change font and color scheme keys

(apply st-scrollback-ringbuffer-0.9.2.diff)

from the patch header:

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.

config.def.h

@@ -5,7 +5,7 @@
  *
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
-static char *font = "Liberation Mono:pixelsize=12:antialias=true:autohint=true";
+static char *font = "FiraCode Nerd Font:size=10";
 static int borderpx = 2;
 
 /*
@@ -93,46 +93,87 @@ char *termname = "st-256color";
  */
 unsigned int tabspaces = 8;
 
-/* Terminal colors (16 first used in escape sequence) */
-static const char *colorname[] = {
-	/* 8 normal colors */
-	"black",
-	"red3",
-	"green3",
-	"yellow3",
-	"blue2",
-	"magenta3",
-	"cyan3",
-	"gray90",
+typedef struct {
+	const char* const colors[258]; /* terminal colors */
+	unsigned int fg;               /* foreground */
+	unsigned int bg;               /* background */
+	unsigned int cs;               /* cursor */
+	unsigned int rcs;              /* reverse cursor */
+} ColorScheme;
+/*
+ * Terminal colors (16 first used in escape sequence,
+ * 2 last for custom cursor color),
+ * foreground, background, cursor, reverse cursor
+ */
+static const ColorScheme schemes[] = {
+	// st (dark)
+	{{"black", "red3", "green3", "yellow3",
+	  "blue2", "magenta3", "cyan3", "gray90",
+	  "gray50", "red", "green", "yellow",
+	  "#5c5cff", "magenta", "cyan", "white",
+	  [256]="#cccccc", "#555555"}, 7, 0, 256, 257},
 
-	/* 8 bright colors */
-	"gray50",
-	"red",
-	"green",
-	"yellow",
-	"#5c5cff",
-	"magenta",
-	"cyan",
-	"white",
+	// Alacritty (dark)
+	{{"#1d1f21", "#cc6666", "#b5bd68", "#f0c674",
+	  "#81a2be", "#b294bb", "#8abeb7", "#c5c8c6",
+	  "#666666", "#d54e53", "#b9ca4a", "#e7c547",
+	  "#7aa6da", "#c397d8", "#70c0b1", "#eaeaea",
+	  [256]="#cccccc", "#555555"}, 7, 0, 256, 257},
 
-	[255] = 0,
+	// One Half dark
+	{{"#282c34", "#e06c75", "#98c379", "#e5c07b",
+	  "#61afef", "#c678dd", "#56b6c2", "#dcdfe4",
+	  "#282c34", "#e06c75", "#98c379", "#e5c07b",
+	  "#61afef", "#c678dd", "#56b6c2", "#dcdfe4",
+	  [256]="#cccccc", "#555555"}, 7, 0, 256, 257},
 
-	/* more colors can be added after 255 to use with DefaultXX */
-	"#cccccc",
-	"#555555",
-	"gray90", /* default foreground colour */
-	"black", /* default background colour */
+	// One Half light
+	{{"#fafafa", "#e45649", "#50a14f", "#c18401",
+      "#0184bc", "#a626a4", "#0997b3", "#383a42",
+	  "#fafafa", "#e45649", "#50a14f", "#c18401",
+	  "#0184bc", "#a626a4", "#0997b3", "#383a42",
+	  [256]="#cccccc", "#555555"}, 7, 0, 256, 257},
+
+	// Solarized dark
+	{{"#073642", "#dc322f", "#859900", "#b58900",
+	  "#268bd2", "#d33682", "#2aa198", "#eee8d5",
+	  "#002b36", "#cb4b16", "#586e75", "#657b83",
+	  "#839496", "#6c71c4", "#93a1a1", "#fdf6e3",
+	  [256]="#93a1a1", "#fdf6e3"}, 12, 8, 256, 257},
+
+	// Solarized light
+	{{"#eee8d5", "#dc322f", "#859900", "#b58900",
+	  "#268bd2", "#d33682", "#2aa198", "#073642",
+	  "#fdf6e3", "#cb4b16", "#93a1a1", "#839496",
+	  "#657b83", "#6c71c4", "#586e75", "#002b36",
+	  [256]="#586e75", "#002b36"}, 12, 8, 256, 257},
+
+	// Gruvbox dark
+	{{"#282828", "#cc241d", "#98971a", "#d79921",
+	  "#458588", "#b16286", "#689d6a", "#a89984",
+	  "#928374", "#fb4934", "#b8bb26", "#fabd2f",
+	  "#83a598", "#d3869b", "#8ec07c", "#ebdbb2",
+	  [256]="#ebdbb2", "#555555"}, 15, 0, 256, 257},
+
+	// Gruvbox light
+	{{"#fbf1c7", "#cc241d", "#98971a", "#d79921",
+	  "#458588", "#b16286", "#689d6a", "#7c6f64",
+	  "#928374", "#9d0006", "#79740e", "#b57614",
+	  "#076678", "#8f3f71", "#427b58", "#3c3836",
+	  [256]="#3c3836", "#555555"}, 15, 0, 256, 257},
 };
 
+static const char * const * colorname;
+int colorscheme = 0;
 
 /*
  * Default colors (colorname index)
  * foreground, background, cursor, reverse cursor
  */
-unsigned int defaultfg = 258;
-unsigned int defaultbg = 259;
-unsigned int defaultcs = 256;
-static unsigned int defaultrcs = 257;
+unsigned int defaultfg;
+unsigned int defaultbg;
+unsigned int defaultcs;
+static unsigned int defaultrcs;
 
 /*
  * Default shape of cursor
@@ -201,6 +242,18 @@ static Shortcut shortcuts[] = {
 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+	{ MODKEY|ControlMask,   XK_1,           selectscheme,   {.i =  0} },
+	{ MODKEY|ControlMask,   XK_2,           selectscheme,   {.i =  1} },
+	{ MODKEY|ControlMask,   XK_3,           selectscheme,   {.i =  2} },
+	{ MODKEY|ControlMask,   XK_4,           selectscheme,   {.i =  3} },
+	{ MODKEY|ControlMask,   XK_5,           selectscheme,   {.i =  4} },
+	{ MODKEY|ControlMask,   XK_6,           selectscheme,   {.i =  5} },
+	{ MODKEY|ControlMask,   XK_7,           selectscheme,   {.i =  6} },
+	{ MODKEY|ControlMask,   XK_8,           selectscheme,   {.i =  7} },
+	{ MODKEY|ControlMask,   XK_9,           nextscheme,     {.i = -1} },
+	{ MODKEY|ControlMask,   XK_0,           nextscheme,     {.i = +1} },
+	{ ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
+	{ ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
 };
 
 /*

config.mk

@@ -1,5 +1,5 @@
 # st version
-VERSION = 0.9.2
+VERSION = 0.9.3
 
 # Customize below to fit your system
 

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 */
@@ -203,6 +216,8 @@ 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 +423,12 @@ 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 +537,7 @@ 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 +552,14 @@ 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 +580,14 @@ 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 +618,13 @@ 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 +965,15 @@ 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 +995,17 @@ 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;
 	}
 }
 
@@ -996,27 +1018,19 @@ 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)
@@ -1028,17 +1042,37 @@ 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();
 }
@@ -1046,14 +1080,42 @@ 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 +1124,29 @@ 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);
-
-	for (i = term.bot; i >= orig+n; i--) {
-		temp = term.line[i];
-		term.line[i] = term.line[i-n];
-		term.line[i-n] = temp;
+	/* Ensure that lines are allocated */
+	for (i = -n; i < 0; i++) {
+		TLINE(i) = ensureline(TLINE(i));
 	}
 
+	/* 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);
 }
 
@@ -1082,15 +1158,29 @@ 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);
-
-	for (i = orig; i <= term.bot-n; i++) {
-		temp = term.line[i];
-		term.line[i] = term.line[i+n];
-		term.line[i+n] = temp;
+	/* Ensure that lines are allocated */
+	for (i = term.row; i < term.row + n; i++) {
+		TLINE(i) = ensureline(TLINE(i));
 	}
 
+	/* 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);
 }
 
@@ -1197,6 +1287,7 @@ 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.
@@ -1205,25 +1296,25 @@ 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)
@@ -1231,15 +1322,16 @@ 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;
@@ -1247,6 +1339,7 @@ tclearregion(int x1, int y1, int x2, int y2)
 			gp->mode = 0;
 			gp->u = ' ';
 		}
+		L = (L + 1) % TSCREEN.size;
 	}
 }
 
@@ -1261,7 +1354,7 @@ 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);
@@ -1278,7 +1371,7 @@ 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);
@@ -1420,16 +1513,22 @@ tsetattr(const int *attr, int l)
 			if ((idx = tdefcolor(attr, &i, l)) >= 0)
 				term.c.attr.fg = idx;
 			break;
-		case 39:
+		case 39: /* set foreground color to default */
 			term.c.attr.fg = defaultfg;
 			break;
 		case 48:
 			if ((idx = tdefcolor(attr, &i, l)) >= 0)
 				term.c.attr.bg = idx;
 			break;
-		case 49:
+		case 49: /* set background color to default */
 			term.c.attr.bg = defaultbg;
 			break;
+		case 58:
+			/* This starts a sequence to change the color of
+			 * "underline" pixels. We don't support that and
+			 * instead eat up a following "5;n" or "2;r;g;b". */
+			tdefcolor(attr, &i, l);
+			break;
 		default:
 			if (BETWEEN(attr[i], 30, 37)) {
 				term.c.attr.fg = attr[i] - 30;
@@ -1526,7 +1625,7 @@ tsetmode(int priv, int set, const int *args, int narg)
 			case 1006: /* 1006: extended reporting mode */
 				xsetmode(set, MODE_MOUSESGR);
 				break;
-			case 1034:
+			case 1034: /* 1034: enable 8-bit mode for keyboard input */
 				xsetmode(set, MODE_8BIT);
 				break;
 			case 1049: /* swap screen & set/restore cursor as xterm */
@@ -1534,8 +1633,8 @@ tsetmode(int priv, int set, const int *args, int narg)
 					break;
 				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
 				/* FALLTHROUGH */
-			case 47: /* swap screen */
-			case 1047:
+			case 47: /* swap screen buffer */
+			case 1047: /* swap screen buffer */
 				if (!allowaltscreen)
 					break;
 				alt = IS_SET(MODE_ALTSCREEN);
@@ -1548,7 +1647,7 @@ tsetmode(int priv, int set, const int *args, int narg)
 				if (*args != 1049)
 					break;
 				/* FALLTHROUGH */
-			case 1048:
+			case 1048: /* save/restore cursor (like DECSC/DECRC) */
 				tcursor((set) ? CURSOR_SAVE : CURSOR_LOAD);
 				break;
 			case 2004: /* 2004: bracketed paste mode */
@@ -1705,7 +1804,7 @@ csihandle(void)
 			}
 			break;
 		case 1: /* above */
-			if (term.c.y > 1)
+			if (term.c.y > 0)
 				tclearregion(0, 0, term.col-1, term.c.y-1);
 			tclearregion(0, term.c.y, term.c.x, term.c.y);
 			break;
@@ -1801,7 +1900,11 @@ csihandle(void)
 		tcursor(CURSOR_SAVE);
 		break;
 	case 'u': /* DECRC -- Restore cursor position (ANSI.SYS) */
+		if (csiescseq.priv) {
+			goto unknown;
+		} else {
 			tcursor(CURSOR_LOAD);
+		}
 		break;
 	case ' ':
 		switch (csiescseq.mode[1]) {
@@ -1903,7 +2006,7 @@ strhandle(void)
 			if (narg > 1)
 				xsettitle(strescseq.args[1]);
 			return;
-		case 52:
+		case 52: /* manipulate selection data */
 			if (narg > 2 && allowwindowops) {
 				dec = base64dec(strescseq.args[2]);
 				if (dec) {
@@ -1914,9 +2017,9 @@ strhandle(void)
 				}
 			}
 			return;
-		case 10:
-		case 11:
-		case 12:
+		case 10: /* set dynamic VT100 text foreground color */
+		case 11: /* set dynamic VT100 text background color */
+		case 12: /* set dynamic text cursor color */
 			if (narg < 2)
 				break;
 			p = strescseq.args[1];
@@ -1957,6 +2060,19 @@ strhandle(void)
 				tfulldirt();
 			}
 			return;
+		case 110: /* reset dynamic VT100 text foreground color */
+		case 111: /* reset dynamic VT100 text background color */
+		case 112: /* reset dynamic text cursor color */
+			if (narg != 1)
+				break;
+			if ((j = par - 110) < 0 || j >= LEN(osc_table))
+				break; /* shouldn't be possible */
+			if (xsetcolorname(osc_table[j].idx, NULL)) {
+				fprintf(stderr, "erresc: %s color not found\n", osc_table[j].str);
+			} else {
+				tfulldirt();
+			}
+			return;
 		}
 		break;
 	case 'k': /* old title set compatibility */
@@ -2082,7 +2198,7 @@ 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)
@@ -2175,6 +2291,28 @@ tstrsequence(uchar c)
 	term.esc |= ESC_STR;
 }
 
+void
+tupdatebgcolor(int oldbg, int newbg)
+{
+	for (int y = 0; y < term.row; y++) {
+		for (int x = 0; x < term.col; x++) {
+			if (TLINE(y)[x].bg == oldbg)
+				TLINE(y)[x].bg = newbg;
+		}
+	}
+}
+
+void
+tupdatefgcolor(int oldfg, int newfg)
+{
+	for (int y = 0; y < term.row; y++) {
+		for (int x = 0; x < term.col; x++) {
+			if (TLINE(y)[x].fg == oldfg)
+				TLINE(y)[x].fg = newfg;
+		}
+	}
+}
+
 void
 tcontrolcode(uchar ascii)
 {
@@ -2469,11 +2607,11 @@ 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) {
@@ -2486,7 +2624,7 @@ check_control_code:
 			tnewline(1);
 		else
 			tmoveto(term.col - width, term.c.y);
-		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);
@@ -2517,6 +2655,11 @@ 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 */
@@ -2543,56 +2686,85 @@ 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;
 	}
-	/* 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));
+
+	/* 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 += row; i < term.row; i++) {
-		free(term.line[i]);
-		free(term.alt[i]);
+		}
+		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);
+		}
+	}
+	/* 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;
 
@@ -2602,26 +2774,16 @@ 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
@@ -2633,14 +2795,15 @@ 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;
-
+		if (term.dirty[y]) {
 			term.dirty[y] = 0;
-		xdrawline(term.line[y], x1, y, x2);
+			xdrawline(TSCREEN.buffer[L], x1, y, x2);
+		}
+		L = (L + 1) % TSCREEN.size;
 	}
 }
 
@@ -2655,14 +2818,15 @@ 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();

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,
@@ -90,6 +91,8 @@ int tattrset(int);
 void tnew(int, int);
 void tresize(int, int);
 void tsetdirtattr(int);
+void tupdatebgcolor(int, int);
+void tupdatefgcolor(int, int);
 void ttyhangup(void);
 int ttynew(const char *, char *, const char *, char **);
 size_t ttyread(void);

x.c

@@ -59,6 +59,10 @@ static void zoom(const Arg *);
 static void zoomabs(const Arg *);
 static void zoomreset(const Arg *);
 static void ttysend(const Arg *);
+static void nextscheme(const Arg *);
+static void selectscheme(const Arg *);
+void kscrollup(const Arg *);
+void kscrolldown(const Arg *);
 
 /* config.h for applying patches and the configuration. */
 #include "config.h"
@@ -185,6 +189,7 @@ static void mousesel(XEvent *, int);
 static void mousereport(XEvent *);
 static char *kmap(KeySym, uint);
 static int match(uint, uint);
+static void updatescheme(void);
 
 static void run(void);
 static void usage(void);
@@ -801,7 +806,7 @@ xloadcols(void)
 		for (cp = dc.col; cp < &dc.col[dc.collen]; ++cp)
 			XftColorFree(xw.dpy, xw.vis, xw.cmap, cp);
 	} else {
-		dc.collen = MAX(LEN(colorname), 256);
+		dc.collen = 258;
 		dc.col = xmalloc(dc.collen * sizeof(Color));
 	}
 
@@ -2036,6 +2041,47 @@ usage(void)
 	    " [stty_args ...]\n", argv0, argv0);
 }
 
+void
+nextscheme(const Arg *arg)
+{
+	colorscheme += arg->i;
+	if (colorscheme >= (int)LEN(schemes))
+		colorscheme = 0;
+	else if (colorscheme < 0)
+		colorscheme = LEN(schemes) - 1;
+	updatescheme();
+}
+
+void
+selectscheme(const Arg *arg)
+{
+	if (BETWEEN(arg->i, 0, LEN(schemes)-1)) {
+		colorscheme = arg->i;
+		updatescheme();
+	}
+}
+
+void
+updatescheme(void)
+{
+	int oldbg, oldfg;
+
+	oldbg = defaultbg;
+	oldfg = defaultfg;
+	colorname = schemes[colorscheme].colors;
+	defaultbg = schemes[colorscheme].bg;
+	defaultfg = schemes[colorscheme].fg;
+	defaultcs = schemes[colorscheme].cs;
+	defaultrcs = schemes[colorscheme].rcs;
+	xloadcols();
+	if (defaultbg != oldbg)
+		tupdatebgcolor(oldbg, defaultbg);
+	if (defaultfg != oldfg)
+		tupdatefgcolor(oldfg, defaultfg);
+	cresize(win.w, win.h);
+	redraw();
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -2088,6 +2134,12 @@ main(int argc, char *argv[])
 	} ARGEND;
 
 run:
+	colorname = schemes[colorscheme].colors;
+	defaultbg = schemes[colorscheme].bg;
+	defaultfg = schemes[colorscheme].fg;
+	defaultcs = schemes[colorscheme].cs;
+	defaultrcs = schemes[colorscheme].rcs;
+
 	if (argc > 0) /* eat all remaining arguments */
 		opt_cmd = argv;