From c7e73d5177c6b51d8453830b6400090cc1a052df Mon Sep 17 00:00:00 2001
From: Glenn Morris <rgm@gnu.org>
Date: Thu, 15 Mar 2012 21:10:46 -0400
Subject: [PATCH] calendar-insert-at-column small fix for bug#10978

* lisp/calendar/calendar.el (calendar-insert-at-column):
Handle non-unit-width characters a bit better.
---
 lisp/ChangeLog            |  5 +++++
 lisp/calendar/calendar.el | 22 +++++++++++++++-------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 427d7d8797..1e1f02f2cd 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2012-03-16  Glenn Morris  <rgm@gnu.org>
+
+	* calendar/calendar.el (calendar-insert-at-column):
+	Handle non-unit-width characters a bit better.  (Bug#10978)
+
 2012-03-15  Chong Yidong  <cyd@gnu.org>
 
 	* emacs-lisp/ring.el (ring-extend): New function.
diff --git a/lisp/calendar/calendar.el b/lisp/calendar/calendar.el
index b09167ea49..d9ec27b4f8 100644
--- a/lisp/calendar/calendar.el
+++ b/lisp/calendar/calendar.el
@@ -1424,16 +1424,24 @@ Optional integers MON and YR are used instead of today's date."
   "Move to column INDENT, adding spaces as needed.
 Inserts STRING so that it ends at INDENT.  STRING is either a
 literal string, or a sexp to evaluate to return such.  Truncates
-STRING to length TRUNCATE, ensure a trailing space."
+STRING to length TRUNCATE, and ensures a trailing space."
   (if (not (ignore-errors (stringp (setq string (eval string)))))
       (calendar-move-to-column indent)
-    (if (> (length string) truncate)
-        (setq string (substring string 0 truncate)))
+    (if (> (string-width string) truncate)
+        (setq string (truncate-string-to-width string truncate)))
     (or (string-match " $" string)
-        (if (= (length string) truncate)
-            (aset string (1- truncate) ?\s)
-          (setq string (concat string " "))))
-    (calendar-move-to-column (- indent (length string)))
+        (setq string (concat (if (= (string-width string) truncate)
+                                 (substring string 0 -1)
+                               string)
+                             ;; Avoid inserting text properties unless
+                             ;; we have to (ie, non-unit-width chars).
+                             ;; This is by no means essential.
+                             (if (= (string-width string) (length string))
+                                 " "
+                               ;; Cribbed from buff-menu.el.
+                               (propertize
+                                " " 'display `(space :align-to ,indent))))))
+    (calendar-move-to-column (- indent (string-width string)))
     (insert string)))
 
 (defun calendar-generate-month (month year indent)
-- 
2.20.1