* xfaces.c (Qignore_defface): New variable.

	(syms_of_xfaces): Provide `:ignore-defface'.
	(IGNORE_DEFFACE_P): New macro.
	(check_lface_attrs): Qignore_defface is a possible value.
	(lface_fully_specified_p): Likewise.
	(Finternal_set_lisp_face_attribute): Likewise.
	(merge_face_vectors): The merged face is `unspecified' if the
	mergee specifies `:ignore-defface'.

2 files changed, 53 insertions, 17 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 900db33db3d..dcdc481f37b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,14 @@
+2005-11-17  Chong Yidong  <cyd@stupidchicken.com>
+
+        * xfaces.c (Qignore_defface): New variable.
+        (syms_of_xfaces): Provide `:ignore-defface'.
+        (IGNORE_DEFFACE_P): New macro.
+        (check_lface_attrs): Qignore_defface is a possible value.
+        (lface_fully_specified_p): Likewise.
+        (Finternal_set_lisp_face_attribute): Likewise.
+        (merge_face_vectors): The merged face is `unspecified' if the
+        mergee specifies `:ignore-defface'.
+
 2005-11-16  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * lread.c (readevalloop): Add missing GCPROs.
diff --git a/src/xfaces.c b/src/xfaces.c
index f13fdf74909..aafa9e5e378 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -274,6 +274,10 @@ Boston, MA 02110-1301, USA.  */
 
 #define UNSPECIFIEDP(ATTR) EQ ((ATTR), Qunspecified)
 
+/* Non-zero if face attribute ATTR is `ignore-defface'.  */
+
+#define IGNORE_DEFFACE_P(ATTR) EQ ((ATTR), Qignore_defface)
+
 /* Value is the number of elements of VECTOR.  */
 
 #define DIM(VECTOR) (sizeof (VECTOR) / sizeof *(VECTOR))
@@ -312,6 +316,7 @@ Lisp_Object Qultra_expanded;
 Lisp_Object Qreleased_button, Qpressed_button;
 Lisp_Object QCstyle, QCcolor, QCline_width;
 Lisp_Object Qunspecified;
+Lisp_Object Qignore_defface;
 
 char unspecified_fg[] = "unspecified-fg", unspecified_bg[] = "unspecified-bg";
 
@@ -3104,48 +3109,64 @@ check_lface_attrs (attrs)
      Lisp_Object *attrs;
 {
   xassert (UNSPECIFIEDP (attrs[LFACE_FAMILY_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_FAMILY_INDEX])
            || STRINGP (attrs[LFACE_FAMILY_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_SWIDTH_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_SWIDTH_INDEX])
            || SYMBOLP (attrs[LFACE_SWIDTH_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_AVGWIDTH_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_AVGWIDTH_INDEX])
            || INTEGERP (attrs[LFACE_AVGWIDTH_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_HEIGHT_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_HEIGHT_INDEX])
            || INTEGERP (attrs[LFACE_HEIGHT_INDEX])
            || FLOATP (attrs[LFACE_HEIGHT_INDEX])
            || FUNCTIONP (attrs[LFACE_HEIGHT_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_WEIGHT_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_WEIGHT_INDEX])
            || SYMBOLP (attrs[LFACE_WEIGHT_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_SLANT_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_SLANT_INDEX])
            || SYMBOLP (attrs[LFACE_SLANT_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_UNDERLINE_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_UNDERLINE_INDEX])
            || SYMBOLP (attrs[LFACE_UNDERLINE_INDEX])
            || STRINGP (attrs[LFACE_UNDERLINE_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_OVERLINE_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_OVERLINE_INDEX])
            || SYMBOLP (attrs[LFACE_OVERLINE_INDEX])
            || STRINGP (attrs[LFACE_OVERLINE_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_STRIKE_THROUGH_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_STRIKE_THROUGH_INDEX])
            || SYMBOLP (attrs[LFACE_STRIKE_THROUGH_INDEX])
            || STRINGP (attrs[LFACE_STRIKE_THROUGH_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_BOX_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_BOX_INDEX])
            || SYMBOLP (attrs[LFACE_BOX_INDEX])
            || STRINGP (attrs[LFACE_BOX_INDEX])
            || INTEGERP (attrs[LFACE_BOX_INDEX])
            || CONSP (attrs[LFACE_BOX_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_INVERSE_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_INVERSE_INDEX])
            || SYMBOLP (attrs[LFACE_INVERSE_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_FOREGROUND_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_FOREGROUND_INDEX])
            || STRINGP (attrs[LFACE_FOREGROUND_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_BACKGROUND_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_BACKGROUND_INDEX])
            || STRINGP (attrs[LFACE_BACKGROUND_INDEX]));
   xassert (UNSPECIFIEDP (attrs[LFACE_INHERIT_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_INHERIT_INDEX])
            || NILP (attrs[LFACE_INHERIT_INDEX])
            || SYMBOLP (attrs[LFACE_INHERIT_INDEX])
            || CONSP (attrs[LFACE_INHERIT_INDEX]));
 #ifdef HAVE_WINDOW_SYSTEM
   xassert (UNSPECIFIEDP (attrs[LFACE_STIPPLE_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_STIPPLE_INDEX])
            || SYMBOLP (attrs[LFACE_STIPPLE_INDEX])
            || !NILP (Fbitmap_spec_p (attrs[LFACE_STIPPLE_INDEX])));
   xassert (UNSPECIFIEDP (attrs[LFACE_FONT_INDEX])
+           || IGNORE_DEFFACE_P (attrs[LFACE_FONT_INDEX])
            || NILP (attrs[LFACE_FONT_INDEX])
            || STRINGP (attrs[LFACE_FONT_INDEX]));
 #endif
@@ -3340,7 +3361,7 @@ lface_fully_specified_p (attrs)
   for (i = 1; i < LFACE_VECTOR_SIZE; ++i)
     if (i != LFACE_FONT_INDEX && i != LFACE_INHERIT_INDEX
         && i != LFACE_AVGWIDTH_INDEX)
-      if (UNSPECIFIEDP (attrs[i])
+      if ((UNSPECIFIEDP (attrs[i]) || IGNORE_DEFFACE_P (attrs[i]))
 #ifdef MAC_OS
         /* MAC_TODO: No stipple support on Mac OS yet, this index is
            always unspecified.  */
@@ -3555,6 +3576,8 @@ merge_face_vectors (f, from, to, named_merge_points)
       {
         if (i == LFACE_HEIGHT_INDEX && !INTEGERP (from[i]))
           to[i] = merge_face_heights (from[i], to[i], to[i]);
+        else if (IGNORE_DEFFACE_P (from[i]))
+          to[i] = Qunspecified;
         else
           to[i] = from[i];
       }
@@ -4047,7 +4070,7 @@ FRAME 0 means change the face on all frames, and change the default
 
   if (EQ (attr, QCfamily))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           CHECK_STRING (value);
           if (SCHARS (value) == 0)
@@ -4059,7 +4082,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCheight))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           Lisp_Object test;
 
@@ -4080,7 +4103,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCweight))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           CHECK_SYMBOL (value);
           if (face_numeric_weight (value) < 0)
@@ -4092,7 +4115,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCslant))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           CHECK_SYMBOL (value);
           if (face_numeric_slant (value) < 0)
@@ -4104,7 +4127,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCunderline))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         if ((SYMBOLP (value)
              && !EQ (value, Qt)
              && !EQ (value, Qnil))
@@ -4118,7 +4141,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCoverline))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         if ((SYMBOLP (value)
              && !EQ (value, Qt)
              && !EQ (value, Qnil))
@@ -4132,7 +4155,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCstrike_through))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         if ((SYMBOLP (value)
              && !EQ (value, Qt)
              && !EQ (value, Qnil))
@@ -4153,7 +4176,7 @@ FRAME 0 means change the face on all frames, and change the default
       if (EQ (value, Qt))
         value = make_number (1);
 
-      if (UNSPECIFIEDP (value))
+      if (UNSPECIFIEDP (value) || IGNORE_DEFFACE_P (value))
         valid_p = 1;
       else if (NILP (value))
         valid_p = 1;
@@ -4210,7 +4233,7 @@ FRAME 0 means change the face on all frames, and change the default
   else if (EQ (attr, QCinverse_video)
            || EQ (attr, QCreverse_video))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           CHECK_SYMBOL (value);
           if (!EQ (value, Qt) && !NILP (value))
@@ -4221,7 +4244,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCforeground))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           /* Don't check for valid color names here because it depends
              on the frame (display) whether the color will be valid
@@ -4235,7 +4258,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCbackground))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           /* Don't check for valid color names here because it depends
              on the frame (display) whether the color will be valid
@@ -4250,7 +4273,7 @@ FRAME 0 means change the face on all frames, and change the default
   else if (EQ (attr, QCstipple))
     {
 #ifdef HAVE_X_WINDOWS
-      if (!UNSPECIFIEDP (value)
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value)
           && !NILP (value)
           && NILP (Fbitmap_spec_p (value)))
         signal_error ("Invalid stipple attribute", value);
@@ -4260,7 +4283,7 @@ FRAME 0 means change the face on all frames, and change the default
     }
   else if (EQ (attr, QCwidth))
     {
-      if (!UNSPECIFIEDP (value))
+      if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
         {
           CHECK_SYMBOL (value);
           if (face_numeric_swidth (value) < 0)
@@ -4285,7 +4308,7 @@ FRAME 0 means change the face on all frames, and change the default
           else
             f = check_x_frame (frame);
 
-          if (!UNSPECIFIEDP (value))
+          if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
             {
               CHECK_STRING (value);
 
@@ -4333,7 +4356,7 @@ FRAME 0 means change the face on all frames, and change the default
     signal_error ("Invalid face attribute name", attr);
 
   if (font_related_attr_p
-      && !UNSPECIFIEDP (value))
+      && !UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value))
     /* If a font-related attribute other than QCfont is specified, the
        original `font' attribute nor that of default face is useless
        to determine a new font.  Thus, we set it to nil so that font
@@ -4354,7 +4377,7 @@ FRAME 0 means change the face on all frames, and change the default
       ++windows_or_buffers_changed;
     }
 
-  if (!UNSPECIFIEDP (value)
+  if (!UNSPECIFIEDP (value) && !IGNORE_DEFFACE_P (value)
       && NILP (Fequal (old_value, value)))
     {
       Lisp_Object param;
@@ -8012,6 +8035,8 @@ syms_of_xfaces ()
   staticpro (&Qforeground_color);
   Qunspecified = intern ("unspecified");
   staticpro (&Qunspecified);
+  Qignore_defface = intern (":ignore-defface");
+  staticpro (&Qignore_defface);
 
   Qface_alias = intern ("face-alias");
   staticpro (&Qface_alias);