Fix scrolling with scroll-*-aggressively.

Aggressive scrolling backward by large distance still doesn't DTRT.

 src/xdisp.c (try_scrolling): When aggressive scrolling is in use, don't
 let point enter the opposite scroll margin as result of the scroll.
 (redisplay_window): Fix operator precedence in condition.

2 files changed, 13 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ef3a1546913..d4301c482e9 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -8,6 +8,9 @@
         (redisplay_window): Even when falling back on "recentering",
         position point in the window according to scroll-conservatively,
         scroll-margin, and scroll-*-aggressively variables.  (Bug#6671)
+        (try_scrolling): When aggressive scrolling is in use, don't let
+        point enter the opposite scroll margin as result of the scroll.
+        (redisplay_window): Fix operator precedence in condition.
 
 2011-03-26  Juanma Barranquero  <lekktu@gmail.com>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 263bedec4a2..230e2fa1864 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13125,6 +13125,10 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
               amount_to_scroll = float_amount;
               if (amount_to_scroll == 0 && float_amount > 0)
                 amount_to_scroll = 1;
+              /* Don't let point enter the scroll margin near top of
+                 the window.  */
+              if (amount_to_scroll > height - 2*this_scroll_margin + dy)
+                amount_to_scroll = height - 2*this_scroll_margin + dy;
             }
         }
 
@@ -13208,6 +13212,11 @@ try_scrolling (Lisp_Object window, int just_this_one_p,
                   amount_to_scroll = float_amount;
                   if (amount_to_scroll == 0 && float_amount > 0)
                     amount_to_scroll = 1;
+                  amount_to_scroll -= this_scroll_margin - dy;
+                  /* Don't let point enter the scroll margin near
+                     bottom of the window.  */
+                  if (amount_to_scroll > height - 2*this_scroll_margin + dy)
+                    amount_to_scroll = height - 2*this_scroll_margin + dy;
                 }
             }
 
@@ -14236,7 +14245,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
         : BVAR (current_buffer, scroll_down_aggressively);
 
       if (!MINI_WINDOW_P (w)
-          && scroll_conservatively > SCROLL_LIMIT || NUMBERP (aggressive))
+          && (scroll_conservatively > SCROLL_LIMIT || NUMBERP (aggressive)))
         {
           int pt_offset = 0;