Patch that introduces a hack to solve nerdfont icon cutoff in dwm

dwm-xft_fix-6.2.diff

diff --git a/config.mk b/config.mk
index 7084c33..1b29d76 100644
--- a/config.mk
+++ b/config.mk
@@ -15,7 +15,7 @@ XINERAMALIBS  = -lXinerama
 XINERAMAFLAGS = -DXINERAMA
 
 # freetype
-FREETYPELIBS = -lfontconfig -lXft
+FREETYPELIBS = -lfontconfig -lXft `pkg-config --libs freetype2`
 FREETYPEINC = /usr/include/freetype2
 # OpenBSD (uncomment)
 #FREETYPEINC = ${X11INC}/freetype2
diff --git a/drw.c b/drw.c
index 4cdbcbe..e061598 100644
--- a/drw.c
+++ b/drw.c
@@ -10,6 +10,7 @@
 
 #define UTF_INVALID 0xFFFD
 #define UTF_SIZ     4
+#define NUM_LOCAL   1024
 
 static const unsigned char utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
 static const unsigned char utfmask[UTF_SIZ + 1] = {0xC0, 0x80, 0xE0, 0xF0, 0xF8};
@@ -140,11 +141,11 @@ xfont_create(Drw *drw, const char *fontname, FcPattern *fontpattern)
 	 * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=916349
 	 * and lots more all over the internet.
 	 */
-	FcBool iscol;
-	if(FcPatternGetBool(xfont->pattern, FC_COLOR, 0, &iscol) == FcResultMatch && iscol) {
-		XftFontClose(drw->dpy, xfont);
-		return NULL;
-	}
+	/* FcBool iscol; */
+	/* if(FcPatternGetBool(xfont->pattern, FC_COLOR, 0, &iscol) == FcResultMatch && iscol) { */
+		/* XftFontClose(drw->dpy, xfont); */
+		/* return NULL; */
+	/* } */
 
 	font = ecalloc(1, sizeof(Fnt));
 	font->xfont = xfont;
@@ -265,6 +266,7 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 	FcPattern *match;
 	XftResult result;
 	int charexists = 0;
+	GlyphWidths gw;
 
 	if (!drw || (render && !drw->scheme) || !text || !drw->fonts)
 		return 0;
@@ -308,10 +310,15 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 		}
 
 		if (utf8strlen) {
-			drw_font_getexts(usedfont, utf8str, utf8strlen, &ew, NULL);
+			gw = drw_font_getexts(usedfont, utf8str, utf8strlen, &ew, NULL);
 			/* shorten text if necessary */
-			for (len = MIN(utf8strlen, sizeof(buf) - 1); len && ew > w; len--)
-				drw_font_getexts(usedfont, utf8str, len, &ew, NULL);
+			for (len = MIN(utf8strlen, sizeof(buf) - 1); len && ew > w; len--) {
+				if (gw.nglyphs) {
+					gw.nglyphs = 0;
+					free(gw.glyphwidths);
+				}
+				gw = drw_font_getexts(usedfont, utf8str, len, &ew, NULL);
+			}
 
 			if (len) {
 				memcpy(buf, utf8str, len);
@@ -322,12 +329,17 @@ drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned int lp
 
 				if (render) {
 					ty = y + (h - usedfont->h) / 2 + usedfont->xfont->ascent;
-					XftDrawStringUtf8(d, &drw->scheme[invert ? ColBg : ColFg],
-					                  usedfont->xfont, x, ty, (XftChar8 *)buf, len);
+					XftPatchedDrawStringUtf8(drw->dpy, d, &drw->scheme[invert ? ColBg : ColFg], usedfont->xfont, x, ty, (XftChar8 *)buf, len, gw);
+					/* XftDrawStringUtf8(d, &drw->scheme[invert ? ColBg : ColFg], usedfont->xfont, x, ty, (XftChar8 *)buf, len); */
 				}
 				x += ew;
 				w -= ew;
 			}
+
+			if (gw.nglyphs) {
+				gw.nglyphs = 0;
+				free(gw.glyphwidths);
+			}
 		}
 
 		if (!*text) {
@@ -397,19 +409,28 @@ drw_fontset_getwidth(Drw *drw, const char *text)
 	return drw_text(drw, 0, 0, 0, 0, 0, text, 0);
 }
 
-void
+GlyphWidths
 drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned int *w, unsigned int *h)
 {
 	XGlyphInfo ext;
+	GlyphWidths res;
+
+	res.nglyphs = 0;
+	res.glyphwidths = NULL;
 
 	if (!font || !text)
-		return;
+		return res;
 
-	XftTextExtentsUtf8(font->dpy, font->xfont, (XftChar8 *)text, len, &ext);
 	if (w)
+	{
+		res = XftPatchedTextExtentsUtf8(font->dpy, font->xfont, (XftChar8 *)text, len, &ext);
 		*w = ext.xOff;
-	if (h)
+	} else if (h) {
+		XftTextExtentsUtf8(font->dpy, font->xfont, (XftChar8 *)text, len, &ext);
 		*h = font->h;
+	}
+
+	return res;
 }
 
 Cur *
@@ -434,3 +455,122 @@ drw_cur_free(Drw *drw, Cur *cursor)
 	XFreeCursor(drw->dpy, cursor->cursor);
 	free(cursor);
 }
+
+void
+XftPatchedDrawStringUtf8 (Display	*dpy, XftDraw *draw, XftColor *color, XftFont *pub, int x, int	y, FcChar8 *string, int len, GlyphWidths gw)
+{
+    FT_UInt	*glyphs, glyphs_local[NUM_LOCAL];
+    FcChar32 ucs4;
+    int	l, i = 0, size = NUM_LOCAL, deltax = 0, len_orig = len;
+		FT_UInt *glyph;
+		FcChar8 *string_orig = string;
+
+    glyphs = glyphs_local;
+    while (len && (l = FcUtf8ToUcs4 (string, &ucs4, len)) > 0) {
+			if (i == size)
+				break;		/* This hack doesn't support strings longer than NUM_LOCAL */
+			glyphs[i++] = XftCharIndex (dpy, pub, ucs4);
+			string += l;
+			len -= l;
+		}
+
+		if (gw.nglyphs && (gw.nglyphs == i))
+		{
+			/* Patched drawing */
+			for (l = 0; l < i; l++) {
+				glyph = &glyphs[l];
+				XftDrawGlyphs (draw, color, pub, x + deltax, y, glyph, 1);
+				deltax += gw.glyphwidths[l];
+			}
+		} else {
+			/* Default drawing */
+			XftDrawStringUtf8(draw, color, pub, x, y, string_orig, len_orig);
+		}
+}
+
+GlyphWidths
+XftPatchedGlyphExtents (Display	*dpy, XftFont	*pub, FT_UInt *glyphs, int nglyphs, XGlyphInfo *extents)
+{
+  int	advancex, width, glyphwidth, bitmap, n = nglyphs, x = 0, i = 0;
+	int *glyphwidths;
+  FT_UInt	*g = glyphs;
+  FT_UInt	glyph;
+  FT_Face	face;
+	FT_Error error;
+	GlyphWidths res;
+
+	/* Calculate the length "correctly" */
+	/* This is a gross oversimplification of what Xft does and may not always work */
+  face = XftLockFace (pub);
+	glyphwidths = (int *)calloc(nglyphs, sizeof(int));
+	while (n--) {
+		glyph = *g++;
+		bitmap = 0;
+		if ((error = FT_Load_Glyph(face, glyph, FT_LOAD_RENDER | FT_LOAD_FORCE_AUTOHINT | FT_LOAD_NO_BITMAP))) {
+	    FT_Load_Glyph(face, glyph, FT_LOAD_RENDER | FT_LOAD_FORCE_AUTOHINT | FT_LOAD_BITMAP_METRICS_ONLY);
+		  bitmap = 1;
+		}
+
+		advancex = face->glyph->advance.x >> 6;
+		if (bitmap)
+			glyphwidth = advancex;					/* Bitmaps (emoji) have unscaled width */
+		else {
+      width = face->glyph->metrics.width >> 6;
+			glyphwidth = (advancex > width ? advancex : width);
+		}
+
+		x += glyphwidth;
+		*(glyphwidths + i) = glyphwidth;
+		i++;
+	  fprintf(stderr, "Glyph = %u, width = %d, acv = %d\n", (unsigned int)glyph, glyphwidth, advancex);
+	}
+  XftUnlockFace (pub);
+
+	/* Call original glyph extents function , as xft does more than get the extents */
+	XftGlyphExtents(dpy, pub, glyphs, nglyphs, extents)	;
+
+	/* Check if our x is longer than the xOff calculated by the unpatched function */
+	extents->xOff = extents->xOff < (short)x ? (short)x : extents->xOff;
+
+	res.glyphwidths = glyphwidths;
+	res.nglyphs = nglyphs;
+	return res;
+}
+
+GlyphWidths
+XftPatchedTextExtentsUtf8 (Display *dpy, XftFont *pub, FcChar8 *string, int len, XGlyphInfo	*extents)
+{
+	FT_UInt	*glyphs, *glyphs_new, glyphs_local[NUM_LOCAL];
+  FcChar32 ucs4;
+  int l, size, i = 0;
+	GlyphWidths res;
+
+  glyphs = glyphs_local;
+  size = NUM_LOCAL;
+	res.nglyphs = 0;
+	res.glyphwidths = NULL;
+  while (len && (l = FcUtf8ToUcs4 (string, &ucs4, len)) > 0) {
+		if (i == size) {
+			glyphs_new = malloc ((size_t)size * 2 * sizeof (FT_UInt));
+	    if (!glyphs_new) {
+				if (glyphs != glyphs_local)
+					free (glyphs);
+				memset (extents, '\0', sizeof (XGlyphInfo));
+				return res;
+	    }
+	    memcpy (glyphs_new, glyphs, (size_t)size * sizeof (FT_UInt));
+	    size *= 2;
+	    if (glyphs != glyphs_local)
+				free (glyphs);
+	    glyphs = glyphs_new;
+		}
+		glyphs[i++] = XftCharIndex (dpy, pub, ucs4);
+		string += l;
+		len -= l;
+  }
+  res = XftPatchedGlyphExtents (dpy, pub, glyphs, i, extents);
+  if (glyphs != glyphs_local)
+		free (glyphs);
+
+	return res;
+}
diff --git a/drw.h b/drw.h
index 4bcd5ad..0b2d009 100644
--- a/drw.h
+++ b/drw.h
@@ -1,5 +1,10 @@
 /* See LICENSE file for copyright and license details. */
 
+typedef struct {
+	int *glyphwidths;
+	int nglyphs;
+} GlyphWidths;
+
 typedef struct {
 	Cursor cursor;
 } Cur;
@@ -35,7 +40,7 @@ void drw_free(Drw *drw);
 Fnt *drw_fontset_create(Drw* drw, const char *fonts[], size_t fontcount);
 void drw_fontset_free(Fnt* set);
 unsigned int drw_fontset_getwidth(Drw *drw, const char *text);
-void drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned int *w, unsigned int *h);
+GlyphWidths drw_font_getexts(Fnt *font, const char *text, unsigned int len, unsigned int *w, unsigned int *h);
 
 /* Colorscheme abstraction */
 void drw_clr_create(Drw *drw, Clr *dest, const char *clrname);
@@ -55,3 +60,8 @@ int drw_text(Drw *drw, int x, int y, unsigned int w, unsigned int h, unsigned in
 
 /* Map functions */
 void drw_map(Drw *drw, Window win, int x, int y, unsigned int w, unsigned int h);
+
+/* Patched drawing functions */
+void XftPatchedDrawStringUtf8 (Display	*dpy, XftDraw *draw, XftColor *color, XftFont *pub, int x, int	y, FcChar8 *string, int len, GlyphWidths gw);
+GlyphWidths XftPatchedGlyphExtents (Display	*dpy, XftFont	*pub, FT_UInt *glyphs, int nglyphs, XGlyphInfo *extents);
+GlyphWidths XftPatchedTextExtentsUtf8 (Display *dpy, XftFont *pub, FcChar8 *string, int len, XGlyphInfo	*extents);