Added fallback font support

config.def.h

@@ -6,6 +6,12 @@
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
 static char *font = "Liberation Mono:pixelsize=12:antialias=true:autohint=true";
+/* Spare fonts */
+static char *font2[] = {
+/*	"Inconsolata for Powerline:pixelsize=12:antialias=true:autohint=true", */
+/*	"Hack Nerd Font Mono:pixelsize=11:antialias=true:autohint=true", */
+};
+
 static int borderpx = 2;
 
 /*

config.h

@@ -5,7 +5,10 @@
  *
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
-static char *font = "Fira Code:size=10";
+static char *font = "Fira Code:size=11";
+static char *font2[] = {
+    "Noto Color Emoji:size=10"
+};
 static int borderpx = 2;
 float alpha = 0.8;
 

x.c

@@ -160,6 +160,8 @@ static void xhints(void);
 static int xloadcolor(int, const char *, Color *);
 static int xloadfont(Font *, FcPattern *);
 static void xloadfonts(char *, double);
+static int xloadsparefont(FcPattern *, int);
+static void xloadsparefonts(void);
 static void xunloadfont(Font *);
 static void xunloadfonts(void);
 static void xsetenv(void);
@@ -310,6 +312,7 @@ zoomabs(const Arg *arg)
 {
 	xunloadfonts();
 	xloadfonts(usedfont, arg->f);
+	xloadsparefonts();
 	cresize(0, 0);
 	redraw();
 	xhints();
@@ -1034,6 +1037,101 @@ xloadfonts(char *fontstr, double fontsize)
 	FcPatternDestroy(pattern);
 }
 
+int
+xloadsparefont(FcPattern *pattern, int flags)
+{
+	FcPattern *match;
+	FcResult result;
+	
+	match = FcFontMatch(NULL, pattern, &result);
+	if (!match) {
+		return 1;
+	}
+
+	if (!(frc[frclen].font = XftFontOpenPattern(xw.dpy, match))) {
+		FcPatternDestroy(match);
+		return 1;
+	}
+
+	frc[frclen].flags = flags;
+	/* Believe U+0000 glyph will present in each default font */
+	frc[frclen].unicodep = 0;
+	frclen++;
+
+	return 0;
+}
+
+void
+xloadsparefonts(void)
+{
+	FcPattern *pattern;
+	double sizeshift, fontval;
+	int fc;
+	char **fp;
+
+	if (frclen != 0)
+		die("can't embed spare fonts. cache isn't empty");
+
+	/* Calculate count of spare fonts */
+	fc = sizeof(font2) / sizeof(*font2);
+	if (fc == 0)
+		return;
+
+	/* Allocate memory for cache entries. */
+	if (frccap < 4 * fc) {
+		frccap += 4 * fc - frccap;
+		frc = xrealloc(frc, frccap * sizeof(Fontcache));
+	}
+
+	for (fp = font2; fp - font2 < fc; ++fp) {
+	
+		if (**fp == '-')
+			pattern = XftXlfdParse(*fp, False, False);
+		else
+			pattern = FcNameParse((FcChar8 *)*fp);
+	
+		if (!pattern)
+			die("can't open spare font %s\n", *fp);
+	   		
+		if (defaultfontsize > 0) {
+			sizeshift = usedfontsize - defaultfontsize;
+			if (sizeshift != 0 &&
+					FcPatternGetDouble(pattern, FC_PIXEL_SIZE, 0, &fontval) ==
+					FcResultMatch) {	
+				fontval += sizeshift;
+				FcPatternDel(pattern, FC_PIXEL_SIZE);
+				FcPatternDel(pattern, FC_SIZE);
+				FcPatternAddDouble(pattern, FC_PIXEL_SIZE, fontval);
+			}
+		}
+	
+		FcPatternAddBool(pattern, FC_SCALABLE, 1);
+	
+		FcConfigSubstitute(NULL, pattern, FcMatchPattern);
+		XftDefaultSubstitute(xw.dpy, xw.scr, pattern);
+	
+		if (xloadsparefont(pattern, FRC_NORMAL))
+			die("can't open spare font %s\n", *fp);
+	
+		FcPatternDel(pattern, FC_SLANT);
+		FcPatternAddInteger(pattern, FC_SLANT, FC_SLANT_ITALIC);
+		if (xloadsparefont(pattern, FRC_ITALIC))
+			die("can't open spare font %s\n", *fp);
+			
+		FcPatternDel(pattern, FC_WEIGHT);
+		FcPatternAddInteger(pattern, FC_WEIGHT, FC_WEIGHT_BOLD);
+		if (xloadsparefont(pattern, FRC_ITALICBOLD))
+			die("can't open spare font %s\n", *fp);
+	
+		FcPatternDel(pattern, FC_SLANT);
+		FcPatternAddInteger(pattern, FC_SLANT, FC_SLANT_ROMAN);
+		if (xloadsparefont(pattern, FRC_BOLD))
+			die("can't open spare font %s\n", *fp);
+	
+		FcPatternDestroy(pattern);
+	}
+}
+
 void
 xunloadfont(Font *f)
 {
@@ -1146,6 +1244,9 @@ xinit(int cols, int rows)
 	usedfont = (opt_font == NULL)? font : opt_font;
 	xloadfonts(usedfont, 0);
 
+	/* spare fonts */
+	xloadsparefonts();
+
 	/* colors */
 	xw.cmap = XCreateColormap(xw.dpy, parent, xw.vis, None);
 	xloadcols();

x.c.orig

@@ -19,6 +19,7 @@ char *argv0;
 #include "arg.h"
 #include "st.h"
 #include "win.h"
+#include "hb.h"
 
 /* types used in config.h */
 typedef struct {
@@ -1045,6 +1046,9 @@ 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);
@@ -1253,7 +1257,7 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 		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. */
@@ -1365,6 +1369,9 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 		numspecs++;
 	}
 
+	/* Harfbuzz transformation for ligatures. */
+	hbtransform(specs, glyphs, len, x, y);
+
 	return numspecs;
 }
 
@@ -1518,14 +1525,17 @@ 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;