patch: ligatures

Makefile

@@ -4,7 +4,7 @@
 
 include config.mk
 
-SRC = st.c x.c
+SRC = st.c x.c hb.c
 OBJ = $(SRC:.c=.o)
 
 all: st
@@ -16,7 +16,8 @@ config.h:
 	$(CC) $(STCFLAGS) -c $<
 
 st.o: config.h st.h win.h
-x.o: arg.h config.h st.h win.h
+x.o: arg.h config.h st.h win.h hb.h
+hb.o: st.h
 
 $(OBJ): config.h config.mk
 

config.mk

@@ -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 \
        `$(PKG_CONFIG) --libs fontconfig` \
-       `$(PKG_CONFIG) --libs freetype2`
+       `$(PKG_CONFIG) --libs freetype2` \
+       `$(PKG_CONFIG) --libs harfbuzz`
 
 # flags
 STCPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600
@@ -29,7 +31,8 @@ STLDFLAGS = $(LIBS) $(LDFLAGS)
 #CPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600 -D_BSD_SOURCE
 #LIBS = -L$(X11LIB) -lm -lX11 -lutil -lXft \
 #       `$(PKG_CONFIG) --libs fontconfig` \
-#       `$(PKG_CONFIG) --libs freetype2`
+#       `$(PKG_CONFIG) --libs freetype2` \
+#       `$(PKG_CONFIG) --libs harfbuzz`
 #MANPREFIX = ${PREFIX}/man
 
 # compiler and linker

st.c

@@ -2864,7 +2864,8 @@ draw(void)
 	drawregion(0, 0, term.col, term.row);
 	if (TSCREEN.off == 0)
 		xdrawcursor(cx, term.c.y, TLINE(term.c.y)[cx],
-				term.ocx, term.ocy, TLINE(term.ocy)[term.ocx]);
+			term.ocx, term.ocy, TLINE(term.ocy)[term.ocx],
+			TLINE(term.ocy), term.col);
 	term.ocx = cx;
 	term.ocy = term.c.y;
 	xfinishdraw();

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)) != ((b).mode & (~ATTR_WRAP)) || \
+				(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)

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);

x.c

@@ -20,6 +20,7 @@ char *argv0;
 #include "arg.h"
 #include "st.h"
 #include "win.h"
+#include "hb.h"
 
 /* types used in config.h */
 typedef struct {
@@ -146,8 +147,9 @@ typedef struct {
 } DC;
 
 static inline ushort sixd_to_16bit(int);
+static void xresetfontsettings(ushort mode, Font **font, int *frcflags);
 static int xmakeglyphfontspecs(XftGlyphFontSpec *, const Glyph *, int, int, int);
-static void xdrawglyphfontspecs(const XftGlyphFontSpec *, Glyph, int, int, int);
+static void xdrawglyphfontspecs(const XftGlyphFontSpec *, Glyph, int, int, int, int);
 static void xdrawglyph(Glyph, int, int);
 static void xclear(int, int, int, int);
 static int xgeommasktogravity(int);
@@ -777,7 +779,7 @@ xresize(int col, int row)
 	xclear(0, 0, win.w, win.h);
 
 	/* resize to new width */
-	xw.specbuf = xrealloc(xw.specbuf, col * sizeof(GlyphFontSpec));
+	xw.specbuf = xrealloc(xw.specbuf, col * sizeof(GlyphFontSpec) * 4);
 }
 
 ushort
@@ -1082,6 +1084,9 @@ 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);
@@ -1208,7 +1213,7 @@ xinit(int cols, int rows)
 	XFillRectangle(xw.dpy, xw.buf, dc.gc, 0, 0, win.w, win.h);
 
 	/* font spec buffer */
-	xw.specbuf = xmalloc(cols * sizeof(GlyphFontSpec));
+	xw.specbuf = xmalloc(cols * sizeof(GlyphFontSpec) * 4);
 
 	/* Xft rendering context */
 	xw.draw = XftDrawCreate(xw.dpy, xw.buf, xw.vis, xw.cmap);
@@ -1262,142 +1267,153 @@ xinit(int cols, int rows)
 		xsel.xtarget = XA_STRING;
 }
 
+void
+xresetfontsettings(ushort mode, Font **font, int *frcflags)
+{
+	*font = &dc.font;
+	if ((mode & ATTR_ITALIC) && (mode & ATTR_BOLD)) {
+		*font = &dc.ibfont;
+		*frcflags = FRC_ITALICBOLD;
+	} else if (mode & ATTR_ITALIC) {
+		*font = &dc.ifont;
+		*frcflags = FRC_ITALIC;
+	} else if (mode & ATTR_BOLD) {
+		*font = &dc.bfont;
+		*frcflags = FRC_BOLD;
+	}
+}
+
 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;
-	ushort mode, prevmode = USHRT_MAX;
+	ushort mode = glyphs[0].mode & ~ATTR_WRAP;
 	Font *font = &dc.font;
 	int frcflags = FRC_NORMAL;
-	float runewidth = win.cw;
+	float runewidth = win.cw * ((glyphs[0].mode & ATTR_WIDE) ? 2.0f : 1.0f);
 	Rune rune;
 	FT_UInt glyphidx;
 	FcResult fcres;
 	FcPattern *fcpattern, *fontpattern;
 	FcFontSet *fcsets[] = { NULL };
 	FcCharSet *fccharset;
-	int i, f, numspecs = 0;
+	int f, code_idx, numspecs = 0;
+	float cluster_xp = xp, cluster_yp = yp;
+	HbTransformData shaped = { 0 };
 
-	for (i = 0, xp = winx, yp = winy + font->ascent; i < len; ++i) {
+	/* Initial values. */
-		/* Fetch rune and mode for current glyph. */
+	xresetfontsettings(mode, &font, &frcflags);
-		rune = glyphs[i].u;
-		mode = glyphs[i].mode;
 
-		/* Skip dummy wide-character spacing. */
+	/* Shape the segment. */
-		if (mode == ATTR_WDUMMY)
+	hbtransform(&shaped, font->match, glyphs, 0, len);
+	xp = winx; yp = winy + font->ascent;
+	cluster_xp = xp; cluster_yp = yp;
+
+	for (code_idx = 0; code_idx < shaped.count; code_idx++) {
+		int idx = shaped.glyphs[code_idx].cluster;
+
+		if (glyphs[idx].mode & ATTR_WDUMMY)
 			continue;
 
-		/* Determine font for glyph if different from previous glyph. */
+		/* Advance the drawing cursor if we've moved to a new cluster */
-		if (prevmode != mode) {
+		if (code_idx > 0 && (idx != shaped.glyphs[code_idx - 1].cluster)) {
-			prevmode = mode;
+			xp += runewidth * (idx - shaped.glyphs[code_idx - 1].cluster);
-			font = &dc.font;
+			cluster_xp = xp;
-			frcflags = FRC_NORMAL;
+			cluster_yp = yp;
-			runewidth = win.cw * ((mode & ATTR_WIDE) ? 2.0f : 1.0f);
-			if ((mode & ATTR_ITALIC) && (mode & ATTR_BOLD)) {
-				font = &dc.ibfont;
-				frcflags = FRC_ITALICBOLD;
-			} else if (mode & ATTR_ITALIC) {
-				font = &dc.ifont;
-				frcflags = FRC_ITALIC;
-			} else if (mode & ATTR_BOLD) {
-				font = &dc.bfont;
-				frcflags = FRC_BOLD;
-			}
-			yp = winy + font->ascent;
 		}
 
-		/* Lookup character index with default font. */
+		if (shaped.glyphs[code_idx].codepoint != 0) {
-		glyphidx = XftCharIndex(xw.dpy, font->match, rune);
+			/* If symbol is found, put it into the specs. */
-		if (glyphidx) {
 			specs[numspecs].font = font->match;
+			specs[numspecs].glyph = shaped.glyphs[code_idx].codepoint;
+			specs[numspecs].x = cluster_xp + (short)(shaped.positions[code_idx].x_offset / 64.);
+			specs[numspecs].y = cluster_yp - (short)(shaped.positions[code_idx].y_offset / 64.);
+			cluster_xp += shaped.positions[code_idx].x_advance / 64.;
+			cluster_yp += shaped.positions[code_idx].y_advance / 64.;
+			numspecs++;
+		} else {
+			/* If it's not found, try to fetch it through the font cache. */
+			rune = glyphs[idx].u;
+			for (f = 0; f < frclen; f++) {
+				glyphidx = XftCharIndex(xw.dpy, frc[f].font, rune);
+				/* Everything correct. */
+				if (glyphidx && frc[f].flags == frcflags)
+					break;
+				/* We got a default font for a not found glyph. */
+				if (!glyphidx && frc[f].flags == frcflags
+						&& frc[f].unicodep == rune) {
+					break;
+				}
+			}
+
+			/* Nothing was found. Use fontconfig to find matching font. */
+			if (f >= frclen) {
+				if (!font->set)
+					font->set = FcFontSort(0, font->pattern,
+							       1, 0, &fcres);
+				fcsets[0] = font->set;
+
+				/*
+				 * Nothing was found in the cache. Now use
+				 * some dozen of Fontconfig calls to get the
+				 * font for one single character.
+				 *
+				 * Xft and fontconfig are design failures.
+				 */
+				fcpattern = FcPatternDuplicate(font->pattern);
+				fccharset = FcCharSetCreate();
+
+				FcCharSetAddChar(fccharset, rune);
+				FcPatternAddCharSet(fcpattern, FC_CHARSET,
+						fccharset);
+				FcPatternAddBool(fcpattern, FC_SCALABLE, 1);
+
+				FcConfigSubstitute(0, fcpattern,
+						FcMatchPattern);
+				FcDefaultSubstitute(fcpattern);
+
+				fontpattern = FcFontSetMatch(0, fcsets, 1,
+						fcpattern, &fcres);
+
+				/* Allocate memory for the new cache entry. */
+				if (frclen >= frccap) {
+					frccap += 16;
+					frc = xrealloc(frc, frccap * sizeof(Fontcache));
+				}
+
+				frc[frclen].font = XftFontOpenPattern(xw.dpy,
+						fontpattern);
+				if (!frc[frclen].font)
+					die("XftFontOpenPattern failed seeking fallback font: %s\n",
+						strerror(errno));
+				frc[frclen].flags = frcflags;
+				frc[frclen].unicodep = rune;
+
+				glyphidx = XftCharIndex(xw.dpy, frc[frclen].font, rune);
+
+				f = frclen;
+				frclen++;
+
+				FcPatternDestroy(fcpattern);
+				FcCharSetDestroy(fccharset);
+			}
+
+			specs[numspecs].font = frc[f].font;
 			specs[numspecs].glyph = glyphidx;
 			specs[numspecs].x = (short)xp;
 			specs[numspecs].y = (short)yp;
-			xp += runewidth;
 			numspecs++;
-			continue;
 		}
-
-		/* Fallback on font cache, search the font cache for match. */
-		for (f = 0; f < frclen; f++) {
-			glyphidx = XftCharIndex(xw.dpy, frc[f].font, rune);
-			/* Everything correct. */
-			if (glyphidx && frc[f].flags == frcflags)
-				break;
-			/* We got a default font for a not found glyph. */
-			if (!glyphidx && frc[f].flags == frcflags
-					&& frc[f].unicodep == rune) {
-				break;
-			}
-		}
-
-		/* Nothing was found. Use fontconfig to find matching font. */
-		if (f >= frclen) {
-			if (!font->set)
-				font->set = FcFontSort(0, font->pattern,
-				                       1, 0, &fcres);
-			fcsets[0] = font->set;
-
-			/*
-			 * Nothing was found in the cache. Now use
-			 * some dozen of Fontconfig calls to get the
-			 * font for one single character.
-			 *
-			 * Xft and fontconfig are design failures.
-			 */
-			fcpattern = FcPatternDuplicate(font->pattern);
-			fccharset = FcCharSetCreate();
-
-			FcCharSetAddChar(fccharset, rune);
-			FcPatternAddCharSet(fcpattern, FC_CHARSET,
-					fccharset);
-			FcPatternAddBool(fcpattern, FC_SCALABLE, 1);
-
-			FcConfigSubstitute(0, fcpattern,
-					FcMatchPattern);
-			FcDefaultSubstitute(fcpattern);
-
-			fontpattern = FcFontSetMatch(0, fcsets, 1,
-					fcpattern, &fcres);
-
-			/* Allocate memory for the new cache entry. */
-			if (frclen >= frccap) {
-				frccap += 16;
-				frc = xrealloc(frc, frccap * sizeof(Fontcache));
-			}
-
-			frc[frclen].font = XftFontOpenPattern(xw.dpy,
-					fontpattern);
-			if (!frc[frclen].font)
-				die("XftFontOpenPattern failed seeking fallback font: %s\n",
-					strerror(errno));
-			frc[frclen].flags = frcflags;
-			frc[frclen].unicodep = rune;
-
-			glyphidx = XftCharIndex(xw.dpy, frc[frclen].font, rune);
-
-			f = frclen;
-			frclen++;
-
-			FcPatternDestroy(fcpattern);
-			FcCharSetDestroy(fccharset);
-		}
-
-		specs[numspecs].font = frc[f].font;
-		specs[numspecs].glyph = glyphidx;
-		specs[numspecs].x = (short)xp;
-		specs[numspecs].y = (short)yp;
-		xp += runewidth;
-		numspecs++;
 	}
 
+	/* Cleanup and get ready for next segment. */
+	hbcleanup(&shaped);
 	return numspecs;
 }
 
 void
-xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, int y)
+xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, int y, int charlen)
 {
-	int charlen = len * ((base.mode & ATTR_WIDE) ? 2 : 1);
 	int winx = borderpx + x * win.cw, winy = borderpx + y * win.ch,
 	    width = charlen * win.cw;
 	Color *fg, *bg, *temp, revfg, revbg, truefg, truebg;
@@ -1529,21 +1545,24 @@ void
 xdrawglyph(Glyph g, int x, int y)
 {
 	int numspecs;
-	XftGlyphFontSpec spec;
+	XftGlyphFontSpec *specs = xw.specbuf;
 
-	numspecs = xmakeglyphfontspecs(&spec, &g, 1, x, y);
+	numspecs = xmakeglyphfontspecs(specs, &g, 1, x, y);
-	xdrawglyphfontspecs(&spec, g, numspecs, x, y);
+	xdrawglyphfontspecs(specs, g, numspecs, x, y, (g.mode & ATTR_WIDE) ? 2 : 1);
 }
 
 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;
@@ -1677,18 +1696,16 @@ xdrawline(Line line, int x1, int y1, int x2)
 	Glyph base, new;
 	XftGlyphFontSpec *specs = xw.specbuf;
 
-	numspecs = xmakeglyphfontspecs(specs, &line[x1], x2 - x1, x1, y1);
 	i = ox = 0;
-	for (x = x1; x < x2 && i < numspecs; x++) {
+	for (x = x1; x < x2; x++) {
 		new = line[x];
 		if (new.mode == ATTR_WDUMMY)
 			continue;
 		if (selected(x, y1))
 			new.mode ^= ATTR_REVERSE;
-		if (i > 0 && ATTRCMP(base, new)) {
+		if ((i > 0) && ATTRCMP(base, new)) {
-			xdrawglyphfontspecs(specs, base, i, ox, y1);
+			numspecs = xmakeglyphfontspecs(specs, &line[ox], x - ox, ox, y1);
-			specs += i;
+			xdrawglyphfontspecs(specs, base, numspecs, ox, y1, x - ox);
-			numspecs -= i;
 			i = 0;
 		}
 		if (i == 0) {
@@ -1697,8 +1714,10 @@ xdrawline(Line line, int x1, int y1, int x2)
 		}
 		i++;
 	}
-	if (i > 0)
+	if (i > 0) {
-		xdrawglyphfontspecs(specs, base, i, ox, y1);
+		numspecs = xmakeglyphfontspecs(specs, &line[ox], x2 - ox, ox, y1);
+		xdrawglyphfontspecs(specs, base, numspecs, ox, y1, x2 - ox);
+	}
 }
 
 void