Ignore color fonts when using Xft

* src/font.c (syms_of_font): New configuration variable
xft-ignore-color-fonts, default t.
* src/ftfont.c (ftfont_spec_pattern): Tell fontconfig to ignore
color fonts if xft-ignore-color-fonts is t.  (Bug#30874, Bug#30045)
* etc/NEWS: Document xft-ignore-color-fonts.

diff --git a/etc/NEWS b/etc/NEWS
index a510c03956acd122c5fe8c594b8192acf72a896d..7dc014707b3547f97269677817768a700a568d7d 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -77,6 +77,12 @@ work right without some adjustment:
 \f
 * Changes in Emacs 27.1
 
+---
+** New variable 'xft-ignore-color-fonts'.
+Default t means don't try to load color fonts when using Xft, as they
+often cause crashes.  Set it to nil if you really need those fonts.
+(Bug#30874)
+
 ---
 ** The new option 'tooltip-resize-echo-area' avoids truncating tooltip text
 on GUI frames when tooltips are displayed in the echo area.  Instead,

diff --git a/src/font.c b/src/font.c
index a6d3f5d479867493020ca8d70f4863c2ff15a371..ef3f92b59499f84ff713a7bded8db7f3ade35a0a 100644 (file)
--- a/src/font.c
+++ b/src/font.c
@@ -5473,6 +5473,13 @@ Disabling compaction of font caches might enlarge the Emacs memory
 footprint in sessions that use lots of different fonts.  */);
   inhibit_compacting_font_caches = 0;
 
+  DEFVAR_BOOL ("xft-ignore-color-fonts",
+              Vxft_ignore_color_fonts,
+              doc: /*
+Non-nil means don't query fontconfig for color fonts, since they often
+cause Xft crashes.  Only has an effect in Xft builds.  */);
+  Vxft_ignore_color_fonts = 1;
+
 #ifdef HAVE_WINDOW_SYSTEM
 #ifdef HAVE_FREETYPE
   syms_of_ftfont ();

diff --git a/src/ftfont.c b/src/ftfont.c
index c2e093e633d533cf7583787242c3134e5c95d32f..24a92dd52e8a987b307b4c148bdc30cf9e5068ae 100644 (file)
--- a/src/ftfont.c
+++ b/src/ftfont.c
@@ -764,6 +764,13 @@ ftfont_spec_pattern (Lisp_Object spec, char *otlayout, struct OpenTypeSpec **ots
   if (scalable >= 0
       && ! FcPatternAddBool (pattern, FC_SCALABLE, scalable ? FcTrue : FcFalse))
     goto err;
+#ifdef HAVE_XFT
+  /* We really don't like color fonts, they cause Xft crashes.  See
+     Bug#30874.  */
+  if (Vxft_ignore_color_fonts
+      && ! FcPatternAddBool(pattern, FC_COLOR, FcFalse))
+    goto err;
+#endif
 
   goto finish;