diff --git a/Makefile b/Makefile
index 470ac86..5aa2a1f 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@

 include config.mk

-SRC = st.c x.c
+SRC = st.c x.c boxdraw.c
 OBJ = $(SRC:.c=.o)

 all: options st
@@ -23,6 +23,7 @@ config.h:

 st.o: config.h st.h win.h
 x.o: arg.h config.h st.h win.h
+boxdraw.o: config.h st.h boxdraw_data.h

 $(OBJ): config.h config.mk

@@ -47,7 +48,7 @@ install: st
 	mkdir -p $(DESTDIR)$(MANPREFIX)/man1
 	sed "s/VERSION/$(VERSION)/g" < st.1 > $(DESTDIR)$(MANPREFIX)/man1/st.1
 	chmod 644 $(DESTDIR)$(MANPREFIX)/man1/st.1
-	tic -sx st.info
+	tic -xs st.info
 	@echo Please see the README file regarding the terminfo entry of st.

 uninstall:
diff --git a/boxdraw.c b/boxdraw.c
new file mode 100644
index 0000000..28a92d0
--- /dev/null
+++ b/boxdraw.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright 2018 Avi Halachmi (:avih) avihpit@yahoo.com https://github.com/avih
+ * MIT/X Consortium License
+ */
+
+#include <X11/Xft/Xft.h>
+#include "st.h"
+#include "boxdraw_data.h"
+
+/* Rounded non-negative integers division of n / d  */
+#define DIV(n, d) (((n) + (d) / 2) / (d))
+
+static Display *xdpy;
+static Colormap xcmap;
+static XftDraw *xd;
+static Visual *xvis;
+
+static void drawbox(int, int, int, int, XftColor *, XftColor *, ushort);
+static void drawboxlines(int, int, int, int, XftColor *, ushort);
+
+/* public API */
+
+void
+boxdraw_xinit(Display *dpy, Colormap cmap, XftDraw *draw, Visual *vis)
+{
+	xdpy = dpy; xcmap = cmap; xd = draw, xvis = vis;
+}
+
+int
+isboxdraw(Rune u)
+{
+	Rune block = u & ~0xff;
+	return (boxdraw && block == 0x2500 && boxdata[(uint8_t)u]) ||
+	       (boxdraw_braille && block == 0x2800);
+}
+
+/* the "index" is actually the entire shape data encoded as ushort */
+ushort
+boxdrawindex(const Glyph *g)
+{
+	if (boxdraw_braille && (g->u & ~0xff) == 0x2800)
+		return BRL | (uint8_t)g->u;
+	if (boxdraw_bold && (g->mode & ATTR_BOLD))
+		return BDB | boxdata[(uint8_t)g->u];
+	return boxdata[(uint8_t)g->u];
+}
+
+void
+drawboxes(int x, int y, int cw, int ch, XftColor *fg, XftColor *bg,
+          const XftGlyphFontSpec *specs, int len)
+{
+	for ( ; len-- > 0; x += cw, specs++)
+		drawbox(x, y, cw, ch, fg, bg, (ushort)specs->glyph);
+}
+
+/* implementation */
+
+void
+drawbox(int x, int y, int w, int h, XftColor *fg, XftColor *bg, ushort bd)
+{
+	ushort cat = bd & ~(BDB | 0xff);  /* mask out bold and data */
+	if (bd & (BDL | BDA)) {
+		/* lines (light/double/heavy/arcs) */
+		drawboxlines(x, y, w, h, fg, bd);
+
+	} else if (cat == BBD) {
+		/* lower (8-X)/8 block */
+		int d = DIV((uint8_t)bd * h, 8);
+		XftDrawRect(xd, fg, x, y + d, w, h - d);
+
+	} else if (cat == BBU) {
+		/* upper X/8 block */
+		XftDrawRect(xd, fg, x, y, w, DIV((uint8_t)bd * h, 8));
+
+	} else if (cat == BBL) {
+		/* left X/8 block */
+		XftDrawRect(xd, fg, x, y, DIV((uint8_t)bd * w, 8), h);
+
+	} else if (cat == BBR) {
+		/* right (8-X)/8 block */
+		int d = DIV((uint8_t)bd * w, 8);
+		XftDrawRect(xd, fg, x + d, y, w - d, h);
+
+	} else if (cat == BBQ) {
+		/* Quadrants */
+		int w2 = DIV(w, 2), h2 = DIV(h, 2);
+		if (bd & TL)
+			XftDrawRect(xd, fg, x, y, w2, h2);
+		if (bd & TR)
+			XftDrawRect(xd, fg, x + w2, y, w - w2, h2);
+		if (bd & BL)
+			XftDrawRect(xd, fg, x, y + h2, w2, h - h2);
+		if (bd & BR)
+			XftDrawRect(xd, fg, x + w2, y + h2, w - w2, h - h2);
+
+	} else if (bd & BBS) {
+		/* Shades - data is 1/2/3 for 25%/50%/75% alpha, respectively */
+		int d = (uint8_t)bd;
+		XftColor xfc;
+		XRenderColor xrc = { .alpha = 0xffff };
+
+		xrc.red = DIV(fg->color.red * d + bg->color.red * (4 - d), 4);
+		xrc.green = DIV(fg->color.green * d + bg->color.green * (4 - d), 4);
+		xrc.blue = DIV(fg->color.blue * d + bg->color.blue * (4 - d), 4);
+
+		XftColorAllocValue(xdpy, xvis, xcmap, &xrc, &xfc);
+		XftDrawRect(xd, &xfc, x, y, w, h);
+		XftColorFree(xdpy, xvis, xcmap, &xfc);
+
+	} else if (cat == BRL) {
+		/* braille, each data bit corresponds to one dot at 2x4 grid */
+		int w1 = DIV(w, 2);
+		int h1 = DIV(h, 4), h2 = DIV(h, 2), h3 = DIV(3 * h, 4);
+
+		if (bd & 1)   XftDrawRect(xd, fg, x, y, w1, h1);
+		if (bd & 2)   XftDrawRect(xd, fg, x, y + h1, w1, h2 - h1);
+		if (bd & 4)   XftDrawRect(xd, fg, x, y + h2, w1, h3 - h2);
+		if (bd & 8)   XftDrawRect(xd, fg, x + w1, y, w - w1, h1);
+		if (bd & 16)  XftDrawRect(xd, fg, x + w1, y + h1, w - w1, h2 - h1);
+		if (bd & 32)  XftDrawRect(xd, fg, x + w1, y + h2, w - w1, h3 - h2);
+		if (bd & 64)  XftDrawRect(xd, fg, x, y + h3, w1, h - h3);
+		if (bd & 128) XftDrawRect(xd, fg, x + w1, y + h3, w - w1, h - h3);
+
+	}
+}
+
+void
+drawboxlines(int x, int y, int w, int h, XftColor *fg, ushort bd)
+{
+	/* s: stem thickness. width/8 roughly matches underscore thickness. */
+	/* We draw bold as 1.5 * normal-stem and at least 1px thicker.      */
+	/* doubles draw at least 3px, even when w or h < 3. bold needs 6px. */
+	int mwh = MIN(w, h);
+	int base_s = MAX(1, DIV(mwh, 8));
+	int bold = (bd & BDB) && mwh >= 6;  /* possibly ignore boldness */
+	int s = bold ? MAX(base_s + 1, DIV(3 * base_s, 2)) : base_s;
+	int w2 = DIV(w - s, 2), h2 = DIV(h - s, 2);
+	/* the s-by-s square (x + w2, y + h2, s, s) is the center texel.    */
+	/* The base length (per direction till edge) includes this square.  */
+
+	int light = bd & (LL | LU | LR | LD);
+	int double_ = bd & (DL | DU | DR | DD);
+
+	if (light) {
+		/* d: additional (negative) length to not-draw the center   */
+		/* texel - at arcs and avoid drawing inside (some) doubles  */
+		int arc = bd & BDA;
+		int multi_light = light & (light - 1);
+		int multi_double = double_ & (double_ - 1);
+		/* light crosses double only at DH+LV, DV+LH (ref. shapes)  */
+		int d = arc || (multi_double && !multi_light) ? -s : 0;
+
+		if (bd & LL)
+			XftDrawRect(xd, fg, x, y + h2, w2 + s + d, s);
+		if (bd & LU)
+			XftDrawRect(xd, fg, x + w2, y, s, h2 + s + d);
+		if (bd & LR)
+			XftDrawRect(xd, fg, x + w2 - d, y + h2, w - w2 + d, s);
+		if (bd & LD)
+			XftDrawRect(xd, fg, x + w2, y + h2 - d, s, h - h2 + d);
+	}
+
+	/* double lines - also align with light to form heavy when combined */
+	if (double_) {
+		/*
+		* going clockwise, for each double-ray: p is additional length
+		* to the single-ray nearer to the previous direction, and n to
+		* the next. p and n adjust from the base length to lengths
+		* which consider other doubles - shorter to avoid intersections
+		* (p, n), or longer to draw the far-corner texel (n).
+		*/
+		int dl = bd & DL, du = bd & DU, dr = bd & DR, dd = bd & DD;
+		if (dl) {
+			int p = dd ? -s : 0, n = du ? -s : dd ? s : 0;
+			XftDrawRect(xd, fg, x, y + h2 + s, w2 + s + p, s);
+			XftDrawRect(xd, fg, x, y + h2 - s, w2 + s + n, s);
+		}
+		if (du) {
+			int p = dl ? -s : 0, n = dr ? -s : dl ? s : 0;
+			XftDrawRect(xd, fg, x + w2 - s, y, s, h2 + s + p);
+			XftDrawRect(xd, fg, x + w2 + s, y, s, h2 + s + n);
+		}
+		if (dr) {
+			int p = du ? -s : 0, n = dd ? -s : du ? s : 0;
+			XftDrawRect(xd, fg, x + w2 - p, y + h2 - s, w - w2 + p, s);
+			XftDrawRect(xd, fg, x + w2 - n, y + h2 + s, w - w2 + n, s);
+		}
+		if (dd) {
+			int p = dr ? -s : 0, n = dl ? -s : dr ? s : 0;
+			XftDrawRect(xd, fg, x + w2 + s, y + h2 - p, s, h - h2 + p);
+			XftDrawRect(xd, fg, x + w2 - s, y + h2 - n, s, h - h2 + n);
+		}
+	}
+}
diff --git a/boxdraw_data.h b/boxdraw_data.h
new file mode 100644
index 0000000..7890500
--- /dev/null
+++ b/boxdraw_data.h
@@ -0,0 +1,214 @@
+/*
+ * Copyright 2018 Avi Halachmi (:avih) avihpit@yahoo.com https://github.com/avih
+ * MIT/X Consortium License
+ */
+
+/*
+ * U+25XX codepoints data
+ *
+ * References:
+ *   http://www.unicode.org/charts/PDF/U2500.pdf
+ *   http://www.unicode.org/charts/PDF/U2580.pdf
+ *
+ * Test page:
+ *   https://github.com/GNOME/vte/blob/master/doc/boxes.txt
+ */
+
+/* Each shape is encoded as 16-bits. Higher bits are category, lower are data */
+/* Categories (mutually exclusive except BDB): */
+/* For convenience, BDL/BDA/BBS/BDB are 1 bit each, the rest are enums */
+#define BDL (1<<8)   /* Box Draw Lines (light/double/heavy) */
+#define BDA (1<<9)   /* Box Draw Arc (light) */
+
+#define BBD (1<<10)  /* Box Block Down (lower) X/8 */
+#define BBL (2<<10)  /* Box Block Left X/8 */
+#define BBU (3<<10)  /* Box Block Upper X/8 */
+#define BBR (4<<10)  /* Box Block Right X/8 */
+#define BBQ (5<<10)  /* Box Block Quadrants */
+#define BRL (6<<10)  /* Box Braille (data is lower byte of U28XX) */
+
+#define BBS (1<<14)  /* Box Block Shades */
+#define BDB (1<<15)  /* Box Draw is Bold */
+
+/* (BDL/BDA) Light/Double/Heavy x Left/Up/Right/Down/Horizontal/Vertical      */
+/* Heavy is light+double (literally drawing light+double align to form heavy) */
+#define LL (1<<0)
+#define LU (1<<1)
+#define LR (1<<2)
+#define LD (1<<3)
+#define LH (LL+LR)
+#define LV (LU+LD)
+
+#define DL (1<<4)
+#define DU (1<<5)
+#define DR (1<<6)
+#define DD (1<<7)
+#define DH (DL+DR)
+#define DV (DU+DD)
+
+#define HL (LL+DL)
+#define HU (LU+DU)
+#define HR (LR+DR)
+#define HD (LD+DD)
+#define HH (HL+HR)
+#define HV (HU+HD)
+
+/* (BBQ) Quadrants Top/Bottom x Left/Right */
+#define TL (1<<0)
+#define TR (1<<1)
+#define BL (1<<2)
+#define BR (1<<3)
+
+/* Data for U+2500 - U+259F except dashes/diagonals */
+static const unsigned short boxdata[256] = {
+	/* light lines */
+	[0x00] = BDL + LH,       /* light horizontal */
+	[0x02] = BDL + LV,       /* light vertical */
+	[0x0c] = BDL + LD + LR,  /* light down and right */
+	[0x10] = BDL + LD + LL,  /* light down and left */
+	[0x14] = BDL + LU + LR,  /* light up and right */
+	[0x18] = BDL + LU + LL,  /* light up and left */
+	[0x1c] = BDL + LV + LR,  /* light vertical and right */
+	[0x24] = BDL + LV + LL,  /* light vertical and left */
+	[0x2c] = BDL + LH + LD,  /* light horizontal and down */
+	[0x34] = BDL + LH + LU,  /* light horizontal and up */
+	[0x3c] = BDL + LV + LH,  /* light vertical and horizontal */
+	[0x74] = BDL + LL,       /* light left */
+	[0x75] = BDL + LU,       /* light up */
+	[0x76] = BDL + LR,       /* light right */
+	[0x77] = BDL + LD,       /* light down */
+
+	/* heavy [+light] lines */
+	[0x01] = BDL + HH,
+	[0x03] = BDL + HV,
+	[0x0d] = BDL + HR + LD,
+	[0x0e] = BDL + HD + LR,
+	[0x0f] = BDL + HD + HR,
+	[0x11] = BDL + HL + LD,
+	[0x12] = BDL + HD + LL,
+	[0x13] = BDL + HD + HL,
+	[0x15] = BDL + HR + LU,
+	[0x16] = BDL + HU + LR,
+	[0x17] = BDL + HU + HR,
+	[0x19] = BDL + HL + LU,
+	[0x1a] = BDL + HU + LL,
+	[0x1b] = BDL + HU + HL,
+	[0x1d] = BDL + HR + LV,
+	[0x1e] = BDL + HU + LD + LR,
+	[0x1f] = BDL + HD + LR + LU,
+	[0x20] = BDL + HV + LR,
+	[0x21] = BDL + HU + HR + LD,
+	[0x22] = BDL + HD + HR + LU,
+	[0x23] = BDL + HV + HR,
+	[0x25] = BDL + HL + LV,
+	[0x26] = BDL + HU + LD + LL,
+	[0x27] = BDL + HD + LU + LL,
+	[0x28] = BDL + HV + LL,
+	[0x29] = BDL + HU + HL + LD,
+	[0x2a] = BDL + HD + HL + LU,
+	[0x2b] = BDL + HV + HL,
+	[0x2d] = BDL + HL + LD + LR,
+	[0x2e] = BDL + HR + LL + LD,
+	[0x2f] = BDL + HH + LD,
+	[0x30] = BDL + HD + LH,
+	[0x31] = BDL + HD + HL + LR,
+	[0x32] = BDL + HR + HD + LL,
+	[0x33] = BDL + HH + HD,
+	[0x35] = BDL + HL + LU + LR,
+	[0x36] = BDL + HR + LU + LL,
+	[0x37] = BDL + HH + LU,
+	[0x38] = BDL + HU + LH,
+	[0x39] = BDL + HU + HL + LR,
+	[0x3a] = BDL + HU + HR + LL,
+	[0x3b] = BDL + HH + HU,
+	[0x3d] = BDL + HL + LV + LR,
+	[0x3e] = BDL + HR + LV + LL,
+	[0x3f] = BDL + HH + LV,
+	[0x40] = BDL + HU + LH + LD,
+	[0x41] = BDL + HD + LH + LU,
+	[0x42] = BDL + HV + LH,
+	[0x43] = BDL + HU + HL + LD + LR,
+	[0x44] = BDL + HU + HR + LD + LL,
+	[0x45] = BDL + HD + HL + LU + LR,
+	[0x46] = BDL + HD + HR + LU + LL,
+	[0x47] = BDL + HH + HU + LD,
+	[0x48] = BDL + HH + HD + LU,
+	[0x49] = BDL + HV + HL + LR,
+	[0x4a] = BDL + HV + HR + LL,
+	[0x4b] = BDL + HV + HH,
+	[0x78] = BDL + HL,
+	[0x79] = BDL + HU,
+	[0x7a] = BDL + HR,
+	[0x7b] = BDL + HD,
+	[0x7c] = BDL + HR + LL,
+	[0x7d] = BDL + HD + LU,
+	[0x7e] = BDL + HL + LR,
+	[0x7f] = BDL + HU + LD,
+
+	/* double [+light] lines */
+	[0x50] = BDL + DH,
+	[0x51] = BDL + DV,
+	[0x52] = BDL + DR + LD,
+	[0x53] = BDL + DD + LR,
+	[0x54] = BDL + DR + DD,
+	[0x55] = BDL + DL + LD,
+	[0x56] = BDL + DD + LL,
+	[0x57] = BDL + DL + DD,
+	[0x58] = BDL + DR + LU,
+	[0x59] = BDL + DU + LR,
+	[0x5a] = BDL + DU + DR,
+	[0x5b] = BDL + DL + LU,
+	[0x5c] = BDL + DU + LL,
+	[0x5d] = BDL + DL + DU,
+	[0x5e] = BDL + DR + LV,
+	[0x5f] = BDL + DV + LR,
+	[0x60] = BDL + DV + DR,
+	[0x61] = BDL + DL + LV,
+	[0x62] = BDL + DV + LL,
+	[0x63] = BDL + DV + DL,
+	[0x64] = BDL + DH + LD,
+	[0x65] = BDL + DD + LH,
+	[0x66] = BDL + DD + DH,
+	[0x67] = BDL + DH + LU,
+	[0x68] = BDL + DU + LH,
+	[0x69] = BDL + DH + DU,
+	[0x6a] = BDL + DH + LV,
+	[0x6b] = BDL + DV + LH,
+	[0x6c] = BDL + DH + DV,
+
+	/* (light) arcs */
+	[0x6d] = BDA + LD + LR,
+	[0x6e] = BDA + LD + LL,
+	[0x6f] = BDA + LU + LL,
+	[0x70] = BDA + LU + LR,
+
+	/* Lower (Down) X/8 block (data is 8 - X) */
+	[0x81] = BBD + 7, [0x82] = BBD + 6, [0x83] = BBD + 5, [0x84] = BBD + 4,
+	[0x85] = BBD + 3, [0x86] = BBD + 2, [0x87] = BBD + 1, [0x88] = BBD + 0,
+
+	/* Left X/8 block (data is X) */
+	[0x89] = BBL + 7, [0x8a] = BBL + 6, [0x8b] = BBL + 5, [0x8c] = BBL + 4,
+	[0x8d] = BBL + 3, [0x8e] = BBL + 2, [0x8f] = BBL + 1,
+
+	/* upper 1/2 (4/8), 1/8 block (X), right 1/2, 1/8 block (8-X) */
+	[0x80] = BBU + 4, [0x94] = BBU + 1,
+	[0x90] = BBR + 4, [0x95] = BBR + 7,
+
+	/* Quadrants */
+	[0x96] = BBQ + BL,
+	[0x97] = BBQ + BR,
+	[0x98] = BBQ + TL,
+	[0x99] = BBQ + TL + BL + BR,
+	[0x9a] = BBQ + TL + BR,
+	[0x9b] = BBQ + TL + TR + BL,
+	[0x9c] = BBQ + TL + TR + BR,
+	[0x9d] = BBQ + TR,
+	[0x9e] = BBQ + BL + TR,
+	[0x9f] = BBQ + BL + TR + BR,
+
+	/* Shades, data is an alpha value in 25% units (1/4, 1/2, 3/4) */
+	[0x91] = BBS + 1, [0x92] = BBS + 2, [0x93] = BBS + 3,
+
+	/* U+2504 - U+250B, U+254C - U+254F: unsupported (dashes) */
+	/* U+2571 - U+2573: unsupported (diagonals) */
+};
diff --git a/config.def.h b/config.def.h
index 6f05dce..85dd7b6 100644
--- a/config.def.h
+++ b/config.def.h
@@ -56,6 +56,12 @@ int allowwindowops = 0;
 static double minlatency = 8;
 static double maxlatency = 33;

+/*
+ * Synchronized-Update timeout in ms
+ * https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
+ */
+static uint su_timeout = 200;
+
 /*
  * blinking timeout (set to 0 to disable blinking) for the terminal blinking
  * attribute.
@@ -67,6 +73,18 @@ static unsigned int blinktimeout = 800;
  */
 static unsigned int cursorthickness = 2;

+/*
+ * 1: render most of the lines/blocks characters without using the font for
+ *    perfect alignment between cells (U2500 - U259F except dashes/diagonals).
+ *    Bold affects lines thickness if boxdraw_bold is not 0. Italic is ignored.
+ * 0: disable (render all U25XX glyphs normally from the font).
+ */
+const int boxdraw = 0;
+const int boxdraw_bold = 0;
+
+/* braille (U28XX):  1: render as adjacent "pixels",  0: use font */
+const int boxdraw_braille = 0;
+
 /*
  * bell volume. It must be a value between -100 and 100. Use 0 for disabling
  * it
@@ -148,6 +166,13 @@ static unsigned int cursorshape = 2;
 static unsigned int cols = 80;
 static unsigned int rows = 24;

+/*
+ * Default width and height (including borders!)
+ */
+
+static unsigned int width = 564;
+static unsigned int height = 364;
+
 /*
  * Default colour and shape of the mouse cursor
  */
@@ -199,6 +224,10 @@ 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} },
+	{ ShiftMask,            XK_l,           copyurl,        {.i =  0} },
+	{ ShiftMask,            XK_o,           opencopied,     {.v = "xdg-open"} },
 };

 /*
diff --git a/config.h b/config.h
new file mode 100644
index 0000000..c389c35
--- /dev/null
+++ b/config.h
@@ -0,0 +1,502 @@
+/* See LICENSE file for copyright and license details. */
+
+/*
+ * appearance
+ *
+ * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
+ */
+static char *font = "Cousine:size=12";
+static int borderpx = 2;
+
+/*
+ * What program is execed by st depends of these precedence rules:
+ * 1: program passed with -e
+ * 2: scroll and/or utmp
+ * 3: SHELL environment variable
+ * 4: value of shell in /etc/passwd
+ * 5: value of shell in config.h
+ */
+static char *shell = "/bin/ksh";
+char *utmp = NULL;
+/* scroll program: to enable use a string like "scroll" */
+char *scroll = NULL;
+char *stty_args = "stty raw pass8 nl -echo -iexten -cstopb 38400";
+
+/* identification sequence returned in DA and DECID */
+char *vtiden = "\033[?6c";
+
+/* Kerning / character bounding-box multipliers */
+static float cwscale = 1.0;
+static float chscale = 1.0;
+
+/*
+ * word delimiter string
+ *
+ * More advanced example: L" `'\"()[]{}"
+ */
+wchar_t *worddelimiters = L" `'\"()[]{}";
+
+/* selection timeouts (in milliseconds) */
+static unsigned int doubleclicktimeout = 300;
+static unsigned int tripleclicktimeout = 600;
+
+/* alt screens */
+int allowaltscreen = 1;
+
+/* allow certain non-interactive (insecure) window operations such as:
+   setting the clipboard text */
+int allowwindowops = 0;
+
+/*
+ * draw latency range in ms - from new content/keypress/etc until drawing.
+ * within this range, st draws when content stops arriving (idle). mostly it's
+ * near minlatency, but it waits longer for slow updates to avoid partial draw.
+ * low minlatency will tear/flicker more, as it can "detect" idle too early.
+ */
+static double minlatency = 8;
+static double maxlatency = 33;
+
+/*
+ * Synchronized-Update timeout in ms
+ * https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec
+ */
+static uint su_timeout = 200;
+
+/*
+ * blinking timeout (set to 0 to disable blinking) for the terminal blinking
+ * attribute.
+ */
+static unsigned int blinktimeout = 800;
+
+/*
+ * thickness of underline and bar cursors
+ */
+static unsigned int cursorthickness = 2;
+
+/*
+ * 1: render most of the lines/blocks characters without using the font for
+ *    perfect alignment between cells (U2500 - U259F except dashes/diagonals).
+ *    Bold affects lines thickness if boxdraw_bold is not 0. Italic is ignored.
+ * 0: disable (render all U25XX glyphs normally from the font).
+ */
+const int boxdraw = 1;
+const int boxdraw_bold = 1;
+
+/* braille (U28XX):  1: render as adjacent "pixels",  0: use font */
+const int boxdraw_braille = 1;
+
+/*
+ * bell volume. It must be a value between -100 and 100. Use 0 for disabling
+ * it
+ */
+static int bellvolume = 0;
+
+/* default TERM value */
+char *termname = "st-256color";
+
+/*
+ * spaces per tab
+ *
+ * When you are changing this value, don't forget to adapt the »it« value in
+ * the st.info and appropriately install the st.info in the environment where
+ * you use this st version.
+ *
+ *	it#$tabspaces,
+ *
+ * Secondly make sure your kernel is not expanding tabs. When running `stty
+ * -a` »tab0« should appear. You can tell the terminal to not expand tabs by
+ *  running following command:
+ *
+ *	stty tabs
+ */
+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",
+
+	/* 8 bright colors */
+	"gray50",
+	"red",
+	"green",
+	"yellow",
+	"#5c5cff",
+	"magenta",
+	"cyan",
+	"white",
+
+	[255] = 0,
+
+	/* more colors can be added after 255 to use with DefaultXX */
+	"#cccccc",
+	"#555555",
+        "#121212",
+};
+
+
+/*
+ * Default colors (colorname index)
+ * foreground, background, cursor, reverse cursor
+ */
+unsigned int defaultfg = 7;
+unsigned int defaultbg = 258;
+static unsigned int defaultcs = 256;
+static unsigned int defaultrcs = 257;
+
+/*
+ * Default shape of cursor
+ * 2: Block ("█")
+ * 4: Underline ("_")
+ * 6: Bar ("|")
+ * 7: Snowman ("☃")
+ */
+static unsigned int cursorshape = 2;
+
+/*
+ * Default columns and rows numbers
+ */
+
+static unsigned int cols = 80;
+static unsigned int rows = 24;
+
+/*
+ * Default width and height (including borders!)
+ */
+
+static unsigned int width = 564;
+static unsigned int height = 364;
+
+/*
+ * Default colour and shape of the mouse cursor
+ */
+static unsigned int mouseshape = XC_xterm;
+static unsigned int mousefg = 7;
+static unsigned int mousebg = 0;
+
+/*
+ * Color used to display font attributes when fontconfig selected a font which
+ * doesn't match the ones requested.
+ */
+static unsigned int defaultattr = 11;
+
+/*
+ * Force mouse select/shortcuts while mask is active (when MODE_MOUSE is set).
+ * Note that if you want to use ShiftMask with selmasks, set this to an other
+ * modifier, set to 0 to not use it.
+ */
+static uint forcemousemod = ShiftMask;
+
+/*
+ * Internal mouse shortcuts.
+ * Beware that overloading Button1 will disable the selection.
+ */
+static MouseShortcut mshortcuts[] = {
+	/* mask                 button   function        argument       release */
+	{ XK_ANY_MOD,           Button2, selpaste,       {.i = 0},      1 },
+	{ ShiftMask,            Button4, ttysend,        {.s = "\033[5;2~"} },
+	{ XK_ANY_MOD,           Button4, ttysend,        {.s = "\031"} },
+	{ ShiftMask,            Button5, ttysend,        {.s = "\033[6;2~"} },
+	{ XK_ANY_MOD,           Button5, ttysend,        {.s = "\005"} },
+};
+
+/* Internal keyboard shortcuts. */
+#define MODKEY Mod1Mask
+#define TERMMOD (ControlMask|ShiftMask)
+
+static Shortcut shortcuts[] = {
+	/* mask                 keysym          function        argument */
+	{ XK_ANY_MOD,           XK_Break,       sendbreak,      {.i =  0} },
+	{ 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_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} },
+	{ ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
+	{ ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
+	{ ControlMask,          XK_i,           copyurl,        {.i =  0} },
+	{ ControlMask,          XK_o,           opencopied,     {.v = "luakit"} }
+};
+
+/*
+ * Special keys (change & recompile st.info accordingly)
+ *
+ * Mask value:
+ * * Use XK_ANY_MOD to match the key no matter modifiers state
+ * * Use XK_NO_MOD to match the key alone (no modifiers)
+ * appkey value:
+ * * 0: no value
+ * * > 0: keypad application mode enabled
+ * *   = 2: term.numlock = 1
+ * * < 0: keypad application mode disabled
+ * appcursor value:
+ * * 0: no value
+ * * > 0: cursor application mode enabled
+ * * < 0: cursor application mode disabled
+ *
+ * Be careful with the order of the definitions because st searches in
+ * this table sequentially, so any XK_ANY_MOD must be in the last
+ * position for a key.
+ */
+
+/*
+ * If you want keys other than the X11 function keys (0xFD00 - 0xFFFF)
+ * to be mapped below, add them to this array.
+ */
+static KeySym mappedkeys[] = { -1 };
+
+/*
+ * State bits to ignore when matching key or button events.  By default,
+ * numlock (Mod2Mask) and keyboard layout (XK_SWITCH_MOD) are ignored.
+ */
+static uint ignoremod = Mod2Mask|XK_SWITCH_MOD;
+
+/*
+ * This is the huge key array which defines all compatibility to the Linux
+ * world. Please decide about changes wisely.
+ */
+static Key key[] = {
+	/* keysym           mask            string      appkey appcursor */
+	{ XK_KP_Home,       ShiftMask,      "\033[2J",       0,   -1},
+	{ XK_KP_Home,       ShiftMask,      "\033[1;2H",     0,   +1},
+	{ XK_KP_Home,       XK_ANY_MOD,     "\033[H",        0,   -1},
+	{ XK_KP_Home,       XK_ANY_MOD,     "\033[1~",       0,   +1},
+	{ XK_KP_Up,         XK_ANY_MOD,     "\033Ox",       +1,    0},
+	{ XK_KP_Up,         XK_ANY_MOD,     "\033[A",        0,   -1},
+	{ XK_KP_Up,         XK_ANY_MOD,     "\033OA",        0,   +1},
+	{ XK_KP_Down,       XK_ANY_MOD,     "\033Or",       +1,    0},
+	{ XK_KP_Down,       XK_ANY_MOD,     "\033[B",        0,   -1},
+	{ XK_KP_Down,       XK_ANY_MOD,     "\033OB",        0,   +1},
+	{ XK_KP_Left,       XK_ANY_MOD,     "\033Ot",       +1,    0},
+	{ XK_KP_Left,       XK_ANY_MOD,     "\033[D",        0,   -1},
+	{ XK_KP_Left,       XK_ANY_MOD,     "\033OD",        0,   +1},
+	{ XK_KP_Right,      XK_ANY_MOD,     "\033Ov",       +1,    0},
+	{ XK_KP_Right,      XK_ANY_MOD,     "\033[C",        0,   -1},
+	{ XK_KP_Right,      XK_ANY_MOD,     "\033OC",        0,   +1},
+	{ XK_KP_Prior,      ShiftMask,      "\033[5;2~",     0,    0},
+	{ XK_KP_Prior,      XK_ANY_MOD,     "\033[5~",       0,    0},
+	{ XK_KP_Begin,      XK_ANY_MOD,     "\033[E",        0,    0},
+	{ XK_KP_End,        ControlMask,    "\033[J",       -1,    0},
+	{ XK_KP_End,        ControlMask,    "\033[1;5F",    +1,    0},
+	{ XK_KP_End,        ShiftMask,      "\033[K",       -1,    0},
+	{ XK_KP_End,        ShiftMask,      "\033[1;2F",    +1,    0},
+	{ XK_KP_End,        XK_ANY_MOD,     "\033[4~",       0,    0},
+	{ XK_KP_Next,       ShiftMask,      "\033[6;2~",     0,    0},
+	{ XK_KP_Next,       XK_ANY_MOD,     "\033[6~",       0,    0},
+	{ XK_KP_Insert,     ShiftMask,      "\033[2;2~",    +1,    0},
+	{ XK_KP_Insert,     ShiftMask,      "\033[4l",      -1,    0},
+	{ XK_KP_Insert,     ControlMask,    "\033[L",       -1,    0},
+	{ XK_KP_Insert,     ControlMask,    "\033[2;5~",    +1,    0},
+	{ XK_KP_Insert,     XK_ANY_MOD,     "\033[4h",      -1,    0},
+	{ XK_KP_Insert,     XK_ANY_MOD,     "\033[2~",      +1,    0},
+	{ XK_KP_Delete,     ControlMask,    "\033[M",       -1,    0},
+	{ XK_KP_Delete,     ControlMask,    "\033[3;5~",    +1,    0},
+	{ XK_KP_Delete,     ShiftMask,      "\033[2K",      -1,    0},
+	{ XK_KP_Delete,     ShiftMask,      "\033[3;2~",    +1,    0},
+	{ XK_KP_Delete,     XK_ANY_MOD,     "\033[P",       -1,    0},
+	{ XK_KP_Delete,     XK_ANY_MOD,     "\033[3~",      +1,    0},
+	{ XK_KP_Multiply,   XK_ANY_MOD,     "\033Oj",       +2,    0},
+	{ XK_KP_Add,        XK_ANY_MOD,     "\033Ok",       +2,    0},
+	{ XK_KP_Enter,      XK_ANY_MOD,     "\033OM",       +2,    0},
+	{ XK_KP_Enter,      XK_ANY_MOD,     "\r",           -1,    0},
+	{ XK_KP_Subtract,   XK_ANY_MOD,     "\033Om",       +2,    0},
+	{ XK_KP_Decimal,    XK_ANY_MOD,     "\033On",       +2,    0},
+	{ XK_KP_Divide,     XK_ANY_MOD,     "\033Oo",       +2,    0},
+	{ XK_KP_0,          XK_ANY_MOD,     "\033Op",       +2,    0},
+	{ XK_KP_1,          XK_ANY_MOD,     "\033Oq",       +2,    0},
+	{ XK_KP_2,          XK_ANY_MOD,     "\033Or",       +2,    0},
+	{ XK_KP_3,          XK_ANY_MOD,     "\033Os",       +2,    0},
+	{ XK_KP_4,          XK_ANY_MOD,     "\033Ot",       +2,    0},
+	{ XK_KP_5,          XK_ANY_MOD,     "\033Ou",       +2,    0},
+	{ XK_KP_6,          XK_ANY_MOD,     "\033Ov",       +2,    0},
+	{ XK_KP_7,          XK_ANY_MOD,     "\033Ow",       +2,    0},
+	{ XK_KP_8,          XK_ANY_MOD,     "\033Ox",       +2,    0},
+	{ XK_KP_9,          XK_ANY_MOD,     "\033Oy",       +2,    0},
+	{ XK_Up,            ShiftMask,      "\033[1;2A",     0,    0},
+	{ XK_Up,            Mod1Mask,       "\033[1;3A",     0,    0},
+	{ XK_Up,         ShiftMask|Mod1Mask,"\033[1;4A",     0,    0},
+	{ XK_Up,            ControlMask,    "\033[1;5A",     0,    0},
+	{ XK_Up,      ShiftMask|ControlMask,"\033[1;6A",     0,    0},
+	{ XK_Up,       ControlMask|Mod1Mask,"\033[1;7A",     0,    0},
+	{ XK_Up,ShiftMask|ControlMask|Mod1Mask,"\033[1;8A",  0,    0},
+	{ XK_Up,            XK_ANY_MOD,     "\033[A",        0,   -1},
+	{ XK_Up,            XK_ANY_MOD,     "\033OA",        0,   +1},
+	{ XK_Down,          ShiftMask,      "\033[1;2B",     0,    0},
+	{ XK_Down,          Mod1Mask,       "\033[1;3B",     0,    0},
+	{ XK_Down,       ShiftMask|Mod1Mask,"\033[1;4B",     0,    0},
+	{ XK_Down,          ControlMask,    "\033[1;5B",     0,    0},
+	{ XK_Down,    ShiftMask|ControlMask,"\033[1;6B",     0,    0},
+	{ XK_Down,     ControlMask|Mod1Mask,"\033[1;7B",     0,    0},
+	{ XK_Down,ShiftMask|ControlMask|Mod1Mask,"\033[1;8B",0,    0},
+	{ XK_Down,          XK_ANY_MOD,     "\033[B",        0,   -1},
+	{ XK_Down,          XK_ANY_MOD,     "\033OB",        0,   +1},
+	{ XK_Left,          ShiftMask,      "\033[1;2D",     0,    0},
+	{ XK_Left,          Mod1Mask,       "\033[1;3D",     0,    0},
+	{ XK_Left,       ShiftMask|Mod1Mask,"\033[1;4D",     0,    0},
+	{ XK_Left,          ControlMask,    "\033[1;5D",     0,    0},
+	{ XK_Left,    ShiftMask|ControlMask,"\033[1;6D",     0,    0},
+	{ XK_Left,     ControlMask|Mod1Mask,"\033[1;7D",     0,    0},
+	{ XK_Left,ShiftMask|ControlMask|Mod1Mask,"\033[1;8D",0,    0},
+	{ XK_Left,          XK_ANY_MOD,     "\033[D",        0,   -1},
+	{ XK_Left,          XK_ANY_MOD,     "\033OD",        0,   +1},
+	{ XK_Right,         ShiftMask,      "\033[1;2C",     0,    0},
+	{ XK_Right,         Mod1Mask,       "\033[1;3C",     0,    0},
+	{ XK_Right,      ShiftMask|Mod1Mask,"\033[1;4C",     0,    0},
+	{ XK_Right,         ControlMask,    "\033[1;5C",     0,    0},
+	{ XK_Right,   ShiftMask|ControlMask,"\033[1;6C",     0,    0},
+	{ XK_Right,    ControlMask|Mod1Mask,"\033[1;7C",     0,    0},
+	{ XK_Right,ShiftMask|ControlMask|Mod1Mask,"\033[1;8C",0,   0},
+	{ XK_Right,         XK_ANY_MOD,     "\033[C",        0,   -1},
+	{ XK_Right,         XK_ANY_MOD,     "\033OC",        0,   +1},
+	{ XK_ISO_Left_Tab,  ShiftMask,      "\033[Z",        0,    0},
+	{ XK_Return,        Mod1Mask,       "\033\r",        0,    0},
+	{ XK_Return,        XK_ANY_MOD,     "\r",            0,    0},
+	{ XK_Insert,        ShiftMask,      "\033[4l",      -1,    0},
+	{ XK_Insert,        ShiftMask,      "\033[2;2~",    +1,    0},
+	{ XK_Insert,        ControlMask,    "\033[L",       -1,    0},
+	{ XK_Insert,        ControlMask,    "\033[2;5~",    +1,    0},
+	{ XK_Insert,        XK_ANY_MOD,     "\033[4h",      -1,    0},
+	{ XK_Insert,        XK_ANY_MOD,     "\033[2~",      +1,    0},
+	{ XK_Delete,        ControlMask,    "\033[M",       -1,    0},
+	{ XK_Delete,        ControlMask,    "\033[3;5~",    +1,    0},
+	{ XK_Delete,        ShiftMask,      "\033[2K",      -1,    0},
+	{ XK_Delete,        ShiftMask,      "\033[3;2~",    +1,    0},
+	{ XK_Delete,        XK_ANY_MOD,     "\033[P",       -1,    0},
+	{ XK_Delete,        XK_ANY_MOD,     "\033[3~",      +1,    0},
+	{ XK_BackSpace,     XK_NO_MOD,      "\177",          0,    0},
+	{ XK_BackSpace,     Mod1Mask,       "\033\177",      0,    0},
+	{ XK_Home,          ShiftMask,      "\033[2J",       0,   -1},
+	{ XK_Home,          ShiftMask,      "\033[1;2H",     0,   +1},
+	{ XK_Home,          XK_ANY_MOD,     "\033[H",        0,   -1},
+	{ XK_Home,          XK_ANY_MOD,     "\033[1~",       0,   +1},
+	{ XK_End,           ControlMask,    "\033[J",       -1,    0},
+	{ XK_End,           ControlMask,    "\033[1;5F",    +1,    0},
+	{ XK_End,           ShiftMask,      "\033[K",       -1,    0},
+	{ XK_End,           ShiftMask,      "\033[1;2F",    +1,    0},
+	{ XK_End,           XK_ANY_MOD,     "\033[4~",       0,    0},
+	{ XK_Prior,         ControlMask,    "\033[5;5~",     0,    0},
+	{ XK_Prior,         ShiftMask,      "\033[5;2~",     0,    0},
+	{ XK_Prior,         XK_ANY_MOD,     "\033[5~",       0,    0},
+	{ XK_Next,          ControlMask,    "\033[6;5~",     0,    0},
+	{ XK_Next,          ShiftMask,      "\033[6;2~",     0,    0},
+	{ XK_Next,          XK_ANY_MOD,     "\033[6~",       0,    0},
+	{ XK_F1,            XK_NO_MOD,      "\033OP" ,       0,    0},
+	{ XK_F1, /* F13 */  ShiftMask,      "\033[1;2P",     0,    0},
+	{ XK_F1, /* F25 */  ControlMask,    "\033[1;5P",     0,    0},
+	{ XK_F1, /* F37 */  Mod4Mask,       "\033[1;6P",     0,    0},
+	{ XK_F1, /* F49 */  Mod1Mask,       "\033[1;3P",     0,    0},
+	{ XK_F1, /* F61 */  Mod3Mask,       "\033[1;4P",     0,    0},
+	{ XK_F2,            XK_NO_MOD,      "\033OQ" ,       0,    0},
+	{ XK_F2, /* F14 */  ShiftMask,      "\033[1;2Q",     0,    0},
+	{ XK_F2, /* F26 */  ControlMask,    "\033[1;5Q",     0,    0},
+	{ XK_F2, /* F38 */  Mod4Mask,       "\033[1;6Q",     0,    0},
+	{ XK_F2, /* F50 */  Mod1Mask,       "\033[1;3Q",     0,    0},
+	{ XK_F2, /* F62 */  Mod3Mask,       "\033[1;4Q",     0,    0},
+	{ XK_F3,            XK_NO_MOD,      "\033OR" ,       0,    0},
+	{ XK_F3, /* F15 */  ShiftMask,      "\033[1;2R",     0,    0},
+	{ XK_F3, /* F27 */  ControlMask,    "\033[1;5R",     0,    0},
+	{ XK_F3, /* F39 */  Mod4Mask,       "\033[1;6R",     0,    0},
+	{ XK_F3, /* F51 */  Mod1Mask,       "\033[1;3R",     0,    0},
+	{ XK_F3, /* F63 */  Mod3Mask,       "\033[1;4R",     0,    0},
+	{ XK_F4,            XK_NO_MOD,      "\033OS" ,       0,    0},
+	{ XK_F4, /* F16 */  ShiftMask,      "\033[1;2S",     0,    0},
+	{ XK_F4, /* F28 */  ControlMask,    "\033[1;5S",     0,    0},
+	{ XK_F4, /* F40 */  Mod4Mask,       "\033[1;6S",     0,    0},
+	{ XK_F4, /* F52 */  Mod1Mask,       "\033[1;3S",     0,    0},
+	{ XK_F5,            XK_NO_MOD,      "\033[15~",      0,    0},
+	{ XK_F5, /* F17 */  ShiftMask,      "\033[15;2~",    0,    0},
+	{ XK_F5, /* F29 */  ControlMask,    "\033[15;5~",    0,    0},
+	{ XK_F5, /* F41 */  Mod4Mask,       "\033[15;6~",    0,    0},
+	{ XK_F5, /* F53 */  Mod1Mask,       "\033[15;3~",    0,    0},
+	{ XK_F6,            XK_NO_MOD,      "\033[17~",      0,    0},
+	{ XK_F6, /* F18 */  ShiftMask,      "\033[17;2~",    0,    0},
+	{ XK_F6, /* F30 */  ControlMask,    "\033[17;5~",    0,    0},
+	{ XK_F6, /* F42 */  Mod4Mask,       "\033[17;6~",    0,    0},
+	{ XK_F6, /* F54 */  Mod1Mask,       "\033[17;3~",    0,    0},
+	{ XK_F7,            XK_NO_MOD,      "\033[18~",      0,    0},
+	{ XK_F7, /* F19 */  ShiftMask,      "\033[18;2~",    0,    0},
+	{ XK_F7, /* F31 */  ControlMask,    "\033[18;5~",    0,    0},
+	{ XK_F7, /* F43 */  Mod4Mask,       "\033[18;6~",    0,    0},
+	{ XK_F7, /* F55 */  Mod1Mask,       "\033[18;3~",    0,    0},
+	{ XK_F8,            XK_NO_MOD,      "\033[19~",      0,    0},
+	{ XK_F8, /* F20 */  ShiftMask,      "\033[19;2~",    0,    0},
+	{ XK_F8, /* F32 */  ControlMask,    "\033[19;5~",    0,    0},
+	{ XK_F8, /* F44 */  Mod4Mask,       "\033[19;6~",    0,    0},
+	{ XK_F8, /* F56 */  Mod1Mask,       "\033[19;3~",    0,    0},
+	{ XK_F9,            XK_NO_MOD,      "\033[20~",      0,    0},
+	{ XK_F9, /* F21 */  ShiftMask,      "\033[20;2~",    0,    0},
+	{ XK_F9, /* F33 */  ControlMask,    "\033[20;5~",    0,    0},
+	{ XK_F9, /* F45 */  Mod4Mask,       "\033[20;6~",    0,    0},
+	{ XK_F9, /* F57 */  Mod1Mask,       "\033[20;3~",    0,    0},
+	{ XK_F10,           XK_NO_MOD,      "\033[21~",      0,    0},
+	{ XK_F10, /* F22 */ ShiftMask,      "\033[21;2~",    0,    0},
+	{ XK_F10, /* F34 */ ControlMask,    "\033[21;5~",    0,    0},
+	{ XK_F10, /* F46 */ Mod4Mask,       "\033[21;6~",    0,    0},
+	{ XK_F10, /* F58 */ Mod1Mask,       "\033[21;3~",    0,    0},
+	{ XK_F11,           XK_NO_MOD,      "\033[23~",      0,    0},
+	{ XK_F11, /* F23 */ ShiftMask,      "\033[23;2~",    0,    0},
+	{ XK_F11, /* F35 */ ControlMask,    "\033[23;5~",    0,    0},
+	{ XK_F11, /* F47 */ Mod4Mask,       "\033[23;6~",    0,    0},
+	{ XK_F11, /* F59 */ Mod1Mask,       "\033[23;3~",    0,    0},
+	{ XK_F12,           XK_NO_MOD,      "\033[24~",      0,    0},
+	{ XK_F12, /* F24 */ ShiftMask,      "\033[24;2~",    0,    0},
+	{ XK_F12, /* F36 */ ControlMask,    "\033[24;5~",    0,    0},
+	{ XK_F12, /* F48 */ Mod4Mask,       "\033[24;6~",    0,    0},
+	{ XK_F12, /* F60 */ Mod1Mask,       "\033[24;3~",    0,    0},
+	{ XK_F13,           XK_NO_MOD,      "\033[1;2P",     0,    0},
+	{ XK_F14,           XK_NO_MOD,      "\033[1;2Q",     0,    0},
+	{ XK_F15,           XK_NO_MOD,      "\033[1;2R",     0,    0},
+	{ XK_F16,           XK_NO_MOD,      "\033[1;2S",     0,    0},
+	{ XK_F17,           XK_NO_MOD,      "\033[15;2~",    0,    0},
+	{ XK_F18,           XK_NO_MOD,      "\033[17;2~",    0,    0},
+	{ XK_F19,           XK_NO_MOD,      "\033[18;2~",    0,    0},
+	{ XK_F20,           XK_NO_MOD,      "\033[19;2~",    0,    0},
+	{ XK_F21,           XK_NO_MOD,      "\033[20;2~",    0,    0},
+	{ XK_F22,           XK_NO_MOD,      "\033[21;2~",    0,    0},
+	{ XK_F23,           XK_NO_MOD,      "\033[23;2~",    0,    0},
+	{ XK_F24,           XK_NO_MOD,      "\033[24;2~",    0,    0},
+	{ XK_F25,           XK_NO_MOD,      "\033[1;5P",     0,    0},
+	{ XK_F26,           XK_NO_MOD,      "\033[1;5Q",     0,    0},
+	{ XK_F27,           XK_NO_MOD,      "\033[1;5R",     0,    0},
+	{ XK_F28,           XK_NO_MOD,      "\033[1;5S",     0,    0},
+	{ XK_F29,           XK_NO_MOD,      "\033[15;5~",    0,    0},
+	{ XK_F30,           XK_NO_MOD,      "\033[17;5~",    0,    0},
+	{ XK_F31,           XK_NO_MOD,      "\033[18;5~",    0,    0},
+	{ XK_F32,           XK_NO_MOD,      "\033[19;5~",    0,    0},
+	{ XK_F33,           XK_NO_MOD,      "\033[20;5~",    0,    0},
+	{ XK_F34,           XK_NO_MOD,      "\033[21;5~",    0,    0},
+	{ XK_F35,           XK_NO_MOD,      "\033[23;5~",    0,    0},
+};
+
+/*
+ * Selection types' masks.
+ * Use the same masks as usual.
+ * Button1Mask is always unset, to make masks match between ButtonPress.
+ * ButtonRelease and MotionNotify.
+ * If no match is found, regular selection is used.
+ */
+static uint selmasks[] = {
+	[SEL_RECTANGULAR] = Mod1Mask,
+};
+
+/*
+ * Printable characters in ASCII, used to estimate the advance width
+ * of single wide characters.
+ */
+static char ascii_printable[] =
+	" !\"#$%&'()*+,-./0123456789:;<=>?"
+	"@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
+	"`abcdefghijklmnopqrstuvwxyz{|}~";
diff --git a/config.mk b/config.mk
index c070a4a..1e15105 100644
--- a/config.mk
+++ b/config.mk
@@ -26,10 +26,10 @@ STCFLAGS = $(INCS) $(STCPPFLAGS) $(CPPFLAGS) $(CFLAGS)
 STLDFLAGS = $(LIBS) $(LDFLAGS)

 # OpenBSD:
-#CPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600 -D_BSD_SOURCE
-#LIBS = -L$(X11LIB) -lm -lX11 -lutil -lXft \
-#       `$(PKG_CONFIG) --libs fontconfig` \
-#       `$(PKG_CONFIG) --libs freetype2`
+CPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600 -D_BSD_SOURCE
+LIBS = -L$(X11LIB) -lm -lX11 -lutil -lXft \
+       `$(PKG_CONFIG) --libs fontconfig` \
+       `$(PKG_CONFIG) --libs freetype2`

 # compiler and linker
 # CC = c99
diff --git a/st.c b/st.c
index a9338e1..0fe6105 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      12000

 /* 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 */
@@ -184,8 +191,8 @@ 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);
@@ -200,6 +207,8 @@ static void tdefutf8(char);
 static int32_t tdefcolor(const int *, int *, int);
 static void tdeftran(char);
 static void tstrsequence(uchar);
+static void tsetcolor(int, int, int, uint32_t, uint32_t);
+static char * findlastany(char *, const char**, size_t);

 static void drawregion(int, int, int, int);

@@ -231,6 +240,33 @@ static const uchar utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
 static const Rune utfmin[UTF_SIZ + 1] = {       0,    0,  0x80,  0x800,  0x10000};
 static const Rune utfmax[UTF_SIZ + 1] = {0x10FFFF, 0x7F, 0x7FF, 0xFFFF, 0x10FFFF};

+#include <time.h>
+static int su = 0;
+struct timespec sutv;
+
+static void
+tsync_begin()
+{
+	clock_gettime(CLOCK_MONOTONIC, &sutv);
+	su = 1;
+}
+
+static void
+tsync_end()
+{
+	su = 0;
+}
+
+int
+tinsync(uint timeout)
+{
+	struct timespec now;
+	if (su && !clock_gettime(CLOCK_MONOTONIC, &now)
+	       && TIMEDIFF(now, sutv) >= timeout)
+		su = 0;
+	return su;
+}
+
 ssize_t
 xwrite(int fd, const char *s, size_t len)
 {
@@ -416,10 +452,10 @@ 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;
@@ -528,7 +564,7 @@ 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 +579,14 @@ 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 +607,14 @@ 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 +645,13 @@ 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;

@@ -810,7 +846,7 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 		break;
 	default:
 #ifdef __OpenBSD__
-		if (pledge("stdio rpath tty proc", NULL) == -1)
+		if (pledge("stdio rpath tty proc exec", NULL) == -1)
 			die("pledge\n");
 #endif
 		close(s);
@@ -821,6 +857,9 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 	return cmdfd;
 }

+static int twrite_aborted = 0;
+int ttyread_pending() { return twrite_aborted; }
+
 size_t
 ttyread(void)
 {
@@ -829,7 +868,7 @@ ttyread(void)
 	int ret, written;

 	/* append read bytes to unprocessed bytes */
-	ret = read(cmdfd, buf+buflen, LEN(buf)-buflen);
+	ret = twrite_aborted ? 1 : read(cmdfd, buf+buflen, LEN(buf)-buflen);

 	switch (ret) {
 	case 0:
@@ -837,7 +876,7 @@ ttyread(void)
 	case -1:
 		die("couldn't read from shell: %s\n", strerror(errno));
 	default:
-		buflen += ret;
+		buflen += twrite_aborted ? 0 : ret;
 		written = twrite(buf, buflen, 0);
 		buflen -= written;
 		/* keep any incomplete UTF-8 byte sequence for the next call */
@@ -851,6 +890,9 @@ 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);
@@ -997,6 +1039,7 @@ tsetdirtattr(int attr)
 void
 tfulldirt(void)
 {
+	tsync_end();
 	tsetdirt(0, term.row-1);
 }

@@ -1062,13 +1105,53 @@ 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);

@@ -1078,17 +1161,28 @@ 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);

@@ -1098,7 +1192,8 @@ tscrollup(int orig, int n)
 		term.line[i+n] = temp;
 	}

-	selscroll(orig, -n);
+	if (term.scr == 0)
+		selscroll(orig, -n);
 }

 void
@@ -1127,7 +1222,7 @@ tnewline(int first_col)
 	int y = term.c.y;

 	if (y == term.bot) {
-		tscrollup(term.top, 1);
+		tscrollup(term.top, 1, 1);
 	} else {
 		y++;
 	}
@@ -1222,6 +1317,9 @@ tsetchar(Rune u, const Glyph *attr, int x, int y)
 	term.dirty[y] = 1;
 	term.line[y][x] = *attr;
 	term.line[y][x].u = u;
+
+	if (isboxdraw(u))
+		term.line[y][x].mode |= ATTR_BOXDRAW;
 }

 void
@@ -1292,14 +1390,14 @@ 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
@@ -1736,11 +1834,11 @@ csihandle(void)
 		break;
 	case 'S': /* SU -- Scroll <n> line up */
 		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);
@@ -1893,10 +1991,8 @@ strhandle(void)
 				fprintf(stderr, "erresc: invalid color j=%d, p=%s\n",
 				        j, p ? p : "(null)");
 			} else {
-				/*
-				 * TODO if defaultbg color is changed, borders
-				 * are dirty
-				 */
+				if (j == defaultbg)
+					xclearwin();
 				redraw();
 			}
 			return;
@@ -1906,6 +2002,12 @@ strhandle(void)
 		xsettitle(strescseq.args[0]);
 		return;
 	case 'P': /* DCS -- Device Control String */
+		/* https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec */
+		if (strstr(strescseq.buf, "=1s") == strescseq.buf)
+			tsync_begin();  /* BSU */
+		else if (strstr(strescseq.buf, "=2s") == strescseq.buf)
+			tsync_end();  /* ESU */
+		return;
 	case '_': /* APC -- Application Program Command */
 	case '^': /* PM -- Privacy Message */
 		return;
@@ -2252,7 +2354,7 @@ 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);
 		}
@@ -2265,7 +2367,7 @@ 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);
 		}
@@ -2447,6 +2549,9 @@ twrite(const char *buf, int buflen, int show_ctrl)
 	Rune u;
 	int n;

+	int su0 = su;
+	twrite_aborted = 0;
+
 	for (n = 0; n < buflen; n += charsize) {
 		if (IS_SET(MODE_UTF8)) {
 			/* process a complete utf8 char */
@@ -2457,6 +2562,10 @@ twrite(const char *buf, int buflen, int show_ctrl)
 			u = buf[n] & 0xFF;
 			charsize = 1;
 		}
+		if (su0 && !su) {
+			twrite_aborted = 1;
+			break;  // ESU - allow rendering before a new BSU
+		}
 		if (show_ctrl && ISCONTROL(u)) {
 			if (u & 0x80) {
 				u &= 0x7f;
@@ -2475,7 +2584,7 @@ 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;
@@ -2512,6 +2621,14 @@ 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));
@@ -2570,7 +2687,7 @@ 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);
 	}
 }

@@ -2591,8 +2708,9 @@ 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();
@@ -2606,3 +2724,122 @@ redraw(void)
 	tfulldirt();
 	draw();
 }
+
+void
+tsetcolor( int row, int start, int end, uint32_t fg, uint32_t bg )
+{
+	int i = start;
+	for( ; i < end; ++i )
+	{
+		term.line[row][i].fg = fg;
+		term.line[row][i].bg = bg;
+	}
+}
+
+char *
+findlastany(char *str, const char** find, size_t len)
+{
+	char* found = NULL;
+	int i = 0;
+	for(found = str + strlen(str) - 1; found >= str; --found) {
+		for(i = 0; i < len; i++) {
+			if(strncmp(found, find[i], strlen(find[i])) == 0) {
+				return found;
+			}
+		}
+	}
+
+	return NULL;
+}
+
+/*
+** Select and copy the previous url on screen (do nothing if there's no url).
+**
+** FIXME: doesn't handle urls that span multiple lines; will need to add support
+**        for multiline "getsel()" first
+*/
+void
+copyurl(const Arg *arg) {
+	/* () and [] can appear in urls, but excluding them here will reduce false
+	 * positives when figuring out where a given url ends.
+	 */
+	static char URLCHARS[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+		"abcdefghijklmnopqrstuvwxyz"
+		"0123456789-._~:/?#@!$&'*+,;=%";
+
+	static const char* URLSTRINGS[] = {"http://", "https://", "gopher://"};
+
+	/* remove highlighting from previous selection if any */
+	if(sel.ob.x >= 0 && sel.oe.x >= 0)
+		tsetcolor(sel.nb.y, sel.ob.x, sel.oe.x + 1, defaultfg, defaultbg);
+
+	int i = 0,
+		row = 0, /* row of current URL */
+		col = 0, /* column of current URL start */
+		startrow = 0, /* row of last occurrence */
+		colend = 0, /* column of last occurrence */
+		passes = 0; /* how many rows have been scanned */
+
+	char *linestr = calloc(term.col+1, sizeof(Rune));
+	char *c = NULL,
+		 *match = NULL;
+
+	row = (sel.ob.x >= 0 && sel.nb.y > 0) ? sel.nb.y : term.bot;
+	LIMIT(row, term.top, term.bot);
+	startrow = row;
+
+	colend = (sel.ob.x >= 0 && sel.nb.y > 0) ? sel.nb.x : term.col;
+	LIMIT(colend, 0, term.col);
+
+	/*
+ 	** Scan from (term.bot,term.col) to (0,0) and find
+	** next occurrance of a URL
+	*/
+	while(passes !=term.bot + 2) {
+		/* Read in each column of every row until
+ 		** we hit previous occurrence of URL
+		*/
+		for (col = 0, i = 0; col < colend; ++col,++i) {
+			linestr[i] = term.line[row][col].u;
+		}
+		linestr[term.col] = '\0';
+
+		if ((match = findlastany(linestr, URLSTRINGS,
+						sizeof(URLSTRINGS)/sizeof(URLSTRINGS[0]))))
+			break;
+
+		if (--row < term.top)
+			row = term.bot;
+
+		colend = term.col;
+		passes++;
+	};
+
+	if (match) {
+		/* must happen before trim */
+		selclear();
+		sel.ob.x = strlen(linestr) - strlen(match);
+
+		/* trim the rest of the line from the url match */
+		for (c = match; *c != '\0'; ++c)
+			if (!strchr(URLCHARS, *c)) {
+				*c = '\0';
+				break;
+			}
+
+		/* highlight selection by inverting terminal colors */
+		tsetcolor(row, sel.ob.x, sel.ob.x + strlen( match ), defaultbg, defaultfg);
+
+		/* select and copy */
+		sel.mode = 1;
+		sel.type = SEL_REGULAR;
+		sel.oe.x = sel.ob.x + strlen(match)-1;
+		sel.ob.y = sel.oe.y = row;
+		selnormalize();
+		tsetdirt(sel.nb.y, sel.ne.y);
+		xsetsel(getsel());
+		xclipcopy();
+	}
+
+	free(linestr);
+}
diff --git a/st.h b/st.h
index fa2eddf..64f281f 100644
--- a/st.h
+++ b/st.h
@@ -33,6 +33,7 @@ enum glyph_attribute {
 	ATTR_WRAP       = 1 << 8,
 	ATTR_WIDE       = 1 << 9,
 	ATTR_WDUMMY     = 1 << 10,
+	ATTR_BOXDRAW    = 1 << 11,
 	ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
 };

@@ -81,10 +82,14 @@ void die(const char *, ...);
 void redraw(void);
 void draw(void);

+void kscrolldown(const Arg *);
+void kscrollup(const Arg *);
+void opencopied(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);
 void toggleprinter(const Arg *);
+void copyurl(const Arg *);

 int tattrset(int);
 void tnew(int, int);
@@ -111,6 +116,14 @@ void *xmalloc(size_t);
 void *xrealloc(void *, size_t);
 char *xstrdup(const char *);

+int isboxdraw(Rune);
+ushort boxdrawindex(const Glyph *);
+#ifdef XFT_VERSION
+/* only exposed to x.c, otherwise we'll need Xft.h for the types */
+void boxdraw_xinit(Display *, Colormap, XftDraw *, Visual *);
+void drawboxes(int, int, int, int, XftColor *, XftColor *, const XftGlyphFontSpec *, int);
+#endif
+
 /* config.h globals */
 extern char *utmp;
 extern char *scroll;
@@ -123,3 +136,4 @@ extern char *termname;
 extern unsigned int tabspaces;
 extern unsigned int defaultfg;
 extern unsigned int defaultbg;
+extern const int boxdraw, boxdraw_bold, boxdraw_braille;
diff --git a/st.info b/st.info
index 8201ad6..b32b446 100644
--- a/st.info
+++ b/st.info
@@ -191,6 +191,7 @@ st-mono| simpleterm monocolor,
 	Ms=\E]52;%p1%s;%p2%s\007,
 	Se=\E[2 q,
 	Ss=\E[%p1%d q,
+	Sync=\EP=%p1%ds\E\\,

 st| simpleterm,
 	use=st-mono,
diff --git a/win.h b/win.h
index e6e4369..323dfae 100644
--- a/win.h
+++ b/win.h
@@ -38,3 +38,4 @@ void xsetpointermotion(int);
 void xsetsel(char *);
 int xstartdraw(void);
 void xximspot(int, int);
+void xclearwin(void);
diff --git a/x.c b/x.c
index 89786b8..e635146 100644
--- a/x.c
+++ b/x.c
@@ -81,8 +81,10 @@ typedef XftGlyphFontSpec GlyphFontSpec;
 typedef struct {
 	int tw, th; /* tty width and height */
 	int w, h; /* window width and height */
+	int hborderpx, vborderpx;
 	int ch; /* char height */
 	int cw; /* char width  */
+	int cyo; /* char y offset */
 	int mode; /* window state/mode flags */
 	int cursor; /* cursor style */
 } TermWindow;
@@ -331,7 +333,7 @@ ttysend(const Arg *arg)
 int
 evcol(XEvent *e)
 {
-	int x = e->xbutton.x - borderpx;
+	int x = e->xbutton.x - win.hborderpx;
 	LIMIT(x, 0, win.tw - 1);
 	return x / win.cw;
 }
@@ -339,7 +341,7 @@ evcol(XEvent *e)
 int
 evrow(XEvent *e)
 {
-	int y = e->xbutton.y - borderpx;
+	int y = e->xbutton.y - win.vborderpx;
 	LIMIT(y, 0, win.th - 1);
 	return y / win.ch;
 }
@@ -723,6 +725,9 @@ cresize(int width, int height)
 	col = MAX(1, col);
 	row = MAX(1, row);

+	win.hborderpx = (win.w - col * win.cw) / 2;
+	win.vborderpx = (win.h - row * win.ch) / 2;
+
 	tresize(col, row);
 	xresize(col, row);
 	ttyresize(win.tw, win.th);
@@ -827,6 +832,12 @@ xclear(int x1, int y1, int x2, int y2)
 			x1, y1, x2-x1, y2-y1);
 }

+void
+xclearwin(void)
+{
+	xclear(0, 0, win.w, win.h);
+}
+
 void
 xhints(void)
 {
@@ -840,8 +851,8 @@ xhints(void)
 	sizeh->flags = PSize | PResizeInc | PBaseSize | PMinSize;
 	sizeh->height = win.h;
 	sizeh->width = win.w;
-	sizeh->height_inc = win.ch;
-	sizeh->width_inc = win.cw;
+	sizeh->height_inc = 1;
+	sizeh->width_inc = 1;
 	sizeh->base_height = 2 * borderpx;
 	sizeh->base_width = 2 * borderpx;
 	sizeh->min_height = win.ch + 2 * borderpx;
@@ -1002,6 +1013,7 @@ xloadfonts(const char *fontstr, double fontsize)
 	/* Setting character width and height. */
 	win.cw = ceilf(dc.font.width * cwscale);
 	win.ch = ceilf(dc.font.height * chscale);
+	win.cyo = ceilf(dc.font.height * (chscale - 1) / 2);

 	FcPatternDel(pattern, FC_SLANT);
 	FcPatternAddInteger(pattern, FC_SLANT, FC_SLANT_ITALIC);
@@ -1098,7 +1110,7 @@ xicdestroy(XIC xim, XPointer client, XPointer call)
 }

 void
-xinit(int cols, int rows)
+xinit(int w, int h)
 {
 	XGCValues gcvalues;
 	Cursor cursor;
@@ -1123,8 +1135,8 @@ xinit(int cols, int rows)
 	xloadcols();

 	/* adjust fixed window geometry */
-	win.w = 2 * borderpx + cols * win.cw;
-	win.h = 2 * borderpx + rows * win.ch;
+	win.w = 2 * win.hborderpx + 2 * borderpx + cols * win.cw;
+	win.h = 2 * win.vborderpx + 2 * borderpx + rows * win.ch;
 	if (xw.gm & XNegative)
 		xw.l += DisplayWidth(xw.dpy, xw.scr) - win.w - 2;
 	if (xw.gm & YNegative)
@@ -1208,12 +1220,14 @@ xinit(int cols, int rows)
 	xsel.xtarget = XInternAtom(xw.dpy, "UTF8_STRING", 0);
 	if (xsel.xtarget == None)
 		xsel.xtarget = XA_STRING;
+
+	boxdraw_xinit(xw.dpy, xw.cmap, xw.draw, xw.vis);
 }

 int
 xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x, int y)
 {
-	float winx = borderpx + x * win.cw, winy = borderpx + y * win.ch, xp, yp;
+	float winx = win.hborderpx + x * win.cw, winy = win.vborderpx + y * win.ch, xp, yp;
 	ushort mode, prevmode = USHRT_MAX;
 	Font *font = &dc.font;
 	int frcflags = FRC_NORMAL;
@@ -1226,7 +1240,7 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 	FcCharSet *fccharset;
 	int i, f, numspecs = 0;

-	for (i = 0, xp = winx, yp = winy + font->ascent; i < len; ++i) {
+	for (i = 0, xp = winx, yp = winy + font->ascent + win.cyo; i < len; ++i) {
 		/* Fetch rune and mode for current glyph. */
 		rune = glyphs[i].u;
 		mode = glyphs[i].mode;
@@ -1251,11 +1265,16 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 				font = &dc.bfont;
 				frcflags = FRC_BOLD;
 			}
-			yp = winy + font->ascent;
+			yp = winy + font->ascent + win.cyo;
 		}

-		/* Lookup character index with default font. */
-		glyphidx = XftCharIndex(xw.dpy, font->match, rune);
+		if (mode & ATTR_BOXDRAW) {
+			/* minor shoehorning: boxdraw uses only this ushort */
+			glyphidx = boxdrawindex(&glyphs[i]);
+		} else {
+			/* Lookup character index with default font. */
+			glyphidx = XftCharIndex(xw.dpy, font->match, rune);
+		}
 		if (glyphidx) {
 			specs[numspecs].font = font->match;
 			specs[numspecs].glyph = glyphidx;
@@ -1346,7 +1365,7 @@ void
 xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, int y)
 {
 	int charlen = len * ((base.mode & ATTR_WIDE) ? 2 : 1);
-	int winx = borderpx + x * win.cw, winy = borderpx + y * win.ch,
+	int winx = win.hborderpx + x * win.cw, winy = win.vborderpx + y * win.ch,
 	    width = charlen * win.cw;
 	Color *fg, *bg, *temp, revfg, revbg, truefg, truebg;
 	XRenderColor colfg, colbg;
@@ -1436,17 +1455,17 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i

 	/* Intelligent cleaning up of the borders. */
 	if (x == 0) {
-		xclear(0, (y == 0)? 0 : winy, borderpx,
+		xclear(0, (y == 0)? 0 : winy, win.vborderpx,
 			winy + win.ch +
-			((winy + win.ch >= borderpx + win.th)? win.h : 0));
+			((winy + win.ch >= win.vborderpx + win.th)? win.h : 0));
 	}
-	if (winx + width >= borderpx + win.tw) {
+	if (winx + width >= win.hborderpx + win.tw) {
 		xclear(winx + width, (y == 0)? 0 : winy, win.w,
-			((winy + win.ch >= borderpx + win.th)? win.h : (winy + win.ch)));
+			((winy + win.ch >= win.vborderpx + win.th)? win.h : (winy + win.ch)));
 	}
 	if (y == 0)
-		xclear(winx, 0, winx + width, borderpx);
-	if (winy + win.ch >= borderpx + win.th)
+		xclear(winx, 0, winx + width, win.vborderpx);
+	if (winy + win.ch >= win.vborderpx + win.th)
 		xclear(winx, winy + win.ch, winx + width, win.h);

 	/* Clean up the region we want to draw to. */
@@ -1459,8 +1478,12 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	r.width = width;
 	XftDrawSetClipRectangles(xw.draw, winx, winy, &r, 1);

-	/* Render the glyphs. */
-	XftDrawGlyphFontSpec(xw.draw, fg, specs, len);
+	if (base.mode & ATTR_BOXDRAW) {
+		drawboxes(winx, winy, width / len, win.ch, fg, bg, specs, len);
+	} else {
+		/* Render the glyphs. */
+		XftDrawGlyphFontSpec(xw.draw, fg, specs, len);
+	}

 	/* Render underline and strikethrough. */
 	if (base.mode & ATTR_UNDERLINE) {
@@ -1469,7 +1492,7 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	}

 	if (base.mode & ATTR_STRUCK) {
-		XftDrawRect(xw.draw, fg, winx, winy + 2 * dc.font.ascent / 3,
+		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + 2 * dc.font.ascent / 3,
 				width, 1);
 	}

@@ -1503,7 +1526,7 @@ xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
 	/*
 	 * Select the right color for the right mode.
 	 */
-	g.mode &= ATTR_BOLD|ATTR_ITALIC|ATTR_UNDERLINE|ATTR_STRUCK|ATTR_WIDE;
+	g.mode &= ATTR_BOLD|ATTR_ITALIC|ATTR_UNDERLINE|ATTR_STRUCK|ATTR_WIDE|ATTR_BOXDRAW;

 	if (IS_SET(MODE_REVERSE)) {
 		g.mode |= ATTR_REVERSE;
@@ -1540,35 +1563,35 @@ xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
 		case 3: /* Blinking Underline */
 		case 4: /* Steady Underline */
 			XftDrawRect(xw.draw, &drawcol,
-					borderpx + cx * win.cw,
-					borderpx + (cy + 1) * win.ch - \
+					win.hborderpx + cx * win.cw,
+					win.vborderpx + (cy + 1) * win.ch - \
 						cursorthickness,
 					win.cw, cursorthickness);
 			break;
 		case 5: /* Blinking bar */
 		case 6: /* Steady bar */
 			XftDrawRect(xw.draw, &drawcol,
-					borderpx + cx * win.cw,
-					borderpx + cy * win.ch,
+					win.hborderpx + cx * win.cw,
+					win.vborderpx + cy * win.ch,
 					cursorthickness, win.ch);
 			break;
 		}
 	} else {
 		XftDrawRect(xw.draw, &drawcol,
-				borderpx + cx * win.cw,
-				borderpx + cy * win.ch,
+				win.hborderpx + cx * win.cw,
+				win.vborderpx + cy * win.ch,
 				win.cw - 1, 1);
 		XftDrawRect(xw.draw, &drawcol,
-				borderpx + cx * win.cw,
-				borderpx + cy * win.ch,
+				win.hborderpx + cx * win.cw,
+				win.vborderpx + cy * win.ch,
 				1, win.ch - 1);
 		XftDrawRect(xw.draw, &drawcol,
-				borderpx + (cx + 1) * win.cw - 1,
-				borderpx + cy * win.ch,
+				win.hborderpx + (cx + 1) * win.cw - 1,
+				win.vborderpx + cy * win.ch,
 				1, win.ch - 1);
 		XftDrawRect(xw.draw, &drawcol,
-				borderpx + cx * win.cw,
-				borderpx + (cy + 1) * win.ch - 1,
+				win.hborderpx + cx * win.cw,
+				win.vborderpx + (cy + 1) * win.ch - 1,
 				win.cw, 1);
 	}
 }
@@ -1613,6 +1636,8 @@ xsettitle(char *p)
 int
 xstartdraw(void)
 {
+	if (IS_SET(MODE_VISIBLE))
+		XCopyArea(xw.dpy, xw.win, xw.buf, dc.gc, 0, 0, win.w, win.h, 0, 0);
 	return IS_SET(MODE_VISIBLE);
 }

@@ -1879,6 +1904,9 @@ resize(XEvent *e)
 	cresize(e->xconfigure.width, e->xconfigure.height);
 }

+int tinsync(uint);
+int ttyread_pending();
+
 void
 run(void)
 {
@@ -1905,6 +1933,7 @@ run(void)
 		}
 	} while (ev.type != MapNotify);

+	cresize(w, h);
 	ttyfd = ttynew(opt_line, shell, opt_io, opt_cmd);
 	cresize(w, h);

@@ -1913,7 +1942,7 @@ run(void)
 		FD_SET(ttyfd, &rfd);
 		FD_SET(xfd, &rfd);

-		if (XPending(xw.dpy))
+		if (XPending(xw.dpy) || ttyread_pending())
 			timeout = 0;  /* existing events might not set xfd */

 		seltv.tv_sec = timeout / 1E3;
@@ -1927,7 +1956,8 @@ run(void)
 		}
 		clock_gettime(CLOCK_MONOTONIC, &now);

-		if (FD_ISSET(ttyfd, &rfd))
+		int ttyin = FD_ISSET(ttyfd, &rfd) || ttyread_pending();
+		if (ttyin)
 			ttyread();

 		xev = 0;
@@ -1951,7 +1981,7 @@ run(void)
 		 * maximum latency intervals during `cat huge.txt`, and perfect
 		 * sync with periodic updates from animations/key-repeats/etc.
 		 */
-		if (FD_ISSET(ttyfd, &rfd) || xev) {
+		if (ttyin || xev) {
 			if (!drawing) {
 				trigger = now;
 				drawing = 1;
@@ -1962,6 +1992,18 @@ run(void)
 				continue;  /* we have time, try to find idle */
 		}

+		if (tinsync(su_timeout)) {
+			/*
+			 * on synchronized-update draw-suspension: don't reset
+			 * drawing so that we draw ASAP once we can (just after
+			 * ESU). it won't be too soon because we already can
+			 * draw now but we skip. we set timeout > 0 to draw on
+			 * SU-timeout even without new content.
+			 */
+			timeout = minlatency;
+			continue;
+		}
+
 		/* idle detected or maxlatency exhausted -> draw */
 		timeout = -1;
 		if (blinktimeout && tattrset(ATTR_BLINK)) {
@@ -2065,3 +2107,22 @@ run:

 	return 0;
 }
+
+void
+opencopied(const Arg *arg)
+{
+	size_t const max_cmd = 2048;
+	char * const clip = xsel.clipboard;
+	if(!clip) {
+		fprintf(stderr, "Warning: nothing copied to clipboard\n");
+		return;
+	}
+
+	/* account for space/quote (3) and \0 (1) and & (1) */
+	/* e.g.: xdg-open "https://st.suckless.org"& */
+	size_t const cmd_size = max_cmd + strlen(clip) + 5;
+	char cmd[cmd_size];
+
+	snprintf(cmd, cmd_size, "%s \"%s\" &", (char *)arg->v, clip);
+	system(cmd);
+}