org-indent: Fix indentation with proportional font

* lisp/org-indent.el (org-indent-max):
(org-indent-max-levels):
(org-indent-strings):
(org-indent-stars): Remove unused variables.

(org-indent-initialize): Remove function.

(org-indent-boundary-char): Remove unnecessary comment.  Do not rely on
function above.

(org-indent): Make sure characters used for virtual indentation are
invisible since they are not necessarily white spaces.

(org-indent-set-line-properties): Fix indentation with proportional
font, i.e., do not use only white spaces to indent.
(org-indent-add-properties): Apply changes above.

Reported-by: Jakub Szypulka <jakub@szypulka.de>
<http://permalink.gmane.org/gmane.emacs.orgmode/100252>

lisp/org-indent.el

@@ -52,20 +52,6 @@
   :tag "Org Indent"
   :group 'org)
 
-(defconst org-indent-max 40
-  "Maximum indentation in characters.")
-(defconst org-indent-max-levels 20
-  "Maximum added level through virtual indentation, in characters.
-
-It is computed by multiplying `org-indent-indentation-per-level'
-minus one by actual level of the headline minus one.")
-
-(defvar org-indent-strings nil
-  "Vector with all indentation strings.
-It will be set in `org-indent-initialize'.")
-(defvar org-indent-stars nil
-  "Vector with all indentation star strings.
-It will be set in `org-indent-initialize'.")
 (defvar org-indent-inlinetask-first-star (org-add-props "*" '(face org-warning))
   "First star of inline tasks, with correct face.")
 (defvar org-indent-agent-timer nil
@@ -92,15 +78,12 @@ This is used locally in each buffer being initialized.")
 It is modified by `org-indent-notify-modified-headline'.")
 
 
-(defcustom org-indent-boundary-char ?\   ; comment to protect space char
+(defcustom org-indent-boundary-char ?\s
   "The end of the virtual indentation strings, a single-character string.
 The default is just a space, but if you wish, you can use \"|\" or so.
 This can be useful on a terminal window - under a windowing system,
-it may be prettier to customize the org-indent face."
+it may be prettier to customize the `org-indent' face."
   :group 'org-indent
-  :set (lambda (var val)
-	 (set var val)
-	 (and org-indent-strings (org-indent-initialize)))
   :type 'character)
 
 (defcustom org-indent-mode-turns-off-org-adapt-indentation t
@@ -121,30 +104,12 @@ turn on `org-hide-leading-stars'."
   :group 'org-indent
   :type 'integer)
 
-(defface org-indent
-  (org-compatible-face nil nil)
+(defface org-indent '((t (:inherit org-hide)))
   "Face for outline indentation.
 The default is to make it look like whitespace.  But you may find it
 useful to make it ever so slightly different."
   :group 'org-faces)
 
-(defun org-indent-initialize ()
-  "Initialize the indentation strings."
-  (setq org-indent-strings (make-vector (1+ org-indent-max) nil))
-  (setq org-indent-stars (make-vector (1+ org-indent-max) nil))
-  (aset org-indent-strings 0 nil)
-  (aset org-indent-stars 0 nil)
-  (loop for i from 1 to org-indent-max do
-	(aset org-indent-strings i
-	      (org-add-props
-		  (concat (make-string (1- i) ?\ )
-			  (char-to-string org-indent-boundary-char))
-		  nil 'face 'org-indent)))
-  (loop for i from 1 to org-indent-max-levels do
-	(aset org-indent-stars i
-	      (org-add-props (make-string i ?*)
-		  nil 'face 'org-hide))))
-
 (defsubst org-indent-remove-properties (beg end)
   "Remove indentations between BEG and END."
   (org-with-silent-modifications
@@ -174,7 +139,6 @@ during idle time."
    (org-indent-mode
     ;; mode was turned on.
     (org-set-local 'indent-tabs-mode nil)
-    (or org-indent-strings (org-indent-initialize))
     (org-set-local 'org-indent-initial-marker (copy-marker 1))
     (when org-indent-mode-turns-off-org-adapt-indentation
       (org-set-local 'org-adapt-indentation nil))
@@ -281,34 +245,40 @@ a time value."
 	   (setq org-indent-agentized-buffers
 		 (delq buffer org-indent-agentized-buffers))))))))
 
-(defsubst org-indent-set-line-properties (l w h)
+(defun org-indent-set-line-properties (level indentation &optional heading)
   "Set prefix properties on current line an move to next one.
 
-Prefix properties `line-prefix' and `wrap-prefix' in current line
-are set to, respectively, length L and W.
-
-If H is non-nil, `line-prefix' will be starred.  If H is
-`inline', the first star will have `org-warning' face.
-
-Assume point is at beginning of line."
-  (let ((line (cond
-	       ((eq 'inline h)
-		(let ((stars (aref org-indent-stars
-				   (min l org-indent-max-levels))))
-		  (and stars
-		       (if (org-bound-and-true-p org-inlinetask-show-first-star)
-			   (concat org-indent-inlinetask-first-star
-				   (substring stars 1))
-			 stars))))
-	       (h (aref org-indent-stars
-			(min l org-indent-max-levels)))
-	       (t (aref org-indent-strings
-			(min l org-indent-max)))))
-	(wrap (aref org-indent-strings (min w org-indent-max))))
+LEVEL is the current level of heading.  INDENTATION is the
+expected indentation when wrapping line.
+
+When optional argument HEADING is non-nil, assume line is at
+a heading.  Moreover, if is is `inlinetask', the first star will
+have `org-warning' face."
+  (let* ((stars (if (<= level 1) ""
+		  (make-string (* org-indent-indentation-per-level
+				  (1- level))
+			       ?*)))
+	 (line
+	  (cond
+	   ((and (org-bound-and-true-p org-inlinetask-show-first-star)
+		 (eq heading 'inlinetask))
+	    (concat org-indent-inlinetask-first-star
+		    (org-add-props (substring stars 1) nil 'face 'org-hide)))
+	   (heading (org-add-props stars nil 'face 'org-hide))
+	   (t (concat (org-add-props (concat stars (make-string level ?*))
+			  nil 'face 'org-indent)
+		      (char-to-string org-indent-boundary-char)))))
+	 (wrap
+	  (org-add-props
+	      (concat stars
+		      (make-string level ?*)
+		      (if heading " "
+			(make-string (+ indentation (min level 1)) ?\s)))
+	      nil 'face 'org-indent)))
     ;; Add properties down to the next line to indent empty lines.
-    (add-text-properties (point) (min (1+ (point-at-eol)) (point-max))
+    (add-text-properties (line-beginning-position) (line-beginning-position 2)
 			 `(line-prefix ,line wrap-prefix ,wrap)))
-  (forward-line 1))
+  (forward-line))
 
 (defun org-indent-add-properties (beg end &optional delay)
   "Add indentation properties between BEG and END.
@@ -328,12 +298,10 @@ stopped."
      ;;    inline task or not.
      (let* ((case-fold-search t)
 	    (limited-re (org-get-limited-outline-regexp))
-	    (added-ind-per-lvl (abs (1- org-indent-indentation-per-level)))
 	    (pf (save-excursion
 		  (and (ignore-errors (let ((outline-regexp limited-re))
 					(org-back-to-heading t)))
-		       (+ (* org-indent-indentation-per-level
-			     (- (match-end 0) (match-beginning 0) 2)) 2))))
+		       (- (match-end 0) (match-beginning 0) 1))))
 	    (pf-inline (and (featurep 'org-inlinetask)
 			    (org-inlinetask-in-task-p)
 			    (+ (* org-indent-indentation-per-level
@@ -354,38 +322,36 @@ stopped."
 	   ((and delay (time-less-p time-limit (current-time)))
 	    (setq org-indent-agent-resume-timer
 		  (run-with-idle-timer
-		   (time-add (current-idle-time)
-			     org-indent-agent-resume-delay)
+		   (time-add (current-idle-time) org-indent-agent-resume-delay)
 		   nil #'org-indent-initialize-agent))
 	    (throw 'interrupt (point)))
 	   ;; Headline or inline task.
 	   ((looking-at org-outline-regexp)
-	    (let* ((nstars (- (match-end 0) (match-beginning 0) 1))
-		   (line (* added-ind-per-lvl (1- nstars)))
-		   (wrap (+ line (1+ nstars))))
+	    (let* ((nstars (- (match-end 0) (match-beginning 0) 1)))
 	      (cond
 	       ;; Headline: new value for PF.
 	       ((looking-at limited-re)
-		(org-indent-set-line-properties line wrap t)
-		(setq pf wrap))
+		(org-indent-set-line-properties nstars 0 t)
+		(setq pf nstars))
 	       ;; End of inline task: PF-INLINE is now nil.
 	       ((looking-at "\\*+ end[ \t]*$")
-		(org-indent-set-line-properties line wrap 'inline)
+		(org-indent-set-line-properties nstars 0 'inlinetask)
 		(setq pf-inline nil))
 	       ;; Start of inline task.  Determine if it contains
 	       ;; text, or if it is only one line long.  Set
 	       ;; PF-INLINE accordingly.
-	       (t (org-indent-set-line-properties line wrap 'inline)
-		  (setq pf-inline (and (org-inlinetask-in-task-p) wrap))))))
+	       (t (org-indent-set-line-properties nstars 0 'inlinetask)
+		  (setq pf-inline (and (org-inlinetask-in-task-p) nstars))))))
 	   ;; List item: `wrap-prefix' is set where body starts.
 	   ((org-at-item-p)
 	    (let* ((line (or pf-inline pf 0))
-		   (wrap (+ (org-list-item-body-column (point)) line)))
-	      (org-indent-set-line-properties line wrap nil)))
+		   (wrap (org-list-item-body-column (point))))
+	      (org-indent-set-line-properties
+	       (or pf-inline pf 0)
+	       (org-list-item-body-column (point)))))
 	   ;; Normal line: use PF-INLINE, PF or nil as prefixes.
-	   (t (let* ((line (or pf-inline pf 0))
-		     (wrap (+ line (org-get-indentation))))
-		(org-indent-set-line-properties line wrap nil))))))))))
+	   (t (org-indent-set-line-properties
+	       (or pf-inline pf 0) (org-get-indentation))))))))))
 
 (defun org-indent-notify-modified-headline (beg end)
   "Set `org-indent-modified-headline-flag' depending on context.