Add scrollback and alpha patches

7 files changed, 655 insertions, 57 deletions

diff --git a/config.def.h b/config.def.h
index 2cd740a..c194b34 100644
--- a/config.def.h
+++ b/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 Mono:pixelsize=18:antialias=true:autohint=true";
 static int borderpx = 2;
 
 /*
@@ -93,27 +93,30 @@ char *termname = "st-256color";
  */
 unsigned int tabspaces = 8;
 
+/* bg opacity */
+float alpha = 0.8;
+
 /* Terminal colors (16 first used in escape sequence) */
 static const char *colorname[] = {
 	/* 8 normal colors */
-	"black",
-	"red3",
-	"green3",
-	"yellow3",
-	"blue2",
-	"magenta3",
-	"cyan3",
-	"gray90",
+	"#1b1c1d",
+	"#89231d",
+	"#198844",
+	"#ae7518",
+	"#2b55b2",
+	"#784e93",
+	"#2783a1",
+	"#b4b7b5",
 
 	/* 8 bright colors */
-	"gray50",
-	"red",
-	"green",
-	"yellow",
-	"#5c5cff",
-	"magenta",
-	"cyan",
-	"white",
+	"#969896",
+	"#cc342b",
+	"#4eec4e",
+	"#fba922",
+	"#3971ed",
+	"#a36ac7",
+	"#39c1ed",
+	"#ffffff",
 
 	[255] = 0,
 
@@ -193,14 +196,18 @@ static Shortcut shortcuts[] = {
 	{ ControlMask,          XK_Print,       toggleprinter,  {.i =  0} },
 	{ ShiftMask,            XK_Print,       printscreen,    {.i =  0} },
 	{ XK_ANY_MOD,           XK_Print,       printsel,       {.i =  0} },
-	{ TERMMOD,              XK_Prior,       zoom,           {.f = +1} },
-	{ TERMMOD,              XK_Next,        zoom,           {.f = -1} },
+	{ TERMMOD,              XK_plus,        zoom,           {.f = +1} },
+	{ TERMMOD,              XK_underscore,  zoom,           {.f = -1} },
 	{ TERMMOD,              XK_Home,        zoomreset,      {.f =  0} },
 	{ TERMMOD,              XK_C,           clipcopy,       {.i =  0} },
 	{ TERMMOD,              XK_V,           clippaste,      {.i =  0} },
 	{ TERMMOD,              XK_Y,           selpaste,       {.i =  0} },
 	{ ShiftMask,            XK_Insert,      selpaste,       {.i =  0} },
 	{ TERMMOD,              XK_Num_Lock,    numlock,        {.i =  0} },
+  { TERMMOD,              XK_Up,          kscrollup,      {.i = +1} },
+  { TERMMOD,              XK_Down,        kscrolldown,    {.i = +1} },
+  { TERMMOD,              XK_Page_Up,     kscrollup,      {.i = -1} },
+  { TERMMOD,              XK_Page_Down,   kscrolldown,    {.i = -1} },
 };
 
 /*
diff --git a/config.mk b/config.mk
index fdc29a7..069a6c2 100644
--- a/config.mk
+++ b/config.mk
@@ -16,7 +16,7 @@ PKG_CONFIG = pkg-config
 INCS = -I$(X11INC) \
        `$(PKG_CONFIG) --cflags fontconfig` \
        `$(PKG_CONFIG) --cflags freetype2`
-LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft \
+LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft -lXrender\
        `$(PKG_CONFIG) --libs fontconfig` \
        `$(PKG_CONFIG) --libs freetype2`
 
diff --git a/patches/st-alpha-20220206-0.8.5.diff b/patches/st-alpha-20220206-0.8.5.diff
new file mode 100644
index 0000000..ab029f6
--- /dev/null
+++ b/patches/st-alpha-20220206-0.8.5.diff
@@ -0,0 +1,146 @@
+diff --git a/config.def.h b/config.def.h
+index 91ab8ca..6af616e 100644
+--- a/config.def.h
++++ b/config.def.h
+@@ -93,6 +93,9 @@ char *termname = "st-256color";
+  */
+ unsigned int tabspaces = 8;
+ 
++/* bg opacity */
++float alpha = 0.8;
++
+ /* Terminal colors (16 first used in escape sequence) */
+ static const char *colorname[] = {
+ 	/* 8 normal colors */
+diff --git a/config.mk b/config.mk
+index 4c4c5d5..0114bad 100644
+--- a/config.mk
++++ b/config.mk
+@@ -16,7 +16,7 @@ PKG_CONFIG = pkg-config
+ INCS = -I$(X11INC) \
+        `$(PKG_CONFIG) --cflags fontconfig` \
+        `$(PKG_CONFIG) --cflags freetype2`
+-LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft \
++LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft -lXrender\
+        `$(PKG_CONFIG) --libs fontconfig` \
+        `$(PKG_CONFIG) --libs freetype2`
+ 
+diff --git a/st.h b/st.h
+index 519b9bd..8bb533d 100644
+--- a/st.h
++++ b/st.h
+@@ -126,3 +126,4 @@ extern unsigned int tabspaces;
+ extern unsigned int defaultfg;
+ extern unsigned int defaultbg;
+ extern unsigned int defaultcs;
++extern float alpha;
+diff --git a/x.c b/x.c
+index 8a16faa..ddf4178 100644
+--- a/x.c
++++ b/x.c
+@@ -105,6 +105,7 @@ typedef struct {
+ 	XSetWindowAttributes attrs;
+ 	int scr;
+ 	int isfixed; /* is fixed geometry? */
++	int depth; /* bit depth */
+ 	int l, t; /* left and top offset */
+ 	int gm; /* geometry mask */
+ } XWindow;
+@@ -243,6 +244,7 @@ static char *usedfont = NULL;
+ static double usedfontsize = 0;
+ static double defaultfontsize = 0;
+ 
++static char *opt_alpha = NULL;
+ static char *opt_class = NULL;
+ static char **opt_cmd  = NULL;
+ static char *opt_embed = NULL;
+@@ -736,7 +738,7 @@ xresize(int col, int row)
+ 
+ 	XFreePixmap(xw.dpy, xw.buf);
+ 	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h,
+-			DefaultDepth(xw.dpy, xw.scr));
++			xw.depth);
+ 	XftDrawChange(xw.draw, xw.buf);
+ 	xclear(0, 0, win.w, win.h);
+ 
+@@ -796,6 +798,13 @@ xloadcols(void)
+ 			else
+ 				die("could not allocate color %d\n", i);
+ 		}
++
++	/* set alpha value of bg color */
++	if (opt_alpha)
++		alpha = strtof(opt_alpha, NULL);
++	dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
++	dc.col[defaultbg].pixel &= 0x00FFFFFF;
++	dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
+ 	loaded = 1;
+ }
+ 
+@@ -1118,11 +1127,23 @@ xinit(int cols, int rows)
+ 	Window parent;
+ 	pid_t thispid = getpid();
+ 	XColor xmousefg, xmousebg;
++	XWindowAttributes attr;
++	XVisualInfo vis;
+ 
+ 	if (!(xw.dpy = XOpenDisplay(NULL)))
+ 		die("can't open display\n");
+ 	xw.scr = XDefaultScreen(xw.dpy);
+-	xw.vis = XDefaultVisual(xw.dpy, xw.scr);
++
++	if (!(opt_embed && (parent = strtol(opt_embed, NULL, 0)))) {
++		parent = XRootWindow(xw.dpy, xw.scr);
++		xw.depth = 32;
++	} else {
++		XGetWindowAttributes(xw.dpy, parent, &attr);
++		xw.depth = attr.depth;
++	}
++
++	XMatchVisualInfo(xw.dpy, xw.scr, xw.depth, TrueColor, &vis);
++	xw.vis = vis.visual;
+ 
+ 	/* font */
+ 	if (!FcInit())
+@@ -1132,7 +1153,7 @@ xinit(int cols, int rows)
+ 	xloadfonts(usedfont, 0);
+ 
+ 	/* colors */
+-	xw.cmap = XDefaultColormap(xw.dpy, xw.scr);
++	xw.cmap = XCreateColormap(xw.dpy, parent, xw.vis, None);
+ 	xloadcols();
+ 
+ 	/* adjust fixed window geometry */
+@@ -1152,19 +1173,15 @@ xinit(int cols, int rows)
+ 		| ButtonMotionMask | ButtonPressMask | ButtonReleaseMask;
+ 	xw.attrs.colormap = xw.cmap;
+ 
+-	if (!(opt_embed && (parent = strtol(opt_embed, NULL, 0))))
+-		parent = XRootWindow(xw.dpy, xw.scr);
+ 	xw.win = XCreateWindow(xw.dpy, parent, xw.l, xw.t,
+-			win.w, win.h, 0, XDefaultDepth(xw.dpy, xw.scr), InputOutput,
++			win.w, win.h, 0, xw.depth, InputOutput,
+ 			xw.vis, CWBackPixel | CWBorderPixel | CWBitGravity
+ 			| CWEventMask | CWColormap, &xw.attrs);
+ 
+ 	memset(&gcvalues, 0, sizeof(gcvalues));
+ 	gcvalues.graphics_exposures = False;
+-	dc.gc = XCreateGC(xw.dpy, parent, GCGraphicsExposures,
+-			&gcvalues);
+-	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h,
+-			DefaultDepth(xw.dpy, xw.scr));
++	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h, xw.depth);
++	dc.gc = XCreateGC(xw.dpy, xw.buf, GCGraphicsExposures, &gcvalues);
+ 	XSetForeground(xw.dpy, dc.gc, dc.col[defaultbg].pixel);
+ 	XFillRectangle(xw.dpy, xw.buf, dc.gc, 0, 0, win.w, win.h);
+ 
+@@ -2019,6 +2036,9 @@ main(int argc, char *argv[])
+ 	case 'a':
+ 		allowaltscreen = 0;
+ 		break;
++	case 'A':
++		opt_alpha = EARGF(usage());
++		break;
+ 	case 'c':
+ 		opt_class = EARGF(usage());
+ 		break;
diff --git a/patches/st-scrollback-0.9.2.diff b/patches/st-scrollback-0.9.2.diff
new file mode 100644
index 0000000..f9782e8
--- /dev/null
+++ b/patches/st-scrollback-0.9.2.diff
@@ -0,0 +1,351 @@
+diff --git a/config.def.h b/config.def.h
+index 2cd740a..40b7d93 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 b9f66e7..2478942 100644
+--- a/st.c
++++ b/st.c
+@@ -35,6 +35,7 @@
+ #define ESC_ARG_SIZ   16
+ #define STR_BUF_SIZ   ESC_BUF_SIZ
+ #define STR_ARG_SIZ   ESC_ARG_SIZ
++#define HISTSIZE      2000
+ 
+ /* macros */
+ #define IS_SET(flag)		((term.mode & (flag)) != 0)
+@@ -42,6 +43,9 @@
+ #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
+ #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
+ #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
++#define TLINE(y)		((y) < term.scr ? term.hist[((y) + term.histi - \
++            term.scr + HISTSIZE + 1) % HISTSIZE] : \
++            term.line[(y) - term.scr])
+ 
+ enum term_mode {
+ 	MODE_WRAP        = 1 << 0,
+@@ -115,6 +119,9 @@ typedef struct {
+ 	int col;      /* nb col */
+ 	Line *line;   /* screen */
+ 	Line *alt;    /* alternate screen */
++	Line hist[HISTSIZE]; /* history buffer */
++	int histi;    /* history index */
++	int scr;      /* scroll back */
+ 	int *dirty;   /* dirtyness of lines */
+ 	TCursor c;    /* cursor */
+ 	int ocx;      /* old cursor col */
+@@ -185,8 +192,8 @@ static void tnewline(int);
+ static void tputtab(int);
+ static void tputc(Rune);
+ static void treset(void);
+-static void tscrollup(int, int);
+-static void tscrolldown(int, int);
++static void tscrollup(int, int, int);
++static void tscrolldown(int, int, int);
+ static void tsetattr(const int *, int);
+ static void tsetchar(Rune, const Glyph *, int, int);
+ static void tsetdirt(int, int);
+@@ -409,10 +416,10 @@ tlinelen(int y)
+ {
+ 	int i = term.col;
+ 
+-	if (term.line[y][i - 1].mode & ATTR_WRAP)
++	if (TLINE(y)[i - 1].mode & ATTR_WRAP)
+ 		return i;
+ 
+-	while (i > 0 && term.line[y][i - 1].u == ' ')
++	while (i > 0 && TLINE(y)[i - 1].u == ' ')
+ 		--i;
+ 
+ 	return i;
+@@ -521,7 +528,7 @@ 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 +543,14 @@ 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 +571,14 @@ 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 +609,13 @@ 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;
+ 
+@@ -844,6 +851,9 @@ void
+ ttywrite(const char *s, size_t n, int may_echo)
+ {
+ 	const char *next;
++	Arg arg = (Arg) { .i = term.scr };
++
++	kscrolldown(&arg);
+ 
+ 	if (may_echo && IS_SET(MODE_ECHO))
+ 		twrite(s, n, 1);
+@@ -1055,13 +1065,53 @@ tswapscreen(void)
+ }
+ 
+ void
+-tscrolldown(int orig, int n)
++kscrolldown(const Arg* a)
++{
++	int n = a->i;
++
++	if (n < 0)
++		n = term.row + n;
++
++	if (n > term.scr)
++		n = term.scr;
++
++	if (term.scr > 0) {
++		term.scr -= n;
++		selscroll(0, -n);
++		tfulldirt();
++	}
++}
++
++void
++kscrollup(const Arg* a)
++{
++	int n = a->i;
++
++	if (n < 0)
++		n = term.row + n;
++
++	if (term.scr <= HISTSIZE-n) {
++		term.scr += n;
++		selscroll(0, n);
++		tfulldirt();
++	}
++}
++
++void
++tscrolldown(int orig, int n, int copyhist)
+ {
+ 	int i;
+ 	Line temp;
+ 
+ 	LIMIT(n, 0, term.bot-orig+1);
+ 
++	if (copyhist) {
++		term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
++		temp = term.hist[term.histi];
++		term.hist[term.histi] = term.line[term.bot];
++		term.line[term.bot] = temp;
++	}
++
+ 	tsetdirt(orig, term.bot-n);
+ 	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
+ 
+@@ -1071,17 +1121,28 @@ tscrolldown(int orig, int n)
+ 		term.line[i-n] = temp;
+ 	}
+ 
+-	selscroll(orig, n);
++	if (term.scr == 0)
++		selscroll(orig, n);
+ }
+ 
+ void
+-tscrollup(int orig, int n)
++tscrollup(int orig, int n, int copyhist)
+ {
+ 	int i;
+ 	Line temp;
+ 
+ 	LIMIT(n, 0, term.bot-orig+1);
+ 
++	if (copyhist) {
++		term.histi = (term.histi + 1) % HISTSIZE;
++		temp = term.hist[term.histi];
++		term.hist[term.histi] = term.line[orig];
++		term.line[orig] = temp;
++	}
++
++	if (term.scr > 0 && term.scr < HISTSIZE)
++		term.scr = MIN(term.scr + n, HISTSIZE-1);
++
+ 	tclearregion(0, orig, term.col-1, orig+n-1);
+ 	tsetdirt(orig+n, term.bot);
+ 
+@@ -1091,7 +1152,8 @@ tscrollup(int orig, int n)
+ 		term.line[i+n] = temp;
+ 	}
+ 
+-	selscroll(orig, -n);
++	if (term.scr == 0)
++		selscroll(orig, -n);
+ }
+ 
+ void
+@@ -1120,7 +1182,7 @@ tnewline(int first_col)
+ 	int y = term.c.y;
+ 
+ 	if (y == term.bot) {
+-		tscrollup(term.top, 1);
++		tscrollup(term.top, 1, 1);
+ 	} else {
+ 		y++;
+ 	}
+@@ -1285,14 +1347,14 @@ void
+ tinsertblankline(int n)
+ {
+ 	if (BETWEEN(term.c.y, term.top, term.bot))
+-		tscrolldown(term.c.y, n);
++		tscrolldown(term.c.y, n, 0);
+ }
+ 
+ void
+ tdeleteline(int n)
+ {
+ 	if (BETWEEN(term.c.y, term.top, term.bot))
+-		tscrollup(term.c.y, n);
++		tscrollup(term.c.y, n, 0);
+ }
+ 
+ int32_t
+@@ -1730,11 +1792,11 @@ csihandle(void)
+ 	case 'S': /* SU -- Scroll <n> line up */
+ 		if (csiescseq.priv) break;
+ 		DEFAULT(csiescseq.arg[0], 1);
+-		tscrollup(term.top, csiescseq.arg[0]);
++		tscrollup(term.top, csiescseq.arg[0], 0);
+ 		break;
+ 	case 'T': /* SD -- Scroll <n> line down */
+ 		DEFAULT(csiescseq.arg[0], 1);
+-		tscrolldown(term.top, csiescseq.arg[0]);
++		tscrolldown(term.top, csiescseq.arg[0], 0);
+ 		break;
+ 	case 'L': /* IL -- Insert <n> blank lines */
+ 		DEFAULT(csiescseq.arg[0], 1);
+@@ -2306,7 +2368,7 @@ eschandle(uchar ascii)
+ 		return 0;
+ 	case 'D': /* IND -- Linefeed */
+ 		if (term.c.y == term.bot) {
+-			tscrollup(term.top, 1);
++			tscrollup(term.top, 1, 1);
+ 		} else {
+ 			tmoveto(term.c.x, term.c.y+1);
+ 		}
+@@ -2319,7 +2381,7 @@ eschandle(uchar ascii)
+ 		break;
+ 	case 'M': /* RI -- Reverse index */
+ 		if (term.c.y == term.top) {
+-			tscrolldown(term.top, 1);
++			tscrolldown(term.top, 1, 1);
+ 		} else {
+ 			tmoveto(term.c.x, term.c.y-1);
+ 		}
+@@ -2542,7 +2604,7 @@ twrite(const char *buf, int buflen, int show_ctrl)
+ void
+ tresize(int col, int row)
+ {
+-	int i;
++	int i, j;
+ 	int minrow = MIN(row, term.row);
+ 	int mincol = MIN(col, term.col);
+ 	int *bp;
+@@ -2579,6 +2641,14 @@ tresize(int col, int row)
+ 	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
+ 	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
+ 
++	for (i = 0; i < HISTSIZE; i++) {
++		term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
++		for (j = mincol; j < col; j++) {
++			term.hist[i][j] = term.c.attr;
++			term.hist[i][j].u = ' ';
++		}
++	}
++
+ 	/* 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));
+@@ -2637,7 +2707,7 @@ drawregion(int x1, int y1, int x2, int y2)
+ 			continue;
+ 
+ 		term.dirty[y] = 0;
+-		xdrawline(term.line[y], x1, y, x2);
++		xdrawline(TLINE(y), x1, y, x2);
+ 	}
+ }
+ 
+@@ -2658,8 +2728,9 @@ draw(void)
+ 		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 (term.scr == 0)
++		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();
+diff --git a/st.h b/st.h
+index fd3b0d8..818a6f8 100644
+--- a/st.h
++++ b/st.h
+@@ -81,6 +81,8 @@ void die(const char *, ...);
+ void redraw(void);
+ void draw(void);
+ 
++void kscrolldown(const Arg *);
++void kscrollup(const Arg *);
+ void printscreen(const Arg *);
+ void printsel(const Arg *);
+ void sendbreak(const Arg *);
diff --git a/st.c b/st.c
index b9f66e7..2478942 100644
--- a/st.c
+++ b/st.c
@@ -35,6 +35,7 @@
 #define ESC_ARG_SIZ   16
 #define STR_BUF_SIZ   ESC_BUF_SIZ
 #define STR_ARG_SIZ   ESC_ARG_SIZ
+#define HISTSIZE      2000
 
 /* macros */
 #define IS_SET(flag)		((term.mode & (flag)) != 0)
@@ -42,6 +43,9 @@
 #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
 #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
+#define TLINE(y)		((y) < term.scr ? term.hist[((y) + term.histi - \
+            term.scr + HISTSIZE + 1) % HISTSIZE] : \
+            term.line[(y) - term.scr])
 
 enum term_mode {
 	MODE_WRAP        = 1 << 0,
@@ -115,6 +119,9 @@ typedef struct {
 	int col;      /* nb col */
 	Line *line;   /* screen */
 	Line *alt;    /* alternate screen */
+	Line hist[HISTSIZE]; /* history buffer */
+	int histi;    /* history index */
+	int scr;      /* scroll back */
 	int *dirty;   /* dirtyness of lines */
 	TCursor c;    /* cursor */
 	int ocx;      /* old cursor col */
@@ -185,8 +192,8 @@ static void tnewline(int);
 static void tputtab(int);
 static void tputc(Rune);
 static void treset(void);
-static void tscrollup(int, int);
-static void tscrolldown(int, int);
+static void tscrollup(int, int, int);
+static void tscrolldown(int, int, int);
 static void tsetattr(const int *, int);
 static void tsetchar(Rune, const Glyph *, int, int);
 static void tsetdirt(int, int);
@@ -409,10 +416,10 @@ tlinelen(int y)
 {
 	int i = term.col;
 
-	if (term.line[y][i - 1].mode & ATTR_WRAP)
+	if (TLINE(y)[i - 1].mode & ATTR_WRAP)
 		return i;
 
-	while (i > 0 && term.line[y][i - 1].u == ' ')
+	while (i > 0 && TLINE(y)[i - 1].u == ' ')
 		--i;
 
 	return i;
@@ -521,7 +528,7 @@ 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 +543,14 @@ 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 +571,14 @@ 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 +609,13 @@ 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;
 
@@ -844,6 +851,9 @@ void
 ttywrite(const char *s, size_t n, int may_echo)
 {
 	const char *next;
+	Arg arg = (Arg) { .i = term.scr };
+
+	kscrolldown(&arg);
 
 	if (may_echo && IS_SET(MODE_ECHO))
 		twrite(s, n, 1);
@@ -1055,13 +1065,53 @@ tswapscreen(void)
 }
 
 void
-tscrolldown(int orig, int n)
+kscrolldown(const Arg* a)
+{
+	int n = a->i;
+
+	if (n < 0)
+		n = term.row + n;
+
+	if (n > term.scr)
+		n = term.scr;
+
+	if (term.scr > 0) {
+		term.scr -= n;
+		selscroll(0, -n);
+		tfulldirt();
+	}
+}
+
+void
+kscrollup(const Arg* a)
+{
+	int n = a->i;
+
+	if (n < 0)
+		n = term.row + n;
+
+	if (term.scr <= HISTSIZE-n) {
+		term.scr += n;
+		selscroll(0, n);
+		tfulldirt();
+	}
+}
+
+void
+tscrolldown(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi - 1 + HISTSIZE) % HISTSIZE;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[term.bot];
+		term.line[term.bot] = temp;
+	}
+
 	tsetdirt(orig, term.bot-n);
 	tclearregion(0, term.bot-n+1, term.col-1, term.bot);
 
@@ -1071,17 +1121,28 @@ tscrolldown(int orig, int n)
 		term.line[i-n] = temp;
 	}
 
-	selscroll(orig, n);
+	if (term.scr == 0)
+		selscroll(orig, n);
 }
 
 void
-tscrollup(int orig, int n)
+tscrollup(int orig, int n, int copyhist)
 {
 	int i;
 	Line temp;
 
 	LIMIT(n, 0, term.bot-orig+1);
 
+	if (copyhist) {
+		term.histi = (term.histi + 1) % HISTSIZE;
+		temp = term.hist[term.histi];
+		term.hist[term.histi] = term.line[orig];
+		term.line[orig] = temp;
+	}
+
+	if (term.scr > 0 && term.scr < HISTSIZE)
+		term.scr = MIN(term.scr + n, HISTSIZE-1);
+
 	tclearregion(0, orig, term.col-1, orig+n-1);
 	tsetdirt(orig+n, term.bot);
 
@@ -1091,7 +1152,8 @@ tscrollup(int orig, int n)
 		term.line[i+n] = temp;
 	}
 
-	selscroll(orig, -n);
+	if (term.scr == 0)
+		selscroll(orig, -n);
 }
 
 void
@@ -1120,7 +1182,7 @@ tnewline(int first_col)
 	int y = term.c.y;
 
 	if (y == term.bot) {
-		tscrollup(term.top, 1);
+		tscrollup(term.top, 1, 1);
 	} else {
 		y++;
 	}
@@ -1285,14 +1347,14 @@ void
 tinsertblankline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrolldown(term.c.y, n);
+		tscrolldown(term.c.y, n, 0);
 }
 
 void
 tdeleteline(int n)
 {
 	if (BETWEEN(term.c.y, term.top, term.bot))
-		tscrollup(term.c.y, n);
+		tscrollup(term.c.y, n, 0);
 }
 
 int32_t
@@ -1730,11 +1792,11 @@ csihandle(void)
 	case 'S': /* SU -- Scroll <n> line up */
 		if (csiescseq.priv) break;
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrollup(term.top, csiescseq.arg[0]);
+		tscrollup(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'T': /* SD -- Scroll <n> line down */
 		DEFAULT(csiescseq.arg[0], 1);
-		tscrolldown(term.top, csiescseq.arg[0]);
+		tscrolldown(term.top, csiescseq.arg[0], 0);
 		break;
 	case 'L': /* IL -- Insert <n> blank lines */
 		DEFAULT(csiescseq.arg[0], 1);
@@ -2306,7 +2368,7 @@ eschandle(uchar ascii)
 		return 0;
 	case 'D': /* IND -- Linefeed */
 		if (term.c.y == term.bot) {
-			tscrollup(term.top, 1);
+			tscrollup(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y+1);
 		}
@@ -2319,7 +2381,7 @@ eschandle(uchar ascii)
 		break;
 	case 'M': /* RI -- Reverse index */
 		if (term.c.y == term.top) {
-			tscrolldown(term.top, 1);
+			tscrolldown(term.top, 1, 1);
 		} else {
 			tmoveto(term.c.x, term.c.y-1);
 		}
@@ -2542,7 +2604,7 @@ twrite(const char *buf, int buflen, int show_ctrl)
 void
 tresize(int col, int row)
 {
-	int i;
+	int i, j;
 	int minrow = MIN(row, term.row);
 	int mincol = MIN(col, term.col);
 	int *bp;
@@ -2579,6 +2641,14 @@ tresize(int col, int row)
 	term.dirty = xrealloc(term.dirty, row * sizeof(*term.dirty));
 	term.tabs = xrealloc(term.tabs, col * sizeof(*term.tabs));
 
+	for (i = 0; i < HISTSIZE; i++) {
+		term.hist[i] = xrealloc(term.hist[i], col * sizeof(Glyph));
+		for (j = mincol; j < col; j++) {
+			term.hist[i][j] = term.c.attr;
+			term.hist[i][j].u = ' ';
+		}
+	}
+
 	/* 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));
@@ -2637,7 +2707,7 @@ drawregion(int x1, int y1, int x2, int y2)
 			continue;
 
 		term.dirty[y] = 0;
-		xdrawline(term.line[y], x1, y, x2);
+		xdrawline(TLINE(y), x1, y, x2);
 	}
 }
 
@@ -2658,8 +2728,9 @@ draw(void)
 		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 (term.scr == 0)
+		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();
diff --git a/st.h b/st.h
index fd3b0d8..78762a2 100644
--- a/st.h
+++ b/st.h
@@ -81,6 +81,8 @@ void die(const char *, ...);
 void redraw(void);
 void draw(void);
 
+void kscrolldown(const Arg *);
+void kscrollup(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);
@@ -124,3 +126,4 @@ extern unsigned int tabspaces;
 extern unsigned int defaultfg;
 extern unsigned int defaultbg;
 extern unsigned int defaultcs;
+extern float alpha;
diff --git a/x.c b/x.c
index bd23686..1e12ac8 100644
--- a/x.c
+++ b/x.c
@@ -105,6 +105,7 @@ typedef struct {
 	XSetWindowAttributes attrs;
 	int scr;
 	int isfixed; /* is fixed geometry? */
+	int depth; /* bit depth */
 	int l, t; /* left and top offset */
 	int gm; /* geometry mask */
 } XWindow;
@@ -243,6 +244,7 @@ static char *usedfont = NULL;
 static double usedfontsize = 0;
 static double defaultfontsize = 0;
 
+static char *opt_alpha = NULL;
 static char *opt_class = NULL;
 static char **opt_cmd  = NULL;
 static char *opt_embed = NULL;
@@ -752,7 +754,7 @@ xresize(int col, int row)
 
 	XFreePixmap(xw.dpy, xw.buf);
 	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h,
-			DefaultDepth(xw.dpy, xw.scr));
+			xw.depth);
 	XftDrawChange(xw.draw, xw.buf);
 	xclear(0, 0, win.w, win.h);
 
@@ -812,6 +814,13 @@ xloadcols(void)
 			else
 				die("could not allocate color %d\n", i);
 		}
+
+	/* set alpha value of bg color */
+	if (opt_alpha)
+		alpha = strtof(opt_alpha, NULL);
+	dc.col[defaultbg].color.alpha = (unsigned short)(0xffff * alpha);
+	dc.col[defaultbg].pixel &= 0x00FFFFFF;
+	dc.col[defaultbg].pixel |= (unsigned char)(0xff * alpha) << 24;
 	loaded = 1;
 }
 
@@ -1134,11 +1143,23 @@ xinit(int cols, int rows)
 	Window parent;
 	pid_t thispid = getpid();
 	XColor xmousefg, xmousebg;
+	XWindowAttributes attr;
+	XVisualInfo vis;
 
 	if (!(xw.dpy = XOpenDisplay(NULL)))
 		die("can't open display\n");
 	xw.scr = XDefaultScreen(xw.dpy);
-	xw.vis = XDefaultVisual(xw.dpy, xw.scr);
+
+	if (!(opt_embed && (parent = strtol(opt_embed, NULL, 0)))) {
+		parent = XRootWindow(xw.dpy, xw.scr);
+		xw.depth = 32;
+	} else {
+		XGetWindowAttributes(xw.dpy, parent, &attr);
+		xw.depth = attr.depth;
+	}
+
+	XMatchVisualInfo(xw.dpy, xw.scr, xw.depth, TrueColor, &vis);
+	xw.vis = vis.visual;
 
 	/* font */
 	if (!FcInit())
@@ -1148,7 +1169,7 @@ xinit(int cols, int rows)
 	xloadfonts(usedfont, 0);
 
 	/* colors */
-	xw.cmap = XDefaultColormap(xw.dpy, xw.scr);
+	xw.cmap = XCreateColormap(xw.dpy, parent, xw.vis, None);
 	xloadcols();
 
 	/* adjust fixed window geometry */
@@ -1168,19 +1189,15 @@ xinit(int cols, int rows)
 		| ButtonMotionMask | ButtonPressMask | ButtonReleaseMask;
 	xw.attrs.colormap = xw.cmap;
 
-	if (!(opt_embed && (parent = strtol(opt_embed, NULL, 0))))
-		parent = XRootWindow(xw.dpy, xw.scr);
 	xw.win = XCreateWindow(xw.dpy, parent, xw.l, xw.t,
-			win.w, win.h, 0, XDefaultDepth(xw.dpy, xw.scr), InputOutput,
+			win.w, win.h, 0, xw.depth, InputOutput,
 			xw.vis, CWBackPixel | CWBorderPixel | CWBitGravity
 			| CWEventMask | CWColormap, &xw.attrs);
 
 	memset(&gcvalues, 0, sizeof(gcvalues));
 	gcvalues.graphics_exposures = False;
-	dc.gc = XCreateGC(xw.dpy, parent, GCGraphicsExposures,
-			&gcvalues);
-	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h,
-			DefaultDepth(xw.dpy, xw.scr));
+	xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h, xw.depth);
+	dc.gc = XCreateGC(xw.dpy, xw.buf, GCGraphicsExposures, &gcvalues);
 	XSetForeground(xw.dpy, dc.gc, dc.col[defaultbg].pixel);
 	XFillRectangle(xw.dpy, xw.buf, dc.gc, 0, 0, win.w, win.h);
 
@@ -2044,6 +2061,9 @@ main(int argc, char *argv[])
 	case 'a':
 		allowaltscreen = 0;
 		break;
+	case 'A':
+		opt_alpha = EARGF(usage());
+		break;
 	case 'c':
 		opt_class = EARGF(usage());
 		break;