Added mouse scroll

config.def.h

@@ -6,12 +6,14 @@
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
 
-static char *font = "Ubuntu Mono:pixelsize=12:antialias=true:autohint=true";
+#define FONTSIZE "14"
+
+static char *font = "Ubuntu Mono:pixelsize="FONTSIZE":antialias=true:autohint=true";
 static char *font2[] = {
-    "Ubuntu Mono:pixelsize=12:antialias=true:autohint=true",
+    "Ubuntu Mono:pixelsize="FONTSIZE":antialias=true:autohint=true",
-    "Font Awesome 6 Free Solid:pixelsize=12:antialias=true:autohint=true"
+    "Font Awesome 6 Free Solid:pixelsize="FONTSIZE":antialias=true:autohint=true"
 };
-static int borderpx = 2;
+static int borderpx = 10;
 
 /*
  * What program is execed by st depends of these precedence rules:
@@ -181,6 +183,8 @@ static uint forcemousemod = ShiftMask;
  */
 static MouseShortcut mshortcuts[] = {
 	/* mask                 button   function        argument       release */
+	{ XK_ANY_MOD,           Button4, kscrollup,      {.i = 1} },
+	{ XK_ANY_MOD,           Button5, kscrolldown,    {.i = 1} },
 	{ XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
 	{ ShiftMask,            Button4, ttysend,        {.s = "\033[5;2~"} },
 	{ XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
@@ -206,6 +210,8 @@ 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} },
 };
 
 /*

config.h

@@ -6,12 +6,14 @@
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
 
-static char *font = "Ubuntu Mono:pixelsize=12:antialias=true:autohint=true";
+#define FONTSIZE "14"
+
+static char *font = "Ubuntu Mono:pixelsize="FONTSIZE":antialias=true:autohint=true";
 static char *font2[] = {
-    "Ubuntu Mono:pixelsize=12:antialias=true:autohint=true",
+    "Ubuntu Mono:pixelsize="FONTSIZE":antialias=true:autohint=true",
-    "Font Awesome 6 Free Solid:pixelsize=12:antialias=true:autohint=true"
+    "Font Awesome 6 Free Solid:pixelsize="FONTSIZE":antialias=true:autohint=true"
 };
-static int borderpx = 2;
+static int borderpx = 10;
 
 /*
  * What program is execed by st depends of these precedence rules:
@@ -181,6 +183,8 @@ static uint forcemousemod = ShiftMask;
  */
 static MouseShortcut mshortcuts[] = {
 	/* mask                 button   function        argument       release */
+	{ XK_ANY_MOD,           Button4, kscrollup,      {.i = 1} },
+	{ XK_ANY_MOD,           Button5, kscrolldown,    {.i = 1} },
 	{ XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
 	{ ShiftMask,            Button4, ttysend,        {.s = "\033[5;2~"} },
 	{ XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
@@ -206,6 +210,8 @@ 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} },
 };
 
 /*

st.c

@@ -42,6 +42,12 @@
 #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.argp[(n)-1] + 1)
+#define STRESCARGJUST(n)	(*(strescseq.argp[n]) = '\0', STRESCARGREST(n))
+
+#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,
@@ -109,12 +115,20 @@ typedef struct {
 	int alt;
 } Selection;
 
+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 */
+	LineBuffer screen[2]; /* screen and alternate screen */
-	Line *alt;    /* alternate screen */
+	int linelen;  /* allocated line length */
 	int *dirty;   /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int ocx;      /* old cursor col */
@@ -148,7 +162,7 @@ typedef struct {
 	char *buf;             /* allocated raw string */
 	size_t siz;            /* allocation size */
 	size_t len;            /* raw string length */
-	char *args[STR_ARG_SIZ];
+	char *argp[STR_ARG_SIZ];
 	int narg;              /* nb of args */
 } STREscape;
 
@@ -203,6 +217,8 @@ 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);
@@ -408,11 +424,12 @@ 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;
@@ -521,7 +538,7 @@ 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;
@@ -536,14 +553,14 @@ 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)))
@@ -564,14 +581,14 @@ 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;
 				}
@@ -602,13 +619,13 @@ 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;
 
@@ -949,12 +966,15 @@ 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;
@@ -976,14 +996,17 @@ 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;
 	}
 }
 
@@ -1000,23 +1023,18 @@ tcursor(int mode)
 	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];
+		term.c = TSCREEN.sc;
-		tmoveto(c[alt].x, c[alt].y);
+		tmoveto(term.c.x, term.c.y);
 	}
 }
 
 void
 treset(void)
 {
-	uint i;
+	int i, j;
-
+	Glyph g = (Glyph){ .fg = defaultfg, .bg = defaultbg};
-	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)
@@ -1028,17 +1046,37 @@ treset(void)
 	term.charset = 0;
 
 	for (i = 0; i < 2; i++) {
-		tmoveto(0, 0);
+		term.screen[i].sc = (TCursor){{
-		tcursor(CURSOR_SAVE);
+			.fg = defaultfg,
-		tclearregion(0, 0, term.col-1, term.row-1);
+			.bg = defaultbg
-		tswapscreen();
+		}};
+		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();
 }
@@ -1046,14 +1084,42 @@ 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)
 {
@@ -1062,15 +1128,28 @@ tscrolldown(int orig, int n)
 
 	LIMIT(n, 0, term.bot-orig+1);
 
-	tsetdirt(orig, term.bot-n);
+	for (i = -n; i < 0; i++) {
-	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
+		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;
 	}
 
+	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);
 }
 
@@ -1082,15 +1161,30 @@ tscrollup(int orig, int n)
 
 	LIMIT(n, 0, term.bot-orig+1);
 
-	tclearregion(0, orig, term.col-1, orig+n-1);
+	/* Ensure that lines are allocated */
-	tsetdirt(orig+n, term.bot);
+	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);
 }
 
@@ -1194,6 +1288,7 @@ 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.
@@ -1202,25 +1297,25 @@ 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 = ' ';
+			line[x+1].u = ' ';
-			term.line[y][x+1].mode &= ~ATTR_WDUMMY;
+			line[x+1].mode &= ~ATTR_WDUMMY;
 		}
-	} else if (term.line[y][x].mode & ATTR_WDUMMY) {
+	} else if (line[x].mode & ATTR_WDUMMY) {
-		term.line[y][x-1].u = ' ';
+		line[x-1].u = ' ';
-		term.line[y][x-1].mode &= ~ATTR_WIDE;
+		line[x-1].mode &= ~ATTR_WIDE;
  	}
 
 	term.dirty[y] = 1;
-	term.line[y][x] = *attr;
+	line[x] = *attr;
-	term.line[y][x].u = u;
+	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)
@@ -1228,15 +1323,16 @@ 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(x1, 0, term.linelen-1);
-	LIMIT(x2, 0, term.col-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;
@@ -1244,6 +1340,7 @@ tclearregion(int x1, int y1, int x2, int y2)
 			gp->mode = 0;
 			gp->u = ' ';
 		}
+		L = (L + 1) % TSCREEN.size;
 	}
 }
 
@@ -1258,7 +1355,7 @@ 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);
@@ -1275,7 +1372,7 @@ 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);
@@ -1872,29 +1969,30 @@ strhandle(void)
 	};
 
 	term.esc &= ~(ESC_STR_END|ESC_STR);
-	strparse();
+	strescseq.buf[strescseq.len] = '\0';
-	par = (narg = strescseq.narg) ? atoi(strescseq.args[0]) : 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]);
+				xsettitle(STRESCARGREST(1));
-				xseticontitle(strescseq.args[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(2));
 				if (dec) {
 					xsetsel(dec);
 					xclipcopy();
@@ -1908,7 +2006,7 @@ strhandle(void)
 		case 12:
 			if (narg < 2)
 				break;
-			p = strescseq.args[1];
+			p = STRESCARGREST(1);
 			if ((j = par - 10) < 0 || j >= LEN(osc_table))
 				break; /* shouldn't be possible */
 
@@ -1924,10 +2022,10 @@ strhandle(void)
 		case 4: /* color set */
 			if (narg < 3)
 				break;
-			p = strescseq.args[2];
+			p = STRESCARGJUST(2);
 			/* FALLTHROUGH */
 		case 104: /* color reset */
-			j = (narg > 1) ? atoi(strescseq.args[1]) : -1;
+			j = (narg > 1) ? atoi(STRESCARGJUST(1)) : -1;
 
 			if (p && !strcmp(p, "?")) {
 				osc_color_response(j, 0, 1);
@@ -1947,7 +2045,7 @@ strhandle(void)
 		}
 		break;
 	case 'k': /* old title set compatibility */
-		xsettitle(strescseq.args[0]);
+		xsettitle(strescseq.buf);
 		return;
 	case 'P': /* DCS -- Device Control String */
 	case '_': /* APC -- Application Program Command */
@@ -1966,18 +2064,17 @@ 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.argp[strescseq.narg++] = p;
 		if (c == '\0')
 			return;
-		*p++ = '\0';
+		p++;
 	}
 }
 
@@ -2069,7 +2166,7 @@ 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)
@@ -2452,11 +2549,11 @@ 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)
@@ -2464,7 +2561,7 @@ 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);
@@ -2495,6 +2592,11 @@ 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 */
@@ -2521,15 +2623,35 @@ 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;
@@ -2540,37 +2662,52 @@ tresize(int col, int row)
 	 * 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++) {
+	/* Shift buffer to keep the cursor where we expect it */
-		free(term.line[i]);
+	if (row <= term.c.y) {
-		free(term.alt[i]);
+		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) {
+	/* Allocate all visible lines for regular line buffer */
-		memmove(term.line, term.line + i, row * sizeof(Line));
+	for (j = term.screen[0].cur, i = 0; i < row; ++i, j = (j + 1) % term.screen[0].size)
-		memmove(term.alt, term.alt + i, row * sizeof(Line));
+	{
+		if (!term.screen[0].buffer[j]) {
+			term.screen[0].buffer[j] = xmalloc(linelen * sizeof(Glyph));
 		}
-	for (i += row; i < term.row; i++) {
+		if (i >= term.row) {
-		free(term.line[i]);
+			clearline(term.screen[0].buffer[j], term.c.attr, 0, linelen);
-		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 */
+	/* fix tabstops */
-	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;
 
@@ -2580,26 +2717,16 @@ 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) */
+	tfulldirt();
-	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
@@ -2611,14 +2738,15 @@ 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])
+		if (term.dirty[y]) {
-			continue;
-
 			term.dirty[y] = 0;
-		xdrawline(term.line[y], x1, y, x2);
+			xdrawline(TSCREEN.buffer[L], x1, y, x2);
+		}
+		L = (L + 1) % TSCREEN.size;
 	}
 }
 
@@ -2633,14 +2761,15 @@ 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],
+	if (TSCREEN.off == 0)
-			term.ocx, term.ocy, term.line[term.ocy][term.ocx]);
+		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();

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            10000
 
 enum glyph_attribute {
 	ATTR_NULL       = 0,

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"