Fix line-move-visual's following of column in R2L lines.

 src/simple.el (line-move-visual): When converting X pixel coordinate
 to temporary-goal-column, adjust the value for right-to-left
 screen lines.  This fixes vertical-motion, next/prev-line, etc.

 src/dispnew.c (buffer_posn_from_coords): Fix the value of the column
 returned for right-to-left screen lines.  (Before the change on
 2014-12-30, the incorrectly-computed X pixel coordinate concealed
 this bug.)

lisp/ChangeLog

+2015-01-08  Eli Zaretskii  <eliz@gnu.org>
+
+	* simple.el (line-move-visual): When converting X pixel coordinate
+	to temporary-goal-column, adjust the value for right-to-left
+	screen lines.  This fixes vertical-motion, next/prev-line, etc.
+
 2015-01-08  Glenn Morris  <rgm@gnu.org>
 	* files.el (file-tree-walk): Remove; of unknown authorship.  (Bug#19325)

lisp/simple.el

@@ -5604,14 +5604,22 @@ If NOERROR, don't signal an error if we can't move that many lines."
 		(>  (cdr temporary-goal-column) 0))
 	    (setq target-hscroll (cdr temporary-goal-column)))
       ;; Otherwise, we should reset `temporary-goal-column'.
-      (let ((posn (posn-at-point)))
+      (let ((posn (posn-at-point))
+	    x-pos)
 	(cond
 	 ;; Handle the `overflow-newline-into-fringe' case:
 	 ((eq (nth 1 posn) 'right-fringe)
 	  (setq temporary-goal-column (cons (- (window-width) 1) hscroll)))
 	 ((car (posn-x-y posn))
+	  (setq x-pos (car (posn-x-y posn)))
+	  ;; In R2L lines, the X pixel coordinate is measured from the
+	  ;; left edge of the window, but columns are still counted
+	  ;; from the logical-order beginning of the line, i.e. from
+	  ;; the right edge in this case.  We need to adjust for that.
+	  (if (eq (current-bidi-paragraph-direction) 'right-to-left)
+	      (setq x-pos (- (window-body-width nil t) 1 x-pos)))
 	  (setq temporary-goal-column
-		(cons (/ (float (car (posn-x-y posn)))
+		(cons (/ (float x-pos)
 			 (frame-char-width))
                       hscroll))))))
     (if target-hscroll

src/ChangeLog

 2015-01-08  Eli Zaretskii  <eliz@gnu.org>
+	* dispnew.c (buffer_posn_from_coords): Fix the value of the column
+	returned for right-to-left screen lines.  (Before the change on
+	2014-12-30, the incorrectly-computed X pixel coordinate concealed
+	this bug.)
+
 	* .gdbinit (xsymname): New subroutine.
 	(xprintsym, initial-tbreak): Use it to access the name of a symbol
 	in a way that doesn't cause GDB to barf when it tries to

src/dispnew.c

@@ -5162,7 +5162,7 @@ buffer_posn_from_coords (struct window *w, int *x, int *y, struct display_pos *p
 
   Fset_buffer (old_current_buffer);
 
-  *dx = x0 + it.first_visible_x - it.current_x;
+  *dx = to_x - it.current_x;
   *dy = *y - it.current_y;
 
   string = w->contents;
@@ -5237,9 +5237,9 @@ buffer_posn_from_coords (struct window *w, int *x, int *y, struct display_pos *p
     }
 
   /* Add extra (default width) columns if clicked after EOL. */
-  x1 = max (0, it.current_x + it.pixel_width - it.first_visible_x);
-  if (x0 > x1)
-    it.hpos += (x0 - x1) / WINDOW_FRAME_COLUMN_WIDTH (w);
+  x1 = max (0, it.current_x + it.pixel_width);
+  if (to_x > x1)
+    it.hpos += (to_x - x1) / WINDOW_FRAME_COLUMN_WIDTH (w);
 
   *x = it.hpos;
   *y = it.vpos;