Merge branch 'bump' into 'master'

Bumped to Version 0.8.3

See merge request rafa_99/st!3

16 files changed, 548 insertions, 721 deletions

diff --git a/FAQ b/FAQ
index ecf7af8..85534a4 100644
--- a/FAQ
+++ b/FAQ
@@ -1,6 +1,6 @@
 ## Why does st not handle utmp entries?
 
-Use the excellent tool of [utmp](http://git.suckless.org/utmp/) for this task.
+Use the excellent tool of [utmp](https://git.suckless.org/utmp/) for this task.
 
 ## Some _random program_ complains that st is unknown/not recognised/unsupported/whatever!
 
@@ -15,19 +15,18 @@ you can manually run `tic -sx st.info`.
 * Some programs don’t complain about the lacking st description and default to
   another terminal. In that case see the question about terminfo.
 
-## I get some weird glitches/visual bug on _random program_!
-
-Try launching it with a different TERM: $ TERM=xterm myapp. toe(1) will give
-you a list of available terminals, but you’ll most likely switch between xterm,
-st or st-256color. The default value for TERM can be changed in config.h
-(TNAME).
-
 ## How do I scroll back up?
 
-Using a terminal multiplexer.
+* Using a terminal multiplexer.
+	* `st -e tmux` using C-b [
+	* `st -e screen` using C-a ESC
+* Using the excellent tool of [scroll](https://git.suckless.org/scroll/).
+* Using the scrollback [patch](https://st.suckless.org/patches/scrollback/).
+
+## I would like to have utmp and/or scroll functionality by default
 
-* `st -e tmux` using C-b [
-* `st -e screen` using C-a ESC
+You can add the absolute patch of both programs in your config.h
+file. You only have to modify the value of utmp and scroll variables.
 
 ## Why doesn't the Del key work in some programs?
 
@@ -104,7 +103,7 @@ St is emulating the Linux way of handling backspace being delete and delete bein
 backspace.
 
 This is an issue that was discussed in suckless mailing list
-<http://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy
+<https://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy
 terminal users wants its backspace to be how he feels it:
 
 	Well, I am going to comment why I want to change the behaviour
@@ -163,7 +162,15 @@ terminal users wants its backspace to be how he feels it:
 
 Apply [1].
 
-[1] http://st.suckless.org/patches/delkey
+[1] https://st.suckless.org/patches/delkey
+
+## Why do images not work in st (in programs such as w3m)?
+
+This is a terrible hack that overdraws an image on top of the terminal emulator
+window. It also relies on a very specific way the terminal draws it's contents.
+
+A more proper (but limited way) would be using sixels. Which st doesn't
+support.
 
 ## BadLength X error in Xft when trying to render emoji
 
diff --git a/Makefile b/Makefile
index 6dfa212..38240da 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@
 
 include config.mk
 
-SRC = st.c x.c boxdraw.c
+SRC = st.c x.c hb.c
 OBJ = $(SRC:.c=.o)
 
 all: options st
@@ -22,8 +22,8 @@ config.h:
 	$(CC) $(STCFLAGS) -c $<
 
 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
+x.o: arg.h config.h st.h win.h hb.h
+hb.o: st.h
 
 $(OBJ): config.h config.mk
 
diff --git a/boxdraw.c b/boxdraw.c
deleted file mode 100644
index 28a92d0..0000000
--- a/boxdraw.c
+++ /dev/null
@@ -1,194 +0,0 @@
-/*
- * 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
deleted file mode 100644
index 7890500..0000000
--- a/boxdraw_data.h
+++ /dev/null
@@ -1,214 +0,0 @@
-/*
- * 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/colors.h b/colors.h
index 9b955c2..bc2470b 100644
--- a/colors.h
+++ b/colors.h
@@ -1,3 +1,4 @@
+/* Terminal colors (16 first used in escape sequence) */
 static const char *colorname[] = {
 	/* 8 normal colors */
 	"black",
@@ -24,4 +25,5 @@ static const char *colorname[] = {
 	/* more colors can be added after 255 to use with DefaultXX */
 	"#cccccc",
 	"#555555",
+	"black",
 };
diff --git a/config.def.h b/config.def.h
index 81ade7b..a84dd6b 100644
--- a/config.def.h
+++ b/config.def.h
@@ -17,13 +17,15 @@ static int borderpx = 2;
 /*
  * What program is execed by st depends of these precedence rules:
  * 1: program passed with -e
- * 2: utmp option
+ * 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/sh";
 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 */
@@ -47,9 +49,14 @@ static unsigned int tripleclicktimeout = 600;
 /* alt screens */
 int allowaltscreen = 1;
 
-/* frames per second st should at maximum draw to the screen */
-static unsigned int xfps = 120;
-static unsigned int actionfps = 30;
+/*
+ * 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;
 
 /*
  * blinking timeout (set to 0 to disable blinking) for the terminal blinking
@@ -63,18 +70,6 @@ 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
  */
@@ -173,13 +168,23 @@ static unsigned int mousebg = 0;
 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[] = {
-	/* button               mask            string */
-	{ Button4,              XK_ANY_MOD,     "\031" },
-	{ Button5,              XK_ANY_MOD,     "\005" },
+	/* 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. */
@@ -238,13 +243,6 @@ static KeySym mappedkeys[] = { -1 };
 static uint ignoremod = Mod2Mask|XK_SWITCH_MOD;
 
 /*
- * Override mouse-select 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 forceselmod = ShiftMask;
-
-/*
  * This is the huge key array which defines all compatibility to the Linux
  * world. Please decide about changes wisely.
  */
diff --git a/config.h b/config.h
index 0aa0a84..f5238ef 100644
--- a/config.h
+++ b/config.h
@@ -1,3 +1,4 @@
+#include "colors.h"
 /* See LICENSE file for copyright and license details. */
 
 /*
@@ -5,24 +6,26 @@
  *
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
-static char *font = "JetBrains Mono Nerd Font:size=12:antialias=true:autohint=true";
+static char *font = "JetBrains Mono Nerd Font:pixelsize=12:antialias=true:autohint=true";
 /* Spare fonts */
 static char *font2[] = {
-	"Symbola:size=12:antialias=true:autohint=true",
+	"Symbola:pixelsize=11:antialias=true:autohint=true",
 };
 
-static int borderpx = 2;
+static int borderpx = 5;
 
 /*
  * What program is execed by st depends of these precedence rules:
  * 1: program passed with -e
- * 2: utmp option
+ * 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/sh";
 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 */
@@ -46,9 +49,14 @@ static unsigned int tripleclicktimeout = 600;
 /* alt screens */
 int allowaltscreen = 1;
 
-/* frames per second st should at maximum draw to the screen */
-static unsigned int xfps = 120;
-static unsigned int actionfps = 30;
+/*
+ * 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;
 
 /*
  * blinking timeout (set to 0 to disable blinking) for the terminal blinking
@@ -62,18 +70,6 @@ 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 = 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
  */
@@ -102,17 +98,14 @@ unsigned int tabspaces = 8;
 /* bg opacity */
 float alpha = 0.8;
 
-/* Terminal colors (16 first used in escape sequence) */
-#include "colors.h"
-
 /*
  * Default colors (colorname index)
  * foreground, background, cursor, reverse cursor
  */
-unsigned int defaultfg = 257;
-unsigned int defaultbg = 0;
-static unsigned int defaultcs = 258;
-static unsigned int defaultrcs = 258;
+unsigned int defaultfg = 7;
+unsigned int defaultbg = 258;
+static unsigned int defaultcs = 256;
+static unsigned int defaultrcs = 257;
 
 /*
  * Default shape of cursor
@@ -144,13 +137,23 @@ static unsigned int mousebg = 0;
 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[] = {
-	/* button               mask            string */
-	{ Button4,              XK_ANY_MOD,     "\031" },
-	{ Button5,              XK_ANY_MOD,     "\005" },
+	/* 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. */
@@ -163,8 +166,8 @@ static Shortcut shortcuts[] = {
 	{ ControlMask,          XK_Print,       toggleprinter,  {.i =  0} },
 	{ ShiftMask,            XK_Print,       printscreen,    {.i =  0} },
 	{ XK_ANY_MOD,           XK_Print,       printsel,       {.i =  0} },
-	{ ControlMask,          XK_plus,        zoom,           {.f = +1} },
-	{ ControlMask,          XK_minus,       zoom,           {.f = -1} },
+	{ ControlMask,          XK_plus,        zoom,           {.f = +2} },
+	{ ControlMask,          XK_minus,       zoom,           {.f = -2} },
 	{ ControlMask,          XK_0,           zoomreset,      {.f =  0} },
 	{ TERMMOD,              XK_C,           clipcopy,       {.i =  0} },
 	{ TERMMOD,              XK_V,           clippaste,      {.i =  0} },
@@ -211,13 +214,6 @@ static KeySym mappedkeys[] = { -1 };
 static uint ignoremod = Mod2Mask|XK_SWITCH_MOD;
 
 /*
- * Override mouse-select 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 forceselmod = ShiftMask;
-
-/*
  * This is the huge key array which defines all compatibility to the Linux
  * world. Please decide about changes wisely.
  */
diff --git a/config.mk b/config.mk
index 1d2f0e2..07a3d14 100644
--- a/config.mk
+++ b/config.mk
@@ -1,5 +1,5 @@
 # st version
-VERSION = 0.8.2
+VERSION = 0.8.3
 
 # Customize below to fit your system
 
@@ -15,10 +15,12 @@ PKG_CONFIG = pkg-config
 # includes and libs
 INCS = -I$(X11INC) \
        `$(PKG_CONFIG) --cflags fontconfig` \
-       `$(PKG_CONFIG) --cflags freetype2`
+       `$(PKG_CONFIG) --cflags freetype2` \
+       `$(PKG_CONFIG) --cflags harfbuzz`
 LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft -lXrender\
        `$(PKG_CONFIG) --libs fontconfig` \
-       `$(PKG_CONFIG) --libs freetype2`
+       `$(PKG_CONFIG) --libs freetype2` \
+       `$(PKG_CONFIG) --libs harfbuzz`
 
 # flags
 STCPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600
diff --git a/hb.c b/hb.c
new file mode 100644
index 0000000..7df2828
--- /dev/null
+++ b/hb.c
@@ -0,0 +1,136 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <X11/Xft/Xft.h>
+#include <hb.h>
+#include <hb-ft.h>
+
+#include "st.h"
+
+void hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length);
+hb_font_t *hbfindfont(XftFont *match);
+
+typedef struct {
+	XftFont *match;
+	hb_font_t *font;
+} HbFontMatch;
+
+static int hbfontslen = 0;
+static HbFontMatch *hbfontcache = NULL;
+
+void
+hbunloadfonts()
+{
+	for (int i = 0; i < hbfontslen; i++) {
+		hb_font_destroy(hbfontcache[i].font);
+		XftUnlockFace(hbfontcache[i].match);
+	}
+
+	if (hbfontcache != NULL) {
+		free(hbfontcache);
+		hbfontcache = NULL;
+	}
+	hbfontslen = 0;
+}
+
+hb_font_t *
+hbfindfont(XftFont *match)
+{
+	for (int i = 0; i < hbfontslen; i++) {
+		if (hbfontcache[i].match == match)
+			return hbfontcache[i].font;
+	}
+
+	/* Font not found in cache, caching it now. */
+	hbfontcache = realloc(hbfontcache, sizeof(HbFontMatch) * (hbfontslen + 1));
+	FT_Face face = XftLockFace(match);
+	hb_font_t *font = hb_ft_font_create(face, NULL);
+	if (font == NULL)
+		die("Failed to load Harfbuzz font.");
+
+	hbfontcache[hbfontslen].match = match;
+	hbfontcache[hbfontslen].font = font;
+	hbfontslen += 1;
+
+	return font;
+}
+
+void
+hbtransform(XftGlyphFontSpec *specs, const Glyph *glyphs, size_t len, int x, int y)
+{
+	int start = 0, length = 1, gstart = 0;
+	hb_codepoint_t *codepoints = calloc(len, sizeof(hb_codepoint_t));
+
+	for (int idx = 1, specidx = 1; idx < len; idx++) {
+		if (glyphs[idx].mode & ATTR_WDUMMY) {
+			length += 1;
+			continue;
+		}
+
+		if (specs[specidx].font != specs[start].font || ATTRCMP(glyphs[gstart], glyphs[idx]) || selected(x + idx, y) != selected(x + gstart, y)) {
+			hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+			/* Reset the sequence. */
+			length = 1;
+			start = specidx;
+			gstart = idx;
+		} else {
+			length += 1;
+		}
+
+		specidx++;
+	}
+
+	/* EOL. */
+	hbtransformsegment(specs[start].font, glyphs, codepoints, gstart, length);
+
+	/* Apply the transformation to glyph specs. */
+	for (int i = 0, specidx = 0; i < len; i++) {
+		if (glyphs[i].mode & ATTR_WDUMMY)
+			continue;
+
+		if (codepoints[i] != specs[specidx].glyph)
+			((Glyph *)glyphs)[i].mode |= ATTR_LIGA;
+
+		specs[specidx++].glyph = codepoints[i];
+	}
+
+	free(codepoints);
+}
+
+void
+hbtransformsegment(XftFont *xfont, const Glyph *string, hb_codepoint_t *codepoints, int start, int length)
+{
+	hb_font_t *font = hbfindfont(xfont);
+	if (font == NULL)
+		return;
+
+	Rune rune;
+	ushort mode = USHRT_MAX;
+	hb_buffer_t *buffer = hb_buffer_create();
+	hb_buffer_set_direction(buffer, HB_DIRECTION_LTR);
+
+	/* Fill buffer with codepoints. */
+	for (int i = start; i < (start+length); i++) {
+		rune = string[i].u;
+		mode = string[i].mode;
+		if (mode & ATTR_WDUMMY)
+			rune = 0x0020;
+		hb_buffer_add_codepoints(buffer, &rune, 1, 0, 1);
+	}
+
+	/* Shape the segment. */
+	hb_shape(font, buffer, NULL, 0);
+
+	/* Get new glyph info. */
+	hb_glyph_info_t *info = hb_buffer_get_glyph_infos(buffer, NULL);
+
+	/* Write new codepoints. */
+	for (int i = 0; i < length; i++) {
+		hb_codepoint_t gid = info[i].codepoint;
+		codepoints[start+i] = gid;
+	}
+
+	/* Cleanup. */
+	hb_buffer_destroy(buffer);
+}
diff --git a/hb.h b/hb.h
new file mode 100644
index 0000000..b3e02d0
--- /dev/null
+++ b/hb.h
@@ -0,0 +1,7 @@
+#include <X11/Xft/Xft.h>
+#include <hb.h>
+#include <hb-ft.h>
+
+void hbunloadfonts();
+void hbtransform(XftGlyphFontSpec *, const Glyph *, size_t, int, int);
+
diff --git a/st.1 b/st.1
index e8d6059..39120b4 100644
--- a/st.1
+++ b/st.1
@@ -170,7 +170,8 @@ See the LICENSE file for the terms of redistribution.
 .SH SEE ALSO
 .BR tabbed (1),
 .BR utmp (1),
-.BR stty (1)
+.BR stty (1),
+.BR scroll (1)
 .SH BUGS
 See the TODO file in the distribution.
 
diff --git a/st.c b/st.c
index c3bca25..18cdc95 100644
--- a/st.c
+++ b/st.c
@@ -39,7 +39,7 @@
 
 /* macros */
 #define IS_SET(flag)		((term.mode & (flag)) != 0)
-#define ISCONTROLC0(c)		(BETWEEN(c, 0, 0x1f) || (c) == '\177')
+#define ISCONTROLC0(c)		(BETWEEN(c, 0, 0x1f) || (c) == 0x7f)
 #define ISCONTROLC1(c)		(BETWEEN(c, 0x80, 0x9f))
 #define ISCONTROL(c)		(ISCONTROLC0(c) || ISCONTROLC1(c))
 #define ISDELIM(u)		(u && wcschr(worddelimiters, u))
@@ -142,7 +142,7 @@ typedef struct {
 /* ESC '[' [[ [<priv>] <arg> [;]] <mode> [<mode>]] */
 typedef struct {
 	char buf[ESC_BUF_SIZ]; /* raw string */
-	int len;               /* raw string length */
+	size_t len;            /* raw string length */
 	char priv;
 	int arg[ESC_ARG_SIZ];
 	int narg;              /* nb of args */
@@ -153,8 +153,9 @@ typedef struct {
 /* ESC type [[ [<priv>] <arg> [;]] <mode>] ESC '\' */
 typedef struct {
 	char type;             /* ESC type ... */
-	char buf[STR_BUF_SIZ]; /* raw string */
-	int len;               /* raw string length */
+	char *buf;             /* allocated raw string */
+	size_t siz;            /* allocation size */
+	size_t len;            /* raw string length */
 	char *args[STR_ARG_SIZ];
 	int narg;              /* nb of args */
 } STREscape;
@@ -372,8 +373,9 @@ static const char base64_digits[] = {
 char
 base64dec_getc(const char **src)
 {
-	while (**src && !isprint(**src)) (*src)++;
-	return *((*src)++);
+	while (**src && !isprint(**src))
+		(*src)++;
+	return **src ? *((*src)++) : '=';  /* emulate padding if string ends */
 }
 
 char *
@@ -391,6 +393,10 @@ base64dec(const char *src)
 		int c = base64_digits[(unsigned char) base64dec_getc(&src)];
 		int d = base64_digits[(unsigned char) base64dec_getc(&src)];
 
+		/* invalid input. 'a' can be -1, e.g. if src is "\n" (c-str) */
+		if (a == -1 || b == -1)
+			break;
+
 		*dst++ = (a << 2) | ((b & 0x30) >> 4);
 		if (c == -1)
 			break;
@@ -635,7 +641,8 @@ getsel(void)
 		 * st.
 		 * FIXME: Fix the computer world.
 		 */
-		if ((y < sel.ne.y || lastx >= linelen) && !(last->mode & ATTR_WRAP))
+		if ((y < sel.ne.y || lastx >= linelen) &&
+		    (!(last->mode & ATTR_WRAP) || sel.type == SEL_RECTANGULAR))
 			*ptr++ = '\n';
 	}
 	*ptr = 0;
@@ -666,7 +673,7 @@ die(const char *errstr, ...)
 void
 execsh(char *cmd, char **args)
 {
-	char *sh, *prog;
+	char *sh, *prog, *arg;
 	const struct passwd *pw;
 
 	errno = 0;
@@ -680,13 +687,20 @@ execsh(char *cmd, char **args)
 	if ((sh = getenv("SHELL")) == NULL)
 		sh = (pw->pw_shell[0]) ? pw->pw_shell : cmd;
 
-	if (args)
+	if (args) {
 		prog = args[0];
-	else if (utmp)
+		arg = NULL;
+	} else if (scroll) {
+		prog = scroll;
+		arg = utmp ? utmp : sh;
+	} else if (utmp) {
 		prog = utmp;
-	else
+		arg = NULL;
+	} else {
 		prog = sh;
-	DEFAULT(args, ((char *[]) {prog, NULL}));
+		arg = NULL;
+	}
+	DEFAULT(args, ((char *[]) {prog, arg, NULL}));
 
 	unsetenv("COLUMNS");
 	unsetenv("LINES");
@@ -724,7 +738,7 @@ sigchld(int a)
 		die("child exited with status %d\n", WEXITSTATUS(stat));
 	else if (WIFSIGNALED(stat))
 		die("child terminated due to signal %d\n", WTERMSIG(stat));
-	exit(0);
+	_exit(0);
 }
 
 void
@@ -817,21 +831,26 @@ ttyread(void)
 {
 	static char buf[BUFSIZ];
 	static int buflen = 0;
-	int written;
-	int ret;
+	int ret, written;
 
 	/* append read bytes to unprocessed bytes */
-	if ((ret = read(cmdfd, buf+buflen, LEN(buf)-buflen)) < 0)
-		die("couldn't read from shell: %s\n", strerror(errno));
-	buflen += ret;
+	ret = read(cmdfd, buf+buflen, LEN(buf)-buflen);
 
-	written = twrite(buf, buflen, 0);
-	buflen -= written;
-	/* keep any uncomplete utf8 char for the next call */
-	if (buflen > 0)
-		memmove(buf, buf + written, buflen);
+	switch (ret) {
+	case 0:
+		exit(0);
+	case -1:
+		die("couldn't read from shell: %s\n", strerror(errno));
+	default:
+		buflen += ret;
+		written = twrite(buf, buflen, 0);
+		buflen -= written;
+		/* keep any incomplete UTF-8 byte sequence for the next call */
+		if (buflen > 0)
+			memmove(buf, buf + written, buflen);
+		return ret;
 
-	return ret;
+	}
 }
 
 void
@@ -1108,7 +1127,8 @@ tscrolldown(int orig, int n, int copyhist)
 		term.line[i-n] = temp;
 	}
 
-	selscroll(orig, n);
+	if (term.scr == 0)
+		selscroll(orig, n);
 }
 
 void
@@ -1138,7 +1158,8 @@ tscrollup(int orig, int n, int copyhist)
 		term.line[i+n] = temp;
 	}
 
-	selscroll(orig, -n);
+	if (term.scr == 0)
+		selscroll(orig, -n);
 }
 
 void
@@ -1147,27 +1168,17 @@ selscroll(int orig, int n)
 	if (sel.ob.x == -1)
 		return;
 
-	if (BETWEEN(sel.ob.y, orig, term.bot) || BETWEEN(sel.oe.y, orig, term.bot)) {
-		if ((sel.ob.y += n) > term.bot || (sel.oe.y += n) < term.top) {
+	if (BETWEEN(sel.nb.y, orig, term.bot) != BETWEEN(sel.ne.y, orig, term.bot)) {
+		selclear();
+	} else if (BETWEEN(sel.nb.y, orig, term.bot)) {
+		sel.ob.y += n;
+		sel.oe.y += n;
+		if (sel.ob.y < term.top || sel.ob.y > term.bot ||
+		    sel.oe.y < term.top || sel.oe.y > term.bot) {
 			selclear();
-			return;
-		}
-		if (sel.type == SEL_RECTANGULAR) {
-			if (sel.ob.y < term.top)
-				sel.ob.y = term.top;
-			if (sel.oe.y > term.bot)
-				sel.oe.y = term.bot;
 		} else {
-			if (sel.ob.y < term.top) {
-				sel.ob.y = term.top;
-				sel.ob.x = 0;
-			}
-			if (sel.oe.y > term.bot) {
-				sel.oe.y = term.bot;
-				sel.oe.x = term.col;
-			}
+			selnormalize();
 		}
-		selnormalize();
 	}
 }
 
@@ -1272,9 +1283,6 @@ tsetchar(Rune u, 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
@@ -1862,7 +1870,7 @@ csihandle(void)
 void
 csidump(void)
 {
-	int i;
+	size_t i;
 	uint c;
 
 	fprintf(stderr, "ESC[");
@@ -1980,7 +1988,7 @@ strparse(void)
 void
 strdump(void)
 {
-	int i;
+	size_t i;
 	uint c;
 
 	fprintf(stderr, "ESC%c", strescseq.type);
@@ -2007,7 +2015,10 @@ strdump(void)
 void
 strreset(void)
 {
-	memset(&strescseq, 0, sizeof(strescseq));
+	strescseq = (STREscape){
+		.buf = xrealloc(strescseq.buf, STR_BUF_SIZ),
+		.siz = STR_BUF_SIZ,
+	};
 }
 
 void
@@ -2065,7 +2076,7 @@ tdumpline(int n)
 	bp = &term.line[n][0];
 	end = &bp[MIN(tlinelen(n), term.col) - 1];
 	if (bp != end || bp->u != ' ') {
-		for ( ;bp <= end; ++bp)
+		for ( ; bp <= end; ++bp)
 			tprinter(buf, utf8encode(bp->u, buf));
 	}
 	tprinter("\n", 1);
@@ -2195,6 +2206,7 @@ tcontrolcode(uchar ascii)
 		return;
 	case '\032': /* SUB */
 		tsetchar('?', &term.c.attr, term.c.x, term.c.y);
+		/* FALLTHROUGH */
 	case '\030': /* CAN */
 		csireset();
 		break;
@@ -2349,15 +2361,13 @@ tputc(Rune u)
 	Glyph *gp;
 
 	control = ISCONTROL(u);
-	if (!IS_SET(MODE_UTF8) && !IS_SET(MODE_SIXEL)) {
+	if (u < 127 || !IS_SET(MODE_UTF8 | MODE_SIXEL)) {
 		c[0] = u;
 		width = len = 1;
 	} else {
 		len = utf8encode(u, c);
-		if (!control && (width = wcwidth(u)) == -1) {
-			memcpy(c, "\357\277\275", 4); /* UTF_INVALID */
+		if (!control && (width = wcwidth(u)) == -1)
 			width = 1;
-		}
 	}
 
 	if (IS_SET(MODE_PRINT))
@@ -2389,7 +2399,7 @@ tputc(Rune u)
 		if (term.esc&ESC_DCS && strescseq.len == 0 && u == 'q')
 			term.mode |= MODE_SIXEL;
 
-		if (strescseq.len+len >= sizeof(strescseq.buf)-1) {
+		if (strescseq.len+len >= strescseq.siz) {
 			/*
 			 * Here is a bug in terminals. If the user never sends
 			 * some code to stop the str or esc command, then st
@@ -2403,7 +2413,10 @@ tputc(Rune u)
 			 * term.esc = 0;
 			 * strhandle();
 			 */
-			return;
+			if (strescseq.siz > (SIZE_MAX - UTF_SIZ) / 2)
+				return;
+			strescseq.siz *= 2;
+			strescseq.buf = xrealloc(strescseq.buf, strescseq.siz);
 		}
 
 		memmove(&strescseq.buf[strescseq.len], c, len);
@@ -2452,7 +2465,7 @@ check_control_code:
 		 */
 		return;
 	}
-	if (sel.ob.x != -1 && BETWEEN(term.c.y, sel.ob.y, sel.oe.y))
+	if (selected(term.c.x, term.c.y))
 		selclear();
 
 	gp = &term.line[term.c.y][term.c.x];
@@ -2618,6 +2631,7 @@ void
 drawregion(int x1, int y1, int x2, int y2)
 {
 	int y;
+
 	for (y = y1; y < y2; y++) {
 		if (!term.dirty[y])
 			continue;
@@ -2630,7 +2644,7 @@ drawregion(int x1, int y1, int x2, int y2)
 void
 draw(void)
 {
-	int cx = term.c.x;
+	int cx = term.c.x, ocx = term.ocx, ocy = term.ocy;
 
 	if (!xstartdraw())
 		return;
@@ -2646,10 +2660,13 @@ draw(void)
 	drawregion(0, 0, term.col, term.row);
 	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;
+				term.ocx, term.ocy, term.line[term.ocy][term.ocx],
+				term.line[term.ocy], term.col);
+	term.ocx = cx;
+	term.ocy = term.c.y;
 	xfinishdraw();
-	xximspot(term.ocx, term.ocy);
+	if (ocx != term.ocx || ocy != term.ocy)
+		xximspot(term.ocx, term.ocy);
 }
 
 void
diff --git a/st.h b/st.h
index ab868d2..01bfb05 100644
--- a/st.h
+++ b/st.h
@@ -11,7 +11,8 @@
 #define DIVCEIL(n, d)		(((n) + ((d) - 1)) / (d))
 #define DEFAULT(a, b)		(a) = (a) ? (a) : (b)
 #define LIMIT(x, a, b)		(x) = (x) < (a) ? (a) : (x) > (b) ? (b) : (x)
-#define ATTRCMP(a, b)		((a).mode != (b).mode || (a).fg != (b).fg || \
+#define ATTRCMP(a, b)		(((a).mode & (~ATTR_WRAP) & (~ATTR_LIGA)) != ((b).mode & (~ATTR_WRAP) & (~ATTR_LIGA)) || \
+				(a).fg != (b).fg || \
 				(a).bg != (b).bg)
 #define TIMEDIFF(t1, t2)	((t1.tv_sec-t2.tv_sec)*1000 + \
 				(t1.tv_nsec-t2.tv_nsec)/1E6)
@@ -33,7 +34,7 @@ enum glyph_attribute {
 	ATTR_WRAP       = 1 << 8,
 	ATTR_WIDE       = 1 << 9,
 	ATTR_WDUMMY     = 1 << 10,
-	ATTR_BOXDRAW    = 1 << 11,
+	ATTR_LIGA       = 1 << 11,
 	ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
 };
 
@@ -75,6 +76,7 @@ typedef union {
 	uint ui;
 	float f;
 	const void *v;
+	const char *s;
 } Arg;
 
 void die(const char *, ...);
@@ -113,16 +115,9 @@ void *xmalloc(size_t);
 void *xrealloc(void *, size_t);
 char *xstrdup(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;
 extern char *stty_args;
 extern char *vtiden;
 extern wchar_t *worddelimiters;
@@ -132,4 +127,3 @@ extern unsigned int tabspaces;
 extern unsigned int defaultfg;
 extern unsigned int defaultbg;
 extern float alpha;
-extern const int boxdraw, boxdraw_bold, boxdraw_braille;
diff --git a/st.info b/st.info
index 52fc617..d0694e2 100644
--- a/st.info
+++ b/st.info
@@ -1,4 +1,4 @@
-st| simpleterm,
+st-mono| simpleterm monocolor,
 	acsc=+C\,D-A.B0E``aaffgghFiGjjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
 	am,
 	bce,
@@ -10,7 +10,7 @@ st| simpleterm,
 	civis=\E[?25l,
 	clear=\E[H\E[2J,
 	cnorm=\E[?12l\E[?25h,
-	colors#8,
+	colors#2,
 	cols#80,
 	cr=^M,
 	csr=\E[%i%p1%d;%p2%dr,
@@ -158,6 +158,7 @@ st| simpleterm,
 	rc=\E8,
 	rev=\E[7m,
 	ri=\EM,
+	rin=\E[%p1%dT,
 	ritm=\E[23m,
 	rmacs=\E(B,
 	rmcup=\E[?1049l,
@@ -168,13 +169,8 @@ st| simpleterm,
 	rs1=\Ec,
 	rs2=\E[4l\E>\E[?1034l,
 	sc=\E7,
-	setab=\E[4%p1%dm,
-	setaf=\E[3%p1%dm,
-	setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
-	setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
-	sgr0=\E[0m,
-	sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
 	sitm=\E[3m,
+	sgr0=\E[0m,
 	smacs=\E(0,
 	smcup=\E[?1049h,
 	smir=\E[4h,
@@ -189,10 +185,19 @@ st| simpleterm,
 	rmxx=\E[29m,
 	smxx=\E[9m,
 # tmux extensions, see TERMINFO EXTENSIONS in tmux(1)
-	Se,
-	Ss,
 	Tc,
 	Ms=\E]52;%p1%s;%p2%s\007,
+	Se=\E[2 q,
+	Ss=\E[%p1%d q,
+
+st| simpleterm,
+	use=st-mono,
+	colors#8,
+	setab=\E[4%p1%dm,
+	setaf=\E[3%p1%dm,
+	setb=\E[4%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
+	setf=\E[3%?%p1%{1}%=%t4%e%p1%{3}%=%t6%e%p1%{4}%=%t1%e%p1%{6}%=%t3%e%p1%d%;m,
+	sgr=%?%p9%t\E(0%e\E(B%;\E[0%?%p6%t;1%;%?%p2%t;4%;%?%p1%p3%|%t;7%;%?%p4%t;5%;%?%p7%t;8%;m,
 
 st-256color| simpleterm with 256 colors,
 	use=st,
@@ -220,3 +225,13 @@ st-meta-256color| simpleterm with meta key and 256 colors,
 	smm=\E[?1034h,
 	rs2=\E[4l\E>\E[?1034h,
 	is2=\E[4l\E>\E[?1034h,
+
+st-bs| simpleterm with backspace as backspace,
+	use=st,
+	kbs=\010,
+	kdch1=\177,
+
+st-bs-256color| simpleterm with backspace as backspace and 256colors,
+	use=st-256color,
+	kbs=\010,
+	kdch1=\177,
diff --git a/win.h b/win.h
index a6ef1b9..bc0d180 100644
--- a/win.h
+++ b/win.h
@@ -25,7 +25,7 @@ enum win_mode {
 
 void xbell(void);
 void xclipcopy(void);
-void xdrawcursor(int, int, Glyph, int, int, Glyph);
+void xdrawcursor(int, int, Glyph, int, int, Glyph, Line, int);
 void xdrawline(Line, int, int, int);
 void xfinishdraw(void);
 void xloadcols(void);
diff --git a/x.c b/x.c
index 04bcbe2..c3ff2cd 100644
--- a/x.c
+++ b/x.c
@@ -15,10 +15,11 @@
 #include <X11/Xft/Xft.h>
 #include <X11/XKBlib.h>
 
-static char *argv0;
+char *argv0;
 #include "arg.h"
 #include "st.h"
 #include "win.h"
+#include "hb.h"
 
 /* types used in config.h */
 typedef struct {
@@ -29,9 +30,11 @@ typedef struct {
 } Shortcut;
 
 typedef struct {
-	uint b;
-	uint mask;
-	char *s;
+	uint mod;
+	uint button;
+	void (*func)(const Arg *);
+	const Arg arg;
+	uint  release;
 } MouseShortcut;
 
 typedef struct {
@@ -56,6 +59,7 @@ static void selpaste(const Arg *);
 static void zoom(const Arg *);
 static void zoomabs(const Arg *);
 static void zoomreset(const Arg *);
+static void ttysend(const Arg *);
 
 /* config.h for applying patches and the configuration. */
 #include "config.h"
@@ -80,7 +84,6 @@ typedef struct {
 	int w, h; /* window width and height */
 	int ch; /* char height */
 	int cw; /* char width  */
-	int cyo; /* char y offset */
 	int mode; /* window state/mode flags */
 	int cursor; /* cursor style */
 } TermWindow;
@@ -92,8 +95,12 @@ typedef struct {
 	Drawable buf;
 	GlyphFontSpec *specbuf; /* font spec buffer used for rendering */
 	Atom xembed, wmdeletewin, netwmname, netwmpid;
-	XIM xim;
-	XIC xic;
+	struct {
+		XIM xim;
+		XIC xic;
+		XPoint spot;
+		XVaNestedList spotlist;
+	} ime;
 	Draw draw;
 	Visual *vis;
 	XSetWindowAttributes attrs;
@@ -141,9 +148,10 @@ static void xdrawglyphfontspecs(const XftGlyphFontSpec *, Glyph, int, int, int);
 static void xdrawglyph(Glyph, int, int);
 static void xclear(int, int, int, int);
 static int xgeommasktogravity(int);
-static void ximopen(Display *);
+static int ximopen(Display *);
 static void ximinstantiate(Display *, XPointer, XPointer);
 static void ximdestroy(XIM, XPointer, XPointer);
+static int xicdestroy(XIC, XPointer, XPointer);
 static void xinit(int, int);
 static void cresize(int, int);
 static void xresize(int, int);
@@ -167,6 +175,8 @@ static void kpress(XEvent *);
 static void cmessage(XEvent *);
 static void resize(XEvent *);
 static void focus(XEvent *);
+static uint buttonmask(uint);
+static int mouseaction(XEvent *, uint);
 static void brelease(XEvent *);
 static void bpress(XEvent *);
 static void bmotion(XEvent *);
@@ -318,6 +328,12 @@ zoomreset(const Arg *arg)
 	}
 }
 
+void
+ttysend(const Arg *arg)
+{
+	ttywrite(arg->s, strlen(arg->s), 1);
+}
+
 int
 evcol(XEvent *e)
 {
@@ -338,7 +354,7 @@ void
 mousesel(XEvent *e, int done)
 {
 	int type, seltype = SEL_REGULAR;
-	uint state = e->xbutton.state & ~(Button1Mask | forceselmod);
+	uint state = e->xbutton.state & ~(Button1Mask | forcemousemod);
 
 	for (type = 1; type < LEN(selmasks); ++type) {
 		if (match(selmasks[type], state)) {
@@ -414,25 +430,51 @@ mousereport(XEvent *e)
 	ttywrite(buf, len, 0);
 }
 
+uint
+buttonmask(uint button)
+{
+	return button == Button1 ? Button1Mask
+	     : button == Button2 ? Button2Mask
+	     : button == Button3 ? Button3Mask
+	     : button == Button4 ? Button4Mask
+	     : button == Button5 ? Button5Mask
+	     : 0;
+}
+
+int
+mouseaction(XEvent *e, uint release)
+{
+	MouseShortcut *ms;
+
+	/* ignore Button<N>mask for Button<N> - it's set on release */
+	uint state = e->xbutton.state & ~buttonmask(e->xbutton.button);
+
+	for (ms = mshortcuts; ms < mshortcuts + LEN(mshortcuts); ms++) {
+		if (ms->release == release &&
+		    ms->button == e->xbutton.button &&
+		    (match(ms->mod, state) ||  /* exact or forced */
+		     match(ms->mod, state & ~forcemousemod))) {
+			ms->func(&(ms->arg));
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
 void
 bpress(XEvent *e)
 {
 	struct timespec now;
-	MouseShortcut *ms;
 	int snap;
 
-	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forceselmod)) {
+	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forcemousemod)) {
 		mousereport(e);
 		return;
 	}
 
-	for (ms = mshortcuts; ms < mshortcuts + LEN(mshortcuts); ms++) {
-		if (e->xbutton.button == ms->b
-				&& match(ms->mask, e->xbutton.state)) {
-			ttywrite(ms->s, strlen(ms->s), 1);
-			return;
-		}
-	}
+	if (mouseaction(e, 0))
+		return;
 
 	if (e->xbutton.button == Button1) {
 		/*
@@ -648,21 +690,21 @@ xsetsel(char *str)
 void
 brelease(XEvent *e)
 {
-	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forceselmod)) {
+	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forcemousemod)) {
 		mousereport(e);
 		return;
 	}
 
-	if (e->xbutton.button == Button2)
-		selpaste(NULL);
-	else if (e->xbutton.button == Button1)
+	if (mouseaction(e, 1))
+		return;
+	if (e->xbutton.button == Button1)
 		mousesel(e, 1);
 }
 
 void
 bmotion(XEvent *e)
 {
-	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forceselmod)) {
+	if (IS_SET(MODE_MOUSE) && !(e->xbutton.state & forcemousemod)) {
 		mousereport(e);
 		return;
 	}
@@ -971,7 +1013,6 @@ xloadfonts(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);
@@ -1098,6 +1139,9 @@ xunloadfont(Font *f)
 void
 xunloadfonts(void)
 {
+	/* Clear Harfbuzz font cache. */
+	hbunloadfonts();
+
 	/* Free the loaded fonts in the font cache.  */
 	while (frclen > 0)
 		XftFontClose(xw.dpy, frc[--frclen].font);
@@ -1108,41 +1152,58 @@ xunloadfonts(void)
 	xunloadfont(&dc.ibfont);
 }
 
-void
+int
 ximopen(Display *dpy)
 {
-	XIMCallback destroy = { .client_data = NULL, .callback = ximdestroy };
+	XIMCallback imdestroy = { .client_data = NULL, .callback = ximdestroy };
+	XICCallback icdestroy = { .client_data = NULL, .callback = xicdestroy };
 
-	if ((xw.xim = XOpenIM(xw.dpy, NULL, NULL, NULL)) == NULL) {
-		XSetLocaleModifiers("@im=local");
-		if ((xw.xim = XOpenIM(xw.dpy, NULL, NULL, NULL)) == NULL) {
-			XSetLocaleModifiers("@im=");
-			if ((xw.xim = XOpenIM(xw.dpy, NULL, NULL, NULL)) == NULL)
-				die("XOpenIM failed. Could not open input device.\n");
-		}
+	xw.ime.xim = XOpenIM(xw.dpy, NULL, NULL, NULL);
+	if (xw.ime.xim == NULL)
+		return 0;
+
+	if (XSetIMValues(xw.ime.xim, XNDestroyCallback, &imdestroy, NULL))
+		fprintf(stderr, "XSetIMValues: "
+		                "Could not set XNDestroyCallback.\n");
+
+	xw.ime.spotlist = XVaCreateNestedList(0, XNSpotLocation, &xw.ime.spot,
+	                                      NULL);
+
+	if (xw.ime.xic == NULL) {
+		xw.ime.xic = XCreateIC(xw.ime.xim, XNInputStyle,
+		                       XIMPreeditNothing | XIMStatusNothing,
+		                       XNClientWindow, xw.win,
+		                       XNDestroyCallback, &icdestroy,
+		                       NULL);
 	}
-	if (XSetIMValues(xw.xim, XNDestroyCallback, &destroy, NULL) != NULL)
-		die("XSetIMValues failed. Could not set input method value.\n");
-	xw.xic = XCreateIC(xw.xim, XNInputStyle, XIMPreeditNothing | XIMStatusNothing,
-				XNClientWindow, xw.win, XNFocusWindow, xw.win, NULL);
-	if (xw.xic == NULL)
-		die("XCreateIC failed. Could not obtain input method.\n");
+	if (xw.ime.xic == NULL)
+		fprintf(stderr, "XCreateIC: Could not create input context.\n");
+
+	return 1;
 }
 
 void
 ximinstantiate(Display *dpy, XPointer client, XPointer call)
 {
-	ximopen(dpy);
-	XUnregisterIMInstantiateCallback(xw.dpy, NULL, NULL, NULL,
-					ximinstantiate, NULL);
+	if (ximopen(dpy))
+		XUnregisterIMInstantiateCallback(xw.dpy, NULL, NULL, NULL,
+		                                 ximinstantiate, NULL);
 }
 
 void
 ximdestroy(XIM xim, XPointer client, XPointer call)
 {
-	xw.xim = NULL;
+	xw.ime.xim = NULL;
 	XRegisterIMInstantiateCallback(xw.dpy, NULL, NULL, NULL,
-					ximinstantiate, NULL);
+	                               ximinstantiate, NULL);
+	XFree(xw.ime.spotlist);
+}
+
+int
+xicdestroy(XIC xim, XPointer client, XPointer call)
+{
+	xw.ime.xic = NULL;
+	return 1;
 }
 
 void
@@ -1221,7 +1282,10 @@ xinit(int cols, int rows)
 	xw.draw = XftDrawCreate(xw.dpy, xw.buf, xw.vis, xw.cmap);
 
 	/* input methods */
-	ximopen(xw.dpy);
+	if (!ximopen(xw.dpy)) {
+		XRegisterIMInstantiateCallback(xw.dpy, NULL, NULL, NULL,
+	                                       ximinstantiate, NULL);
+	}
 
 	/* white cursor, black outline */
 	cursor = XCreateFontCursor(xw.dpy, mouseshape);
@@ -1252,8 +1316,8 @@ xinit(int cols, int rows)
 
 	win.mode = MODE_NUMLOCK;
 	resettitle();
-	XMapWindow(xw.dpy, xw.win);
 	xhints();
+	XMapWindow(xw.dpy, xw.win);
 	XSync(xw.dpy, False);
 
 	clock_gettime(CLOCK_MONOTONIC, &xsel.tclick1);
@@ -1263,8 +1327,6 @@ 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
@@ -1283,13 +1345,13 @@ 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 + win.cyo; i < len; ++i) {
+	for (i = 0, xp = winx, yp = winy + font->ascent; i < len; ++i) {
 		/* Fetch rune and mode for current glyph. */
 		rune = glyphs[i].u;
 		mode = glyphs[i].mode;
 
 		/* Skip dummy wide-character spacing. */
-		if (mode == ATTR_WDUMMY)
+		if (mode & ATTR_WDUMMY)
 			continue;
 
 		/* Determine font for glyph if different from previous glyph. */
@@ -1308,16 +1370,11 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 				font = &dc.bfont;
 				frcflags = FRC_BOLD;
 			}
-			yp = winy + font->ascent + win.cyo;
+			yp = winy + font->ascent;
 		}
 
-		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);
-		}
+		/* Lookup character index with default font. */
+		glyphidx = XftCharIndex(xw.dpy, font->match, rune);
 		if (glyphidx) {
 			specs[numspecs].font = font->match;
 			specs[numspecs].glyph = glyphidx;
@@ -1401,6 +1458,9 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 		numspecs++;
 	}
 
+	/* Harfbuzz transformation for ligatures. */
+	hbtransform(specs, glyphs, len, x, y);
+
 	return numspecs;
 }
 
@@ -1521,21 +1581,17 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	r.width = width;
 	XftDrawSetClipRectangles(xw.draw, winx, winy, &r, 1);
 
-	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 the glyphs. */
+	XftDrawGlyphFontSpec(xw.draw, fg, specs, len);
 
 	/* Render underline and strikethrough. */
 	if (base.mode & ATTR_UNDERLINE) {
-		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + dc.font.ascent + 1,
+		XftDrawRect(xw.draw, fg, winx, winy + dc.font.ascent + 1,
 				width, 1);
 	}
 
 	if (base.mode & ATTR_STRUCK) {
-		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + 2 * dc.font.ascent / 3,
+		XftDrawRect(xw.draw, fg, winx, winy + 2 * dc.font.ascent / 3,
 				width, 1);
 	}
 
@@ -1554,14 +1610,17 @@ xdrawglyph(Glyph g, int x, int y)
 }
 
 void
-xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
+xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og, Line line, int len)
 {
 	Color drawcol;
 
 	/* remove the old cursor */
 	if (selected(ox, oy))
 		og.mode ^= ATTR_REVERSE;
-	xdrawglyph(og, ox, oy);
+
+	/* Redraw the line where cursor was previously.
+	 * It will restore the ligatures broken by the cursor. */
+	xdrawline(line, 0, oy, len);
 
 	if (IS_SET(MODE_HIDE))
 		return;
@@ -1569,7 +1628,7 @@ 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|ATTR_BOXDRAW;
+	g.mode &= ATTR_BOLD|ATTR_ITALIC|ATTR_UNDERLINE|ATTR_STRUCK|ATTR_WIDE;
 
 	if (IS_SET(MODE_REVERSE)) {
 		g.mode |= ATTR_REVERSE;
@@ -1595,8 +1654,9 @@ xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
 	/* draw the new one */
 	if (IS_SET(MODE_FOCUSED)) {
 		switch (win.cursor) {
-		case 7: /* st extension: snowman (U+2603) */
-			g.u = 0x2603;
+		case 7: /* st extension */
+			g.u = 0x2603; /* snowman (U+2603) */
+			/* FALLTHROUGH */
 		case 0: /* Blinking Block */
 		case 1: /* Blinking Block (Default) */
 		case 2: /* Steady Block */
@@ -1710,11 +1770,13 @@ xfinishdraw(void)
 void
 xximspot(int x, int y)
 {
-	XPoint spot = { borderpx + x * win.cw, borderpx + (y + 1) * win.ch };
-	XVaNestedList attr = XVaCreateNestedList(0, XNSpotLocation, &spot, NULL);
+	if (xw.ime.xic == NULL)
+		return;
 
-	XSetICValues(xw.xic, XNPreeditAttributes, attr, NULL);
-	XFree(attr);
+	xw.ime.spot.x = borderpx + x * win.cw;
+	xw.ime.spot.y = borderpx + (y + 1) * win.ch;
+
+	XSetICValues(xw.ime.xic, XNPreeditAttributes, xw.ime.spotlist, NULL);
 }
 
 void
@@ -1756,8 +1818,7 @@ xsetmode(int set, unsigned int flags)
 int
 xsetcursor(int cursor)
 {
-	DEFAULT(cursor, 1);
-	if (!BETWEEN(cursor, 0, 6))
+	if (!BETWEEN(cursor, 0, 7)) /* 7: st extension */
 		return 1;
 	win.cursor = cursor;
 	return 0;
@@ -1791,13 +1852,15 @@ focus(XEvent *ev)
 		return;
 
 	if (ev->type == FocusIn) {
-		XSetICFocus(xw.xic);
+		if (xw.ime.xic)
+			XSetICFocus(xw.ime.xic);
 		win.mode |= MODE_FOCUSED;
 		xseturgency(0);
 		if (IS_SET(MODE_FOCUS))
 			ttywrite("\033[I", 3, 0);
 	} else {
-		XUnsetICFocus(xw.xic);
+		if (xw.ime.xic)
+			XUnsetICFocus(xw.ime.xic);
 		win.mode &= ~MODE_FOCUSED;
 		if (IS_SET(MODE_FOCUS))
 			ttywrite("\033[O", 3, 0);
@@ -1852,7 +1915,7 @@ kpress(XEvent *ev)
 {
 	XKeyEvent *e = &ev->xkey;
 	KeySym ksym;
-	char buf[32], *customkey;
+	char buf[64], *customkey;
 	int len;
 	Rune c;
 	Status status;
@@ -1861,7 +1924,10 @@ kpress(XEvent *ev)
 	if (IS_SET(MODE_KBDLOCK))
 		return;
 
-	len = XmbLookupString(xw.xic, e, buf, sizeof buf, &ksym, &status);
+	if (xw.ime.xic)
+		len = XmbLookupString(xw.ime.xic, e, buf, sizeof buf, &ksym, &status);
+	else
+		len = XLookupString(e, buf, sizeof buf, &ksym, NULL);
 	/* 1. shortcuts */
 	for (bp = shortcuts; bp < shortcuts + LEN(shortcuts); bp++) {
 		if (ksym == bp->keysym && match(bp->mod, e->state)) {
@@ -1929,10 +1995,9 @@ run(void)
 	XEvent ev;
 	int w = win.w, h = win.h;
 	fd_set rfd;
-	int xfd = XConnectionNumber(xw.dpy), xev, blinkset = 0, dodraw = 0;
-	int ttyfd;
-	struct timespec drawtimeout, *tv = NULL, now, last, lastblink;
-	long deltatime;
+	int xfd = XConnectionNumber(xw.dpy), ttyfd, xev, drawing;
+	struct timespec seltv, *tv, now, lastblink, trigger;
+	double timeout;
 
 	/* Waiting for window mapping */
 	do {
@@ -1953,82 +2018,77 @@ run(void)
 	ttyfd = ttynew(opt_line, shell, opt_io, opt_cmd);
 	cresize(w, h);
 
-	clock_gettime(CLOCK_MONOTONIC, &last);
-	lastblink = last;
-
-	for (xev = actionfps;;) {
+	for (timeout = -1, drawing = 0, lastblink = (struct timespec){0};;) {
 		FD_ZERO(&rfd);
 		FD_SET(ttyfd, &rfd);
 		FD_SET(xfd, &rfd);
 
+		if (XPending(xw.dpy))
+			timeout = 0;  /* existing events might not set xfd */
+
+		seltv.tv_sec = timeout / 1E3;
+		seltv.tv_nsec = 1E6 * (timeout - 1E3 * seltv.tv_sec);
+		tv = timeout >= 0 ? &seltv : NULL;
+
 		if (pselect(MAX(xfd, ttyfd)+1, &rfd, NULL, NULL, tv, NULL) < 0) {
 			if (errno == EINTR)
 				continue;
 			die("select failed: %s\n", strerror(errno));
 		}
-		if (FD_ISSET(ttyfd, &rfd)) {
-			ttyread();
-			if (blinktimeout) {
-				blinkset = tattrset(ATTR_BLINK);
-				if (!blinkset)
-					MODBIT(win.mode, 0, MODE_BLINK);
-			}
-		}
+		clock_gettime(CLOCK_MONOTONIC, &now);
 
-		if (FD_ISSET(xfd, &rfd))
-			xev = actionfps;
+		if (FD_ISSET(ttyfd, &rfd))
+			ttyread();
 
-		clock_gettime(CLOCK_MONOTONIC, &now);
-		drawtimeout.tv_sec = 0;
-		drawtimeout.tv_nsec =  (1000 * 1E6)/ xfps;
-		tv = &drawtimeout;
-
-		dodraw = 0;
-		if (blinktimeout && TIMEDIFF(now, lastblink) > blinktimeout) {
-			tsetdirtattr(ATTR_BLINK);
-			win.mode ^= MODE_BLINK;
-			lastblink = now;
-			dodraw = 1;
-		}
-		deltatime = TIMEDIFF(now, last);
-		if (deltatime > 1000 / (xev ? xfps : actionfps)) {
-			dodraw = 1;
-			last = now;
+		xev = 0;
+		while (XPending(xw.dpy)) {
+			xev = 1;
+			XNextEvent(xw.dpy, &ev);
+			if (XFilterEvent(&ev, None))
+				continue;
+			if (handler[ev.type])
+				(handler[ev.type])(&ev);
 		}
 
-		if (dodraw) {
-			while (XPending(xw.dpy)) {
-				XNextEvent(xw.dpy, &ev);
-				if (XFilterEvent(&ev, None))
-					continue;
-				if (handler[ev.type])
-					(handler[ev.type])(&ev);
+		/*
+		 * To reduce flicker and tearing, when new content or event
+		 * triggers drawing, we first wait a bit to ensure we got
+		 * everything, and if nothing new arrives - we draw.
+		 * We start with trying to wait minlatency ms. If more content
+		 * arrives sooner, we retry with shorter and shorter periods,
+		 * and eventually draw even without idle after maxlatency ms.
+		 * Typically this results in low latency while interacting,
+		 * 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 (!drawing) {
+				trigger = now;
+				drawing = 1;
 			}
+			timeout = (maxlatency - TIMEDIFF(now, trigger)) \
+			          / maxlatency * minlatency;
+			if (timeout > 0)
+				continue;  /* we have time, try to find idle */
+		}
 
-			draw();
-			XFlush(xw.dpy);
-
-			if (xev && !FD_ISSET(xfd, &rfd))
-				xev--;
-			if (!FD_ISSET(ttyfd, &rfd) && !FD_ISSET(xfd, &rfd)) {
-				if (blinkset) {
-					if (TIMEDIFF(now, lastblink) \
-							> blinktimeout) {
-						drawtimeout.tv_nsec = 1000;
-					} else {
-						drawtimeout.tv_nsec = (1E6 * \
-							(blinktimeout - \
-							TIMEDIFF(now,
-								lastblink)));
-					}
-					drawtimeout.tv_sec = \
-					    drawtimeout.tv_nsec / 1E9;
-					drawtimeout.tv_nsec %= (long)1E9;
-				} else {
-					tv = NULL;
-				}
+		/* idle detected or maxlatency exhausted -> draw */
+		timeout = -1;
+		if (blinktimeout && tattrset(ATTR_BLINK)) {
+			timeout = blinktimeout - TIMEDIFF(now, lastblink);
+			if (timeout <= 0) {
+				if (-timeout > blinktimeout) /* start visible */
+					win.mode |= MODE_BLINK;
+				win.mode ^= MODE_BLINK;
+				tsetdirtattr(ATTR_BLINK);
+				lastblink = now;
+				timeout = blinktimeout;
 			}
 		}
+
+		draw();
+		XFlush(xw.dpy);
+		drawing = 0;
 	}
 }
 
@@ -2050,7 +2110,7 @@ main(int argc, char *argv[])
 {
 	xw.l = xw.t = 0;
 	xw.isfixed = False;
-	win.cursor = cursorshape;
+	xsetcursor(cursorshape);
 
 	ARGBEGIN {
 	case 'a':