(Qauto_hscroll_mode): New var.

(syms_of_xdisp): Initialize it.
(hscroll_window_tree): Use it to lookup `auto-hscroll-mode' in each
window's buffer.
(hscroll_windows): Don't check automatic_hscrolling_p here.

2 files changed, 18 insertions, 15 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2f30dfcf807..3e11968fb58 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,11 @@
 2008-01-19  Stefan Monnier  <monnier@iro.umontreal.ca>
 
+        * xdisp.c (Qauto_hscroll_mode): New var.
+        (syms_of_xdisp): Initialize it.
+        (hscroll_window_tree): Use it to lookup `auto-hscroll-mode' in each
+        window's buffer.
+        (hscroll_windows): Don't check automatic_hscrolling_p here.
+
         * window.c (set_window_buffer): Don't unnecessarily reset hscroll and
         vscroll if we're setting window-buffer to the value it already has.
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 19ee4a0a92d..dfa18bfacb7 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -689,6 +689,7 @@ int trace_move;
    point visible.  */
 
 int automatic_hscrolling_p;
+Lisp_Object Qauto_hscroll_mode;
 
 /* How close to the margin can point get before the window is scrolled
    horizontally.  */
@@ -10381,11 +10382,12 @@ hscroll_window_tree (window)
           /* Scroll when cursor is inside this scroll margin.  */
           h_margin = hscroll_margin * WINDOW_FRAME_COLUMN_WIDTH (w);
 
-          if ((XFASTINT (w->hscroll)
-               && w->cursor.x <= h_margin)
-              || (cursor_row->enabled_p
-                  && cursor_row->truncated_on_right_p
-                  && (w->cursor.x >= text_area_width - h_margin)))
+          if (!NILP (Fbuffer_local_value (Qauto_hscroll_mode, w->buffer))
+              && ((XFASTINT (w->hscroll)
+                   && w->cursor.x <= h_margin)
+                  || (cursor_row->enabled_p
+                      && cursor_row->truncated_on_right_p
+                      && (w->cursor.x >= text_area_width - h_margin))))
             {
               struct it it;
               int hscroll;
@@ -10475,16 +10477,9 @@ static int
 hscroll_windows (window)
      Lisp_Object window;
 {
-  int hscrolled_p;
-
-  if (automatic_hscrolling_p)
-    {
-      hscrolled_p = hscroll_window_tree (window);
-      if (hscrolled_p)
-        clear_desired_matrices (XFRAME (WINDOW_FRAME (XWINDOW (window))));
-    }
-  else
-    hscrolled_p = 0;
+  int hscrolled_p = hscroll_window_tree (window);
+  if (hscrolled_p)
+    clear_desired_matrices (XFRAME (WINDOW_FRAME (XWINDOW (window))));
   return hscrolled_p;
 }
 
@@ -24387,6 +24382,8 @@ the frame's other specifications determine how to blink the cursor off.  */);
   DEFVAR_BOOL ("auto-hscroll-mode", &automatic_hscrolling_p,
     doc: /* *Non-nil means scroll the display automatically to make point visible.  */);
   automatic_hscrolling_p = 1;
+  Qauto_hscroll_mode = intern ("auto-hscroll-mode");
+  staticpro (&Qauto_hscroll_mode);
 
   DEFVAR_INT ("hscroll-margin", &hscroll_margin,
     doc: /* *How many columns away from the window edge point is allowed to get