Re: describe-face should show an example of text in the face.

[Yoni Rabkin Katzenell]

"Drew Adams" <address@hidden> writes:

>     > Good idea. How about showing two samples: foreground and background?
>
>     Like in `list-colors-display'? If that is not what you mean then I am
>     misunderstanding you.
>
> Yes, that's what I was thinking.
>
> But I was mistakenly thinking of colors, not faces. Please ignore my
> suggestion.

Your reply got me thinking. 

The following patch does exactly the same, except that it renders the
"sample" text to look just like the "sample" text in the `customize'
buffer. So that both are visually consistent examples.

The following screenshot shows how `describe-face' looks with the
attached patch, as compared with the `customize' buffer:

http://yrk.nfshost.com/images/faces-sample.png

Index: faces.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/faces.el,v
retrieving revision 1.354
diff -u -r1.354 faces.el
--- faces.el    14 Sep 2006 23:54:44 -0000      1.354
+++ faces.el    16 Oct 2006 19:52:28 -0000
@@ -32,6 +32,9 @@
   ;; Warning suppression -- can't require x-win in batch:
   (autoload 'xw-defined-colors "x-win"))
 
+(defvar faces-sample-overlay nil
+  "Overlay for showing an example of a face.")
+
 (defvar help-xref-stack-item)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -1253,6 +1256,17 @@
            (setq faces (cdr faces)))))))
 
 
+(defun faces-sample-overlay (face)
+  "Insert sample text with FACE.
+
+If FACE is not a face or nil, use the default face."
+  (let ((f (if (facep face) face 'default))
+       (start (+ (point) 2))) ;; +1 to skip leading space
+    (insert " (sample)")
+    (setq faces-sample-overlay (make-overlay start (1- (point))))
+    (overlay-put faces-sample-overlay 'face f)))
+
+
 (defun describe-face (face &optional frame)
   "Display the properties of face FACE on FRAME.
 Interactively, FACE defaults to the faces of the character after point
@@ -1293,6 +1307,7 @@
              (insert "   undefined face.\n")
            (let ((customize-label "customize this face")
                  file-name)
+             (faces-sample-overlay f)
              (princ (concat " (" customize-label ")\n"))
              (insert "Documentation: "
                      (or (face-documentation f)


-- 
   "Cut your own wood and it will warm you twice"