x2, 0, term.col-1);
-+	LIMIT(x1, 0, term.linelen-1);
-+	LIMIT(x2, 0, term.linelen-1);
- 	LIMIT(y1, 0, term.row-1);
- 	LIMIT(y2, 0, term.row-1);
- 
-+	L = TLINEOFFSET(y1);
- 	for (y = y1; y <= y2; y++) {
- 		term.dirty[y] = 1;
- 		for (x = x1; x <= x2; x++) {
--			gp = &term.line[y][x];
-+			gp = &TSCREEN.buffer[L][x];
- 			if (selected(x, y))
- 				selclear();
- 			gp->fg = term.c.attr.fg;
-@@ -1251,6 +1343,7 @@ tclearregion(int x1, int y1, int x2, int y2)
- 			gp->mode = 0;
- 			gp->u = ' ';
- 		}
-+		L = (L + 1) % TSCREEN.size;
- 	}
- }
- 
-@@ -1265,7 +1358,7 @@ tdeletechar(int n)
- 	dst = term.c.x;
- 	src = term.c.x + n;
- 	size = term.col - src;
--	line = term.line[term.c.y];
-+	line = TLINE(term.c.y);
- 
- 	memmove(&line[dst], &line[src], size * sizeof(Glyph));
- 	tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
-@@ -1282,7 +1375,7 @@ tinsertblank(int n)
- 	dst = term.c.x + n;
- 	src = term.c.x;
- 	size = term.col - dst;
--	line = term.line[term.c.y];
-+	line = TLINE(term.c.y);
- 
- 	memmove(&line[dst], &line[src], size * sizeof(Glyph));
- 	tclearregion(src, term.c.y, dst - 1, term.c.y);
-@@ -2103,7 +2196,7 @@ tdumpline(int n)
- 	char buf[UTF_SIZ];
- 	const Glyph *bp, *end;
- 
--	bp = &term.line[n][0];
-+	bp = &TLINE(n)[0];
- 	end = &bp[MIN(tlinelen(n), term.col) - 1];
- 	if (bp != end || bp->u != ' ') {
- 		for ( ; bp <= end; ++bp)
-@@ -2486,11 +2579,11 @@ check_control_code:
- 	if (selected(term.c.x, term.c.y))
- 		selclear();
- 
--	gp = &term.line[term.c.y][term.c.x];
-+	gp = &TLINE(term.c.y)[term.c.x];
- 	if (IS_SET(MODE_WRAP) && (term.c.state & CURSOR_WRAPNEXT)) {
- 		gp->mode |= ATTR_WRAP;
- 		tnewline(1);
--		gp = &term.line[term.c.y][term.c.x];
-+		gp = &TLINE(term.c.y)[term.c.x];
- 	}
- 
- 	if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
-@@ -2498,7 +2591,7 @@ check_control_code:
- 
- 	if (term.c.x+width > term.col) {
- 		tnewline(1);
--		gp = &term.line[term.c.y][term.c.x];
-+		gp = &TLINE(term.c.y)[term.c.x];
- 	}
- 
- 	tsetchar(u, &term.c.attr, term.c.x, term.c.y);
-@@ -2529,6 +2622,11 @@ twrite(const char *buf, int buflen, int show_ctrl)
- 	Rune u;
- 	int n;
- 
-+	if (TSCREEN.off) {
-+		TSCREEN.off = 0;
-+		tfulldirt();
-+	}
-+
- 	for (n = 0; n < buflen; n += charsize) {
- 		if (IS_SET(MODE_UTF8)) {
- 			/* process a complete utf8 char */
-@@ -2555,56 +2653,85 @@ twrite(const char *buf, int buflen, int show_ctrl)
- }
- 
- void
--tresize(int col, int row)
-+clearline(Line line, Glyph g, int x, int xend)
- {
- 	int i;
-+	g.mode = 0;
-+	g.u = ' ';
-+	for (i = x; i < xend; ++i) {
-+		line[i] = g;
-+	}
-+}
-+
-+Line
-+ensureline(Line line)
-+{
-+	if (!line) {
-+		line = xmalloc(term.linelen * sizeof(Glyph));
-+	}
-+	return line;
-+}
-+
-+void
-+tresize(int col, int row)
-+{
-+	int i, j;
- 	int minrow = MIN(row, term.row);
- 	int mincol = MIN(col, term.col);
-+	int linelen = MAX(col, term.linelen);
- 	int *bp;
--	TCursor c;
- 
--	if (col < 1 || row < 1) {
-+	if (col < 1 || row < 1 || row > HISTSIZE) {
- 		fprintf(stderr,
- 		        "tresize: error resizing to %dx%d\n", col, row);
- 		return;
- 	}
- 
--	/*
--	 * 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(term.line[i]);
--		free(term.alt[i]);
-+	/* Shift buffer to keep the cursor where we expect it */
-+	if (row <= term.c.y) {
-+		term.screen[0].cur = (term.screen[0].cur - row + term.c.y + 1) % term.screen[0].size;
-+	}
-+
-+	/* Resize and clear line buffers as needed */
-+	if (linelen > term.linelen) {
-+		for (i = 0; i < term.screen[0].size; ++i) {
-+			if (term.screen[0].buffer[i]) {
-+				term.screen[0].buffer[i] = xrealloc(term.screen[0].buffer[i], linelen * sizeof(Glyph));
-+				clearline(term.screen[0].buffer[i], term.c.attr, term.linelen, linelen);
-+			}
-+		}
-+		for (i = 0; i < minrow; ++i) {
-+			term.screen[1].buffer[i] = xrealloc(term.screen[1].buffer[i], linelen * sizeof(Glyph));
-+			clearline(term.screen[1].buffer[i], term.c.attr, term.linelen, linelen);
-+		}
- 	}
--	/* 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 all visible lines for regular line buffer */
-+	for (j = term.screen[0].cur, i = 0; i < row; ++i, j = (j + 1) % term.screen[0].size)
-+	{
-+		if (!term.screen[0].buffer[j]) {
-+			term.screen[0].buffer[j] = xmalloc(linelen * sizeof(Glyph));
-+		}
-+		if (i >= term.row) {
-+			clearline(term.screen[0].buffer[j], term.c.attr, 0, linelen);
-+		}
- 	}
--	for (i += row; i < term.row; i++) {
--		free(term.line[i]);
--		free(term.alt[i]);
-+	/* Resize alt screen */
-+	term.screen[1].cur = 0;
-+	term.screen[1].size = row;
-+	for (i = row; i < term.row; ++i) {
-+		free(term.screen[1].buffer[i]);
-+	}
-+	term.screen[1].buffer = xrealloc(term.screen[1].buffer, row * sizeof(Line));
-+	for (i = term.row; i < row; ++i) {
-+		term.screen[1].buffer[i] = xmalloc(linelen * sizeof(Glyph));
-+		clearline(term.screen[1].buffer[i], term.c.attr, 0, linelen);
- 	}
- 
- 	/* 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));
- 
--	/* 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));
--	}
--
--	/* allocate any new rows */
--	for (/* i = minrow */; i < row; i++) {
--		term.line[i] = xmalloc(col * sizeof(Glyph));
--		term.alt[i] = xmalloc(col * sizeof(Glyph));
--	}
-+	/* fix tabstops */
- 	if (col > term.col) {
- 		bp = term.tabs + term.col;
- 
-@@ -2614,26 +2741,16 @@ tresize(int col, int row)
- 		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
- 			*bp = 1;
- 	}
-+
- 	/* update terminal size */
- 	term.col = col;
- 	term.row = row;
-+	term.linelen = linelen;
- 	/* 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 (0 < col && minrow < row) {
--			tclearregion(0, minrow, col - 1, row - 1);
--		}
--		tswapscreen();
--		tcursor(CURSOR_LOAD);
--	}
--	term.c = c;
-+	tfulldirt();
- }
- 
- void
-@@ -2645,14 +2762,15 @@ resettitle(void)
- void
- drawregion(int x1, int y1, int x2, int y2)
- {
--	int y;
-+	int y, L;
- 
-+	L = TLINEOFFSET(y1);
- 	for (y = y1; y < y2; y++) {
--		if (!term.dirty[y])
--			continue;
--
--		term.dirty[y] = 0;
--		xdrawline(term.line[y], x1, y, x2);
-+		if (term.dirty[y]) {
-+			term.dirty[y] = 0;
-+			xdrawline(TSCREEN.buffer[L], x1, y, x2);
-+		}
-+		L = (L + 1) % TSCREEN.size;
- 	}
- }
- 
-@@ -2667,14 +2785,15 @@ draw(void)
- 	/* adjust cursor position */
- 	LIMIT(term.ocx, 0, term.col-1);
- 	LIMIT(term.ocy, 0, term.row-1);
--	if (term.line[term.ocy][term.ocx].mode & ATTR_WDUMMY)
-+	if (TLINE(term.ocy)[term.ocx].mode & ATTR_WDUMMY)
- 		term.ocx--;
--	if (term.line[term.c.y][cx].mode & ATTR_WDUMMY)
-+	if (TLINE(term.c.y)[cx].mode & ATTR_WDUMMY)
- 		cx--;
- 
- 	drawregion(0, 0, term.col, term.row);
--	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
--			term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
-+	if (TSCREEN.off == 0)
-+		xdrawcursor(cx, term.c.y, TLINE(term.c.y)[cx],
-+				term.ocx, term.ocy, TLINE(term.ocy)[term.ocx]);
- 	term.ocx = cx;
- 	term.ocy = term.c.y;
- 	xfinishdraw();
-diff --git a/st.h b/st.h
-index 519b9bd..b48e810 100644
---- a/st.h
-+++ b/st.h
-@@ -19,6 +19,7 @@
- 
- #define TRUECOLOR(r,g,b)	(1 << 24 | (r) << 16 | (g) << 8 | (b))
- #define IS_TRUECOL(x)		(1 << 24 & (x))
-+#define HISTSIZE            2000
- 
- enum glyph_attribute {
- 	ATTR_NULL       = 0,
-diff --git a/x.c b/x.c
-index 8a16faa..1bb5853 100644
---- a/x.c
-+++ b/x.c
-@@ -59,6 +59,8 @@ static void zoom(const Arg *);
- static void zoomabs(const Arg *);
- static void zoomreset(const Arg *);
- static void ttysend(const Arg *);
-+void kscrollup(const Arg *);
-+void kscrolldown(const Arg *);
- 
- /* config.h for applying patches and the configuration. */
- #include "config.h"
diff --git a/st.c b/st.c
index 62a9944..34347ce 100644
--- a/st.c
+++ b/st.c
@@ -43,10 +43,6 @@
 #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
 #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
 
-#define TSCREEN term.screen[IS_SET(MODE_ALTSCREEN)]
-#define TLINEOFFSET(y) (((y) + TSCREEN.cur - TSCREEN.off + TSCREEN.size) % TSCREEN.size)
-#define TLINE(y) (TSCREEN.buffer[TLINEOFFSET(y)])
-
 enum term_mode {
 	MODE_WRAP        = 1 << 0,
 	MODE_INSERT      = 1 << 1,
@@ -113,21 +109,12 @@ typedef struct {
 	int alt;
 } Selection;
 
-/* Screen lines */
-typedef struct {
-	Line* buffer;  /* ring buffer */
-	int size;      /* size of buffer */
-	int cur;       /* start of active screen */
-	int off;       /* scrollback line offset */
-	TCursor sc;    /* saved cursor */
-} LineBuffer;
-
 /* Internal representation of the screen */
 typedef struct {
 	int row;      /* nb row */
 	int col;      /* nb col */
-	LineBuffer screen[2]; /* screen and alternate screen */
-	int linelen;  /* allocated line length */
+	Line *line;   /* screen */
+	Line *alt;    /* alternate screen */
 	int *dirty;   /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int ocx;      /* old cursor col */
@@ -221,8 +208,6 @@ static void tstrsequence(uchar);
 static int daddch(URLdfa *, char);
 
 static void drawregion(int, int, int, int);
-static void clearline(Line, Glyph, int, int);
-static Line ensureline(Line);
 
 static void selnormalize(void);
 static void selscroll(int, int);
@@ -428,12 +413,11 @@ int
 tlinelen(int y)
 {
 	int i = term.col;
-	Line line = TLINE(y);
 
-	if (line[i - 1].mode & ATTR_WRAP)
+	if (term.line[y][i - 1].mode & ATTR_WRAP)
 		return i;
 
-	while (i > 0 && line[i - 1].u == ' ')
+	while (i > 0 && term.line[y][i - 1].u == ' ')
 		--i;
 
 	return i;
@@ -542,7 +526,7 @@ selsnap(int *x, int *y, int direction)
 		 * Snap around if the word wraps around at the end or
 		 * beginning of a line.
 		 */
-		prevgp = &TLINE(*y)[*x];
+		prevgp = &term.line[*y][*x];
 		prevdelim = ISDELIM(prevgp->u);
 		for (;;) {
 			newx = *x + direction;
@@ -557,14 +541,14 @@ selsnap(int *x, int *y, int direction)
 					yt = *y, xt = *x;
 				else
 					yt = newy, xt = newx;
-				if (!(TLINE(yt)[xt].mode & ATTR_WRAP))
+				if (!(term.line[yt][xt].mode & ATTR_WRAP))
 					break;
 			}
 
 			if (newx >= tlinelen(newy))
 				break;
 
-			gp = &TLINE(newy)[newx];
+			gp = &term.line[newy][newx];
 			delim = ISDELIM(gp->u);
 			if (!(gp->mode & ATTR_WDUMMY) && (delim != prevdelim
 					|| (delim && gp->u != prevgp->u)))
@@ -585,14 +569,14 @@ selsnap(int *x, int *y, int direction)
 		*x = (direction < 0) ? 0 : term.col - 1;
 		if (direction < 0) {
 			for (; *y > 0; *y += direction) {
-				if (!(TLINE(*y-1)[term.col-1].mode
+				if (!(term.line[*y-1][term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
 			}
 		} else if (direction > 0) {
 			for (; *y < term.row-1; *y += direction) {
-				if (!(TLINE(*y)[term.col-1].mode
+				if (!(term.line[*y][term.col-1].mode
 						& ATTR_WRAP)) {
 					break;
 				}
@@ -623,13 +607,13 @@ getsel(void)
 		}
 
 		if (sel.type == SEL_RECTANGULAR) {
-			gp = &TLINE(y)[sel.nb.x];
+			gp = &term.line[y][sel.nb.x];
 			lastx = sel.ne.x;
 		} else {
-			gp = &TLINE(y)[sel.nb.y == y ? sel.nb.x : 0];
+			gp = &term.line[y][sel.nb.y == y ? sel.nb.x : 0];
 			lastx = (sel.ne.y == y) ? sel.ne.x : term.col-1;
 		}
-		last = &TLINE(y)[MIN(lastx, linelen-1)];
+		last = &term.line[y][MIN(lastx, linelen-1)];
 		while (last >= gp && last->u == ' ')
 			--last;
 
@@ -970,15 +954,12 @@ int
 tattrset(int attr)
 {
 	int i, j;
-	int y = TLINEOFFSET(0);
 
 	for (i = 0; i < term.row-1; i++) {
-		Line line = TSCREEN.buffer[y];
 		for (j = 0; j < term.col-1; j++) {
-			if (line[j].mode & attr)
+			if (term.line[i][j].mode & attr)
 				return 1;
 		}
-		y = (y+1) % TSCREEN.size;
 	}
 
 	return 0;
@@ -1000,17 +981,14 @@ void
 tsetdirtattr(int attr)
 {
 	int i, j;
-	int y = TLINEOFFSET(0);
 
 	for (i = 0; i < term.row-1; i++) {
-		Line line = TSCREEN.buffer[y];
 		for (j = 0; j < term.col-1; j++) {
-			if (line[j].mode & attr) {
+			if (term.line[i][j].mode & attr) {
 				tsetdirt(i, i);
 				break;
 			}
 		}
-		y = (y+1) % TSCREEN.size;
 	}
 }
 
@@ -1023,19 +1001,27 @@ tfulldirt(void)
 void
 tcursor(int mode)
 {
+	static TCursor c[2];
+	int alt = IS_SET(MODE_ALTSCREEN);
+
 	if (mode == CURSOR_SAVE) {
-		TSCREEN.sc = term.c;
+		c[alt] = term.c;
 	} else if (mode == CURSOR_LOAD) {
-		term.c = TSCREEN.sc;
-		tmoveto(term.c.x, term.c.y);
+		term.c = c[alt];
+		tmoveto(c[alt].x, c[alt].y);
 	}
 }
 
 void
 treset(void)
 {
-	int i, j;
-	Glyph g = (Glyph){ .fg = defaultfg, .bg = defaultbg};
+	uint i;
+
+	term.c = (TCursor){{
+		.mode = ATTR_NULL,
+		.fg = defaultfg,
+		.bg = defaultbg
+	}, .x = 0, .y = 0, .state = CURSOR_DEFAULT};
 
 	memset(term.tabs, 0, term.col * sizeof(*term.tabs));
 	for (i = tabspaces; i < term.col; i += tabspaces)
@@ -1047,37 +1033,17 @@ treset(void)
 	term.charset = 0;
 
 	for (i = 0; i < 2; i++) {
-		term.screen[i].sc = (TCursor){{
-			.fg = defaultfg,
-			.bg = defaultbg
-		}};
-		term.screen[i].cur = 0;
-		term.screen[i].off = 0;
-		for (j = 0; j < term.row; ++j) {
-			if (term.col != term.linelen)
-				term.screen[i].buffer[j] = xrealloc(term.screen[i].buffer[j], term.col * sizeof(Glyph));
-			clearline(term.screen[i].buffer[j], g, 0, term.col);
-		}
-		for (j = term.row; j < term.screen[i].size; ++j) {
-			free(term.screen[i].buffer[j]);
-			term.screen[i].buffer[j] = NULL;
-		}
+		tmoveto(0, 0);
+		tcursor(CURSOR_SAVE);
+		tclearregion(0, 0, term.col-1, term.row-1);
+		tswapscreen();
 	}
-	tcursor(CURSOR_LOAD);
-	term.linelen = term.col;
-	tfulldirt();
 }
 
 void
 tnew(int col, int row)
 {
-	int i;
-	term = (Term){};
-	term.screen[0].buffer = xmalloc(HISTSIZE * sizeof(Line));
-	term.screen[0].size = HISTSIZE;
-	term.screen[1].buffer = NULL;
-	for (i = 0; i < HISTSIZE; ++i) term.screen[0].buffer[i] = NULL;
-
+	term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
 	tresize(col, row);
 	treset();
 }
@@ -1085,39 +1051,11 @@ tnew(int col, int row)
 void
 tswapscreen(void)
 {
-	term.mode ^= MODE_ALTSCREEN;
-	tfulldirt();
-}
+	Line *tmp = term.line;
 
-void
-kscrollup(const Arg *a)
-{
-	int n = a->i;
-
-	if (IS_SET(MODE_ALTSCREEN))
-		return;
-
-	if (n < 0) n = (-n) * term.row;
-	if (n > TSCREEN.size - term.row - TSCREEN.off) n = TSCREEN.size - term.row - TSCREEN.off;
-	while (!TLINE(-n)) --n;
-	TSCREEN.off += n;
-	selscroll(0, n);
-	tfulldirt();
-}
-
-void
-kscrolldown(const Arg *a)
-{
-
-	int n = a->i;
-
-	if (IS_SET(MODE_ALTSCREEN))
-		return;
-
-	if (n < 0) n = (-n) * term.row;
-	if (n > TSCREEN.off) n = TSCREEN.off;
-	TSCREEN.off -= n;
-	selscroll(0, -n);
+	term.line = term.alt;
+	term.alt = tmp;
+	term.mode ^= MODE_ALTSCREEN;
 	tfulldirt();
 }
 
@@ -1129,29 +1067,15 @@ tscrolldown(int orig, int n)
 
 	LIMIT(n, 0, term.bot-orig+1);
 
-	/* Ensure that lines are allocated */
-	for (i = -n; i < 0; i++) {
-		TLINE(i) = ensureline(TLINE(i));
-	}
+	tsetdirt(orig, term.bot-n);
+	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
-	/* Shift non-scrolling areas in ring buffer */
-	for (i = term.bot+1; i < term.row; i++) {
-		temp = TLINE(i);
-		TLINE(i) = TLINE(i-n);
-		TLINE(i-n) = temp;
-	}
-	for (i = 0; i < orig; i++) {
-		temp = TLINE(i);
-		TLINE(i) = TLINE(i-n);
-		TLINE(i-n) = temp;
+	for (i = term.bot; i >= orig+n; i--) {
+		temp = term.line[i];
+		term.line[i] = term.line[i-n];
+		term.line[i-n] = temp;
 	}
 
-	/* Scroll buffer */
-	TSCREEN.cur = (TSCREEN.cur + TSCREEN.size - n) % TSCREEN.size;
-	/* Clear lines that have entered the view */
-	tclearregion(0, orig, term.linelen-1, orig+n-1);
-	/* Redraw portion of the screen that has scrolled */
-	tsetdirt(orig+n-1, term.bot);
 	selscroll(orig, n);
 }
 
@@ -1163,29 +1087,15 @@ tscrollup(int orig, int n)
 
 	LIMIT(n, 0, term.bot-orig+1);
 
-	/* Ensure that lines are allocated */
-	for (i = term.row; i < term.row + n; i++) {
-		TLINE(i) = ensureline(TLINE(i));
-	}
+	tclearregion(0, orig, term.col-1, orig+n-1);
+	tsetdirt(orig+n, term.bot);
 
-	/* Shift non-scrolling areas in ring buffer */
-	for (i = orig-1; i >= 0; i--) {
-		temp = TLINE(i);
-		TLINE(i) = TLINE(i+n);
-		TLINE(i+n) = temp;
-	}
-	for (i = term.row-1; i >term.bot; i--) {
-		temp = TLINE(i);
-		TLINE(i) = TLINE(i+n);
-		TLINE(i+n) = temp;
+	for (i = orig; i <= term.bot-n; i++) {
+		temp = term.line[i];
+		term.line[i] = term.line[i+n];
+		term.line[i+n] = temp;
 	}
 
-	/* Scroll buffer */
-	TSCREEN.cur = (TSCREEN.cur + n) % TSCREEN.size;
-	/* Clear lines that have entered the view */
-	tclearregion(0, term.bot-n+1, term.linelen-1, term.bot);
-	/* Redraw portion of the screen that has scrolled */
-	tsetdirt(orig, term.bot-n+1);
 	selscroll(orig, -n);
 }
 
@@ -1289,7 +1199,6 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 		"⎻", "─", "⎼", "⎽", "├", "┤", "┴", "┬", /* p - w */
 		"│", "≤", "≥", "π", "≠", "£", "·", /* x - ~ */
 	};
-	Line line = TLINE(y);
 
 	/*
 	 * The table is proudly stolen from rxvt.
@@ -1298,28 +1207,28 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 	   BETWEEN(u, 0x41, 0x7e) && vt100_0[u - 0x41])
 		utf8decode(vt100_0[u - 0x41], &u, UTF_SIZ);
 
-	if (line[x].mode & ATTR_WIDE) {
+	if (term.line[y][x].mode & ATTR_WIDE) {
 		if (x+1 < term.col) {
-                        line[x+1].u = ' ';
-                        line[x+1].mode &= ~ATTR_WDUMMY;
+			term.line[y][x+1].u = ' ';
+			term.line[y][x+1].mode &= ~ATTR_WDUMMY;
 		}
-	} else if (line[x].mode & ATTR_WDUMMY) {
-		line[x-1].u = ' ';
-		line[x-1].mode &= ~ATTR_WIDE;
+	} 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;
-	line[x] = *attr;
-	line[x].u = u;
+	term.line[y][x] = *attr;
+	term.line[y][x].u = u;
 
 	if (isboxdraw(u))
-		line[x].mode |= ATTR_BOXDRAW;
+		term.line[y][x].mode |= ATTR_BOXDRAW;
 }
 
 void
 tclearregion(int x1, int y1, int x2, int y2)
 {
-	int x, y, L, S, temp;
+	int x, y, temp;
 	Glyph *gp;
 
 	if (x1 > x2)
@@ -1327,16 +1236,15 @@ tclearregion(int x1, int y1, int x2, int y2)
 	if (y1 > y2)
 		temp = y1, y1 = y2, y2 = temp;
 
-	LIMIT(x1, 0, term.linelen-1);
-	LIMIT(x2, 0, term.linelen-1);
+	LIMIT(x1, 0, term.col-1);
+	LIMIT(x2, 0, term.col-1);
 	LIMIT(y1, 0, term.row-1);
 	LIMIT(y2, 0, term.row-1);
 
-	L = TLINEOFFSET(y1);
 	for (y = y1; y <= y2; y++) {
 		term.dirty[y] = 1;
 		for (x = x1; x <= x2; x++) {
-			gp = &TSCREEN.buffer[L][x];
+			gp = &term.line[y][x];
 			if (selected(x, y))
 				selclear();
 			gp->fg = term.c.attr.fg;
@@ -1344,7 +1252,6 @@ tclearregion(int x1, int y1, int x2, int y2)
 			gp->mode = 0;
 			gp->u = ' ';
 		}
-		L = (L + 1) % TSCREEN.size;
 	}
 }
 
@@ -1359,7 +1266,7 @@ tdeletechar(int n)
 	dst = term.c.x;
 	src = term.c.x + n;
 	size = term.col - src;
-	line = TLINE(term.c.y);
+	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);
@@ -1376,7 +1283,7 @@ tinsertblank(int n)
 	dst = term.c.x + n;
 	src = term.c.x;
 	size = term.col - dst;
-	line = TLINE(term.c.y);
+	line = term.line[term.c.y];
 
 	memmove(&line[dst], &line[src], size * sizeof(Glyph));
 	tclearregion(src, term.c.y, dst - 1, term.c.y);
@@ -2197,7 +2104,7 @@ tdumpline(int n)
 	char buf[UTF_SIZ];
 	const Glyph *bp, *end;
 
-	bp = &TLINE(n)[0];
+	bp = &term.line[n][0];
 	end = &bp[MIN(tlinelen(n), term.col) - 1];
 	if (bp != end || bp->u != ' ') {
 		for ( ; bp <= end; ++bp)
@@ -2581,11 +2488,11 @@ check_control_code:
 	if (selected(term.c.x, term.c.y))
 		selclear();
 
-	gp = &TLINE(term.c.y)[term.c.x];
+	gp = &term.line[term.c.y][term.c.x];
 	if (IS_SET(MODE_WRAP) && (term.c.state & CURSOR_WRAPNEXT)) {
 		gp->mode |= ATTR_WRAP;
 		tnewline(1);
-		gp = &TLINE(term.c.y)[term.c.x];
+		gp = &term.line[term.c.y][term.c.x];
 	}
 
 	if (IS_SET(MODE_INSERT) && term.c.x+width < term.col)
@@ -2593,7 +2500,7 @@ check_control_code:
 
 	if (term.c.x+width > term.col) {
 		tnewline(1);
-		gp = &TLINE(term.c.y)[term.c.x];
+		gp = &term.line[term.c.y][term.c.x];
 	}
 
 	tsetchar(u, &term.c.attr, term.c.x, term.c.y);
@@ -2624,11 +2531,6 @@ twrite(const char *buf, int buflen, int show_ctrl)
 	Rune u;
 	int n;
 
-	if (TSCREEN.off) {
-		TSCREEN.off = 0;
-		tfulldirt();
-	}
-
 	for (n = 0; n < buflen; n += charsize) {
 		if (IS_SET(MODE_UTF8)) {
 			/* process a complete utf8 char */
@@ -2655,85 +2557,56 @@ twrite(const char *buf, int buflen, int show_ctrl)
 }
 
 void
-clearline(Line line, Glyph g, int x, int xend)
-{
-	int i;
-	g.mode = 0;
-	g.u = ' ';
-	for (i = x; i < xend; ++i) {
-		line[i] = g;
-	}
-}
-
-Line
-ensureline(Line line)
-{
-	if (!line) {
-		line = xmalloc(term.linelen * sizeof(Glyph));
-	}
-	return line;
-}
-
-void
 tresize(int col, int row)
 {
-	int i, j;
+	int i;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
-	int linelen = MAX(col, term.linelen);
 	int *bp;
+	TCursor c;
 
-	if (col < 1 || row < 1 || row > HISTSIZE) {
+	if (col < 1 || row < 1) {
 		fprintf(stderr,
 		        "tresize: error resizing to %dx%d\n", col, row);
 		return;
 	}
 
-	/* Shift buffer to keep the cursor where we expect it */
-	if (row <= term.c.y) {
-		term.screen[0].cur = (term.screen[0].cur - row + term.c.y + 1) % term.screen[0].size;
-	}
-
-	/* Resize and clear line buffers as needed */
-	if (linelen > term.linelen) {
-		for (i = 0; i < term.screen[0].size; ++i) {
-			if (term.screen[0].buffer[i]) {
-				term.screen[0].buffer[i] = xrealloc(term.screen[0].buffer[i], linelen * sizeof(Glyph));
-				clearline(term.screen[0].buffer[i], term.c.attr, term.linelen, linelen);
-			}
-		}
-		for (i = 0; i < minrow; ++i) {
-			term.screen[1].buffer[i] = xrealloc(term.screen[1].buffer[i], linelen * sizeof(Glyph));
-			clearline(term.screen[1].buffer[i], term.c.attr, term.linelen, linelen);
-		}
-	}
-	/* Allocate all visible lines for regular line buffer */
-	for (j = term.screen[0].cur, i = 0; i < row; ++i, j = (j + 1) % term.screen[0].size)
-	{
-		if (!term.screen[0].buffer[j]) {
-			term.screen[0].buffer[j] = xmalloc(linelen * sizeof(Glyph));
-		}
-		if (i >= term.row) {
-			clearline(term.screen[0].buffer[j], term.c.attr, 0, linelen);
-		}
+	/*
+	 * 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(term.line[i]);
+		free(term.alt[i]);
 	}
-	/* Resize alt screen */
-	term.screen[1].cur = 0;
-	term.screen[1].size = row;
-	for (i = row; i < term.row; ++i) {
-		free(term.screen[1].buffer[i]);
+	/* 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));
 	}
-	term.screen[1].buffer = xrealloc(term.screen[1].buffer, row * sizeof(Line));
-	for (i = term.row; i < row; ++i) {
-		term.screen[1].buffer[i] = xmalloc(linelen * sizeof(Glyph));
-		clearline(term.screen[1].buffer[i], term.c.attr, 0, linelen);
+	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));
+	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));
 
-	/* fix tabstops */
+	/* 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));
+	}
+
+	/* 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 (col > term.col) {
 		bp = term.tabs + term.col;
 
@@ -2743,16 +2616,26 @@ tresize(int col, int row)
 		for (bp += tabspaces; bp < term.tabs + col; bp += tabspaces)
 			*bp = 1;
 	}
-
 	/* update terminal size */
 	term.col = col;
 	term.row = row;
-	term.linelen = linelen;
 	/* reset scrolling region */
 	tsetscroll(0, row-1);
 	/* make use of the LIMIT in tmoveto */
 	tmoveto(term.c.x, term.c.y);
-	tfulldirt();
+	/* 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 (0 < col && minrow < row) {
+			tclearregion(0, minrow, col - 1, row - 1);
+		}
+		tswapscreen();
+		tcursor(CURSOR_LOAD);
+	}
+	term.c = c;
 }
 
 void
@@ -2764,15 +2647,14 @@ resettitle(void)
 void
 drawregion(int x1, int y1, int x2, int y2)
 {
-	int y, L;
+	int y;
 
-	L = TLINEOFFSET(y1);
 	for (y = y1; y < y2; y++) {
-		if (term.dirty[y]) {
-			term.dirty[y] = 0;
-			xdrawline(TSCREEN.buffer[L], x1, y, x2);
-		}
-		L = (L + 1) % TSCREEN.size;
+		if (!term.dirty[y])
+			continue;
+
+		term.dirty[y] = 0;
+		xdrawline(term.line[y], x1, y, x2);
 	}
 }
 
@@ -2787,15 +2669,14 @@ draw(void)
 	/* adjust cursor position */
 	LIMIT(term.ocx, 0, term.col-1);
 	LIMIT(term.ocy, 0, term.row-1);
-	if (TLINE(term.ocy)[term.ocx].mode & ATTR_WDUMMY)
+	if (term.line[term.ocy][term.ocx].mode & ATTR_WDUMMY)
 		term.ocx--;
-	if (TLINE(term.c.y)[cx].mode & ATTR_WDUMMY)
+	if (term.line[term.c.y][cx].mode & ATTR_WDUMMY)
 		cx--;
 
 	drawregion(0, 0, term.col, term.row);
-	if (TSCREEN.off == 0)
-		xdrawcursor(cx, term.c.y, TLINE(term.c.y)[cx],
-				term.ocx, term.ocy, TLINE(term.ocy)[term.ocx]);
+	xdrawcursor(cx, term.c.y, term.line[term.c.y][cx],
+			term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
 	term.ocx = cx;
 	term.ocy = term.c.y;
 	xfinishdraw();
@@ -2861,9 +2742,6 @@ copyurl(const Arg *arg) {
 		 *match = NULL;
 	URLdfa dfa = { 0 };
 
-	int y = TLINEOFFSET(0);
-	Line line = TSCREEN.buffer[y];
-
 	row = (sel.ob.x >= 0 && sel.nb.y > 0) ? sel.nb.y : term.bot;
 	LIMIT(row, term.top, term.bot);
 
@@ -2879,7 +2757,7 @@ copyurl(const Arg *arg) {
 		** we hit previous occurrence of URL
 		*/
 		for (col = colend; col--;)
-			if (daddch(&dfa, line[col].u < 128 ? line[col].u : ' '))
+			if (daddch(&dfa, term.line[row][col].u < 128 ? term.line[row][col].u : ' '))
 				break;
 
 		if (col >= 0)
diff --git a/st.h b/st.h
index 94293f9..f085e62 100644
--- a/st.h
+++ b/st.h
@@ -19,7 +19,6 @@
 
 #define TRUECOLOR(r,g,b)	(1 << 24 | (r) << 16 | (g) << 8 | (b))
 #define IS_TRUECOL(x)		(1 << 24 & (x))
-#define HISTSIZE            2000
 
 enum glyph_attribute {
 	ATTR_NULL       = 0,
diff --git a/x.c b/x.c
index ff736f7..6f2ddff 100644
--- a/x.c
+++ b/x.c
@@ -60,8 +60,6 @@ static void zoom(const Arg *);
 static void zoomabs(const Arg *);
 static void zoomreset(const Arg *);
 static void ttysend(const Arg *);
-void kscrollup(const Arg *);
-void kscrolldown(const Arg *);
 
 /* config.h for applying patches and the configuration. */
 #include "config.h"