Fix bug #10129: add positional information to "C-u C-x =".

[bpt/emacs.git] / lisp / descr-text.el

diff --git a/lisp/descr-text.el b/lisp/descr-text.el
index 9aa061b..d2995ab 100644 (file)
--- a/lisp/descr-text.el
+++ b/lisp/descr-text.el
@@ -376,12 +376,21 @@ This function is semi-obsolete.  Use `get-char-code-property'."
 
 ;;;###autoload
 (defun describe-char (pos &optional buffer)
-  "Describe the character after POS (interactively, the character after point).
-Is POS is taken to be in buffer BUFFER or current buffer if nil.
-The information includes character code, charset and code points in it,
-syntax, category, how the character is encoded in a file,
-character composition information (if relevant),
-as well as widgets, buttons, overlays, and text properties."
+  "Describe position POS (interactively, point) and the char after POS.
+POS is taken to be in BUFFER, or the current buffer if BUFFER is nil.
+The information is displayed in buffer `*Help*'.
+
+The position information includes POS; the total size of BUFFER; the
+region limits, if narrowed; the column number; and the horizontal
+scroll amount, if the buffer is horizontally scrolled.
+
+The character information includes the character code; charset and
+code points in it; syntax; category; how the character is encoded in
+BUFFER and in BUFFER's file; character composition information (if
+relevant); the font and font glyphs used to display the character;
+the character's canonical name and other properties defined by the
+Unicode Data Base; and widgets, buttons, overlays, and text properties
+relevant to POS."
   (interactive "d")
   (unless (buffer-live-p buffer) (setq buffer (current-buffer)))
   (let ((src-buf (current-buffer)))
@@ -511,7 +520,25 @@ as well as widgets, buttons, overlays, and text properties."
             (setq composition nil)))
 
       (setq item-list
-            `(("character"
+            `(("position"
+               ,(let* ((beg      (point-min))
+                       (end      (point-max))
+                       (total    (buffer-size))
+                       (percent  (if (> total 50000) ; Avoid overflow multiplying by 100
+                                     (/ (+ (/ total 200) (1- pos))  (max (/ total 100) 1))
+                                   (/ (+ (/ total 2) (* 100 (1- pos)))  (max total 1))))
+                       (hscroll  (if (= (window-hscroll) 0)
+                                     ""
+                                   (format ", Hscroll: %d" (window-hscroll))))
+                       (col      (current-column)))
+                  (if (or (/= beg 1)  (/= end (1+ total)))
+                      (format "%d of %d (%d%%), restriction: <%d-%d>, column: %d%s"
+                              pos total percent col beg end hscroll)
+                    (if (= pos end)
+                        (format "%d of %d (EOB), column: %d%s" pos total col hscroll)
+                      (format "%d of %d (%d%%), column: %d%s"
+                              pos total percent col hscroll)))))
+              ("character"
                ,(format "%s (displayed as %s) (codepoint %d, #o%o, #x%x)"
                        char-description
                         (apply 'propertize char-description
@@ -522,7 +549,7 @@ as well as widgets, buttons, overlays, and text properties."
                   ,(symbol-name charset)
                   'type 'help-character-set 'help-args '(,charset))
                ,(format "(%s)" (charset-description charset)))
-              ("code point"
+              ("code point in charset"
                ,(let ((str (if (integerp code)
                                (format (if (< code 256) "0x%02X" "0x%04X")
                                        code)