Re: Ibuffer as default

["Stefan Monnier" <monnier+gnu/emacs@rum.cs.yale.edu>]

> > I recently changed it to work better, especially for relatively
> > default cases like emacs -nw and Emacs under X with a left-sided
> > scrollbar and left-sided fringe (before it just used one space char
> > regardless).  But it seems doomed to lose given unusual settings.  Is
> > there a straight-forward way to cons up pixel-perfect spacing, say as
> > a display property ?
> 
> Yeah, given the popularity of using it for showing aligned stuff, there
> definitively should at least be an option for the header-line to start
> exactly at the text's left edge.  This could even be something as simple
> as a boolean variable I think, or a magic `%' escape in
> header-line-format.

Agreed.
BTW, I suspect that the `spaces' calculation should ideally
be enhanced to take into account window margins rather than only
scrollbars and fringes.... clearly this is a nightmare and should
be solved in a cleaner way.

> Stefan's problem (different font) seems a lot harder though...

How 'bout the patch below ?
Note that it doesn't address the problem of the leading space
being different in different frames and that it wouldn't be
able to use a % magic thingy either.


	Stefan


--- buff-menu.el.~1.60.~	Mon Mar 10 17:59:02 2003
+++ buff-menu.el	Mon Mar 10 18:49:43 2003
@@ -547,6 +547,9 @@
 		       ? )
 	  size))
 
+(defvar Buffer-menu-header-line nil)
+(put 'Buffer-menu-header-line 'risky-local-variable t)
+
 (defun list-buffers-noselect (&optional files-only)
   "Create and return a buffer with a list of names of existing buffers.
 The buffer is named `*Buffer List*'.
@@ -557,9 +560,31 @@
   (let* ((old-buffer (current-buffer))
 	 (standard-output standard-output)
 	 (mode-end (make-string (- Buffer-menu-mode-width 2) ? ))
-	 (header (concat "CRM " (Buffer-menu-buffer+size "Buffer" "Size")
+	 (header (concat (propertize "CRM " 'face 'fixed-pitch)
+			 (Buffer-menu-buffer+size "Buffer" "Size")
 			 "  Mode" mode-end "File\n"))
 	 list desired-point name file mode)
+    (when Buffer-menu-use-header-line
+      (let ((spaces
+	     (/ (+ 0.0 (or (frame-parameter nil 'left-fringe) 0)
+		   (or (if (eq (frame-parameter nil 'vertical-scroll-bars)
+			       'left)
+			   (frame-parameter nil 'scroll-bar-width))
+		       0))
+		(frame-char-width)))
+	    (pos 0))
+	;; Turn spaces in the header into stretch specs so they work
+	;; regardless of the header-line face.
+	(while (string-match "[ \t]+" header pos)
+	  (setq pos (match-end 0))
+	  (put-text-property (match-beginning 0) pos 'display
+			     ;; Assume fixed-size chars
+			     (list 'space :align-to (+ spaces pos))
+			     header))
+	;; Add the leading space
+	(setq header (concat (propertize (make-string (floor spaces) ? )
+					 'display (list 'space :width spaces))
+			     header))))
     (save-excursion
       (set-buffer (get-buffer-create "*Buffer List*"))
       (setq buffer-read-only nil)
@@ -639,15 +664,7 @@
 	(princ "\n"))
       (Buffer-menu-mode)
       (when Buffer-menu-use-header-line
-	(let ((spaces
-	       (/ (+ (or (frame-parameter nil 'left-fringe) 0)
-		     (or (if (eq (frame-parameter nil 'vertical-scroll-bars)
-				 'left)
-			     (frame-parameter nil 'scroll-bar-width))
-			 0))
-		  (frame-char-width))))
-	  (set (make-local-variable 'Buffer-menu-header-line)
-	       (concat (make-string spaces ? ) header)))
+	(set (make-local-variable 'Buffer-menu-header-line) header)
 	(setq header-line-format 'Buffer-menu-header-line))
       ;; DESIRED-POINT doesn't have to be set; it is not when the
       ;; current buffer is not displayed for some reason.