* simple.el (temporary-goal-column): Change the value for

line-move-visual to a cons cell.
(line-move-visual): Record or set the window hscroll, if
necessary (Bug#3494).
(line-move-1): Handle cons value of temporary-goal-column.

2 files changed, 43 insertions, 15 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index a1b44618e2c..007381ba11a 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,11 @@
+2009-07-11  Chong Yidong  <cyd@stupidchicken.com>
+
+        * simple.el (temporary-goal-column): Change the value for
+        line-move-visual to a cons cell.
+        (line-move-visual): Record or set the window hscroll, if
+        necessary (Bug#3494).
+        (line-move-1): Handle cons value of temporary-goal-column.
+
 2009-07-11  Kenichi Handa  <handa@m17n.org>
 
         * international/mule-diag.el (describe-character-set): Don't show
diff --git a/lisp/simple.el b/lisp/simple.el
index 0bdc21a75b0..15536bced08 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -3973,10 +3973,14 @@ This has no effect when `line-move-visual' is non-nil."
 (defvar temporary-goal-column 0
   "Current goal column for vertical motion.
 It is the column where point was at the start of the current run
-of vertical motion commands.  It is a floating point number when
-moving by visual lines via `line-move-visual'; this is the
-x-position, in pixels, divided by the default column width.  When
-the `track-eol' feature is doing its job, the value is
+of vertical motion commands.
+
+When moving by visual lines via `line-move-visual', it is a cons
+cell (COL . HSCROLL), where COL is the x-position, in pixels,
+divided by the default column width, and HSCROLL is the number of
+columns by which window is scrolled from left margin.
+
+When the `track-eol' feature is doing its job, the value is
 `most-positive-fixnum'.")
 
 (defcustom line-move-ignore-invisible t
@@ -4075,18 +4079,33 @@ into account variable-width characters and line continuation."
 (defun line-move-visual (arg &optional noerror)
   (let ((posn (posn-at-point))
         (opoint (point))
+        (hscroll (window-hscroll))
         x)
-    ;; Reset temporary-goal-column, unless the previous command was a
-    ;; line-motion command or we were called from some other command.
-    (unless (and (floatp temporary-goal-column)
-                 (memq last-command `(next-line previous-line ,this-command)))
-      (cond ((eq (nth 1 posn) 'right-fringe) ; overflow-newline-into-fringe
-             (setq temporary-goal-column (- (window-width) 1)))
-            ((setq x (car (posn-x-y posn)))
-             (setq temporary-goal-column (/ (float x) (frame-char-width))))))
+    ;; Check if the previous command was a line-motion command, or if
+    ;; we were called from some other command.
+    (cond ((and (consp temporary-goal-column)
+                (memq last-command `(next-line previous-line ,this-command)))
+           ;; If so, there's no need to reset `temporary-goal-column',
+           ;; unless the window hscroll has changed.
+           (when (/= hscroll (cdr temporary-goal-column))
+             (set-window-hscroll nil 0)
+             (setq temporary-goal-column
+                   (cons (+ (car temporary-goal-column)
+                            (cdr temporary-goal-column)) 0))))
+          ;; Otherwise, we should reset `temporary-goal-column'.
+          ;; Handle the `overflow-newline-into-fringe' case:
+          ((eq (nth 1 posn) 'right-fringe)
+           (setq temporary-goal-column (cons (- (window-width) 1) hscroll)))
+          ((setq x (car (posn-x-y posn)))
+           (setq temporary-goal-column
+                 (cons (/ (float x) (frame-char-width)) hscroll))))
     ;; Move using `vertical-motion'.
     (or (and (= (vertical-motion
-                 (cons (or goal-column (truncate temporary-goal-column)) arg))
+                 (cons (or goal-column
+                           (if (consp temporary-goal-column)
+                               (truncate (car temporary-goal-column))
+                             temporary-goal-column))
+                       arg))
                 arg)
              (or (>= arg 0)
                  (/= (point) opoint)
@@ -4108,8 +4127,9 @@ into account variable-width characters and line continuation."
   (let ((inhibit-point-motion-hooks t)
         (opoint (point))
         (orig-arg arg))
-    (if (floatp temporary-goal-column)
-        (setq temporary-goal-column (truncate temporary-goal-column)))
+    (if (consp temporary-goal-column)
+        (setq temporary-goal-column (+ (car temporary-goal-column)
+                                       (cdr temporary-goal-column))))
     (unwind-protect
         (progn
           (if (not (memq last-command '(next-line previous-line)))