[Emacs-diffs] Changes to emacs/lispref/display.texi

[Chong Yidong]

Index: emacs/lispref/display.texi
diff -c emacs/lispref/display.texi:1.193 emacs/lispref/display.texi:1.194
*** emacs/lispref/display.texi:1.193    Sun Oct 23 18:18:11 2005
--- emacs/lispref/display.texi  Fri Nov 18 02:51:12 2005
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*** 1859,1864 ****
--- 1859,1869 ----
  next face gets a chance.  However, the @code{default} face must
  specify all attributes.
  
+   Any attribute can have the value @code{:ignore-defface}.  The effect
+ of this is identical to @code{unspecified}.  It exists because of an
+ technical ambiguity in giving attributes the value @code{unspecified}.
+ @xref{Attribute Functions}.
+ 
    Some of these font attributes are meaningful only on certain kinds of
  displays---if your display cannot handle a certain attribute, the
  attribute is ignored.  (The attributes @code{:family}, @code{:width},
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*** 2050,2055 ****
--- 2055,2068 ----
  This function sets one or more attributes of face @var{face}
  for frame @var{frame}.  If @var{frame} is @code{nil}, it sets
  the attribute for all frames, and the defaults for new frames.
+ 
+ Unless you know what you're doing, don't set an attribute to
+ @code{unspecified}.  This is ambiguous---it is unclear whether it
+ means to unspecify the value stored in the frame-local copies of the
+ face (which means reverting to the original face spec), or the value
+ in the face spec itself.  What you probably want is to set the
+ attribute to @code{:ignore-defface}.  This forces the attribute value
+ to be acquired from some other face during face merging.
  
  The extra arguments @var{arguments} specify the attributes to set, and
  the values for them.  They should consist of alternating attribute names