From 762a8843c38736c6b9ff3cfe93eb86b2f24bf9ea Mon Sep 17 00:00:00 2001
From: Sanchayan Maity <maitysanchayan@gmail.com>
Date: Tue, 17 Nov 2020 12:20:16 +0530
Subject: [PATCH] Apply the font2 patch

See https://st.suckless.org/patches/font2/.

This patch allows to add spare font besides default. Some glyphs can be not
present in default font. For this glyphs st uses font-config and try to find
them in font cache first. This patch append fonts defined in font2 variable
to the beginning of font cache. So they will be used first for glyphs that
absent in default font.

This is required to improve the rendering of special unicode characters
we currently use in neovim statusline.
---
 config.h |   4 +++
 x.c      | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/config.h b/config.h
index 2628d89..1925fdf 100644
--- a/config.h
+++ b/config.h
@@ -6,6 +6,10 @@
  * font: see http://freedesktop.org/software/fontconfig/fontconfig-user.html
  */
 static char *font = "JetBrains Mono Medium:style=Medium Italic,Italic:pixelsize=14:antialias=true:autohint=true";
+/* Spare fonts */
+static char *font2[] = {
+	"TerminessTTF Nerd Font:pixelsize=14:antialias=true:autohint=true",
+};
 static int borderpx = 0;
 
 /*
diff --git a/x.c b/x.c
index 69435f8..c110c00 100644
--- a/x.c
+++ b/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();
@@ -1036,6 +1039,101 @@ 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)
 {
@@ -1148,6 +1246,9 @@ 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();