Clarify the :box attributes in Face Attributes lispref node

* doc/lispref/display.texi (Face Attributes): Mention that the
elements are optional (bug#50699).

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index fde7274d591df6e08563782c0403b5aad9444264..bb2b2d98a36a90c96237084383e962a1ee39581b 100644 (file)
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -2623,14 +2623,17 @@ Draw a box with lines of width 1, in the foreground color.
 Draw a box with lines of width 1, in color @var{color}.
 
 @item @code{(:line-width (@var{vwidth} . @var{hwidth}) :color @var{color} :style @var{style})}
-This way you can explicitly specify all aspects of the box.  The values
-@var{vwidth} and @var{hwidth} specifies respectively the width of the
-vertical and horizontal lines to draw; they default to (1 . 1).
-A negative horizontal or vertical width @minus{}@var{n} means to draw a line
-of width @var{n} that occupies the space of the underlying text, thus
-avoiding any increase in the character height or width. For simplification
-the width could be specified with only a single number @var{n} instead
-of a list, such case is equivalent to @code{((abs @var{n}) . @var{n})}.
+You can explicitly specify all aspects of the box with a plist on this
+form.  Any element in this plist can be omitted.
+
+The values @var{vwidth} and @var{hwidth} specifies respectively the
+width of the vertical and horizontal lines to draw; they default to (1
+. 1).  A negative horizontal or vertical width @minus{}@var{n} means
+to draw a line of width @var{n} that occupies the space of the
+underlying text, thus avoiding any increase in the character height or
+width. For simplification the width could be specified with only a
+single number @var{n} instead of a list, such case is equivalent to
+@code{((abs @var{n}) . @var{n})}.
 
 The value @var{style} specifies whether to draw a 3D box.  If it is
 @code{released-button}, the box looks like a 3D button that is not