Fix bug #6671 with recentering and other scrolling problems.

 src/xdisp.c (SCROLL_LIMIT): New macro.
 (try_scrolling): Use it when setting scroll_limit.  Limit
 scrolling to 100 screen lines.
 (redisplay_window): Even when falling back on "recentering",
 position point in the window according to scroll-conservatively,
 scroll-margin, and scroll-*-aggressively variables.
 (try_scrolling): When point is above the window, allow searching
 as far as scroll_max, or one screenful, to compute vertical
 distance from PT to the scroll margin position.  This prevents
 try_scrolling from unnecessarily failing when
 scroll-conservatively is set to a value slightly larger than the
 window height.  Clean up the case of PT below the margin at bottom
 of window: scroll_max can no longer be INT_MAX.  When aggressive
 scrolling is in use, don't let point enter the opposite scroll
 margin as result of the scroll.
 (syms_of_xdisp) <scroll-conservatively>: Document the
 threshold of 100 lines for never-recentering scrolling.

 doc/emacs/display.texi (Auto Scrolling): Document the limit of 100 lines
 for never-recentering scrolling with `scroll-conservatively'.

1 files changed, 26 insertions, 5 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c168a7133eb..98589b69cfb 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,29 @@
+2011-03-31  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (SCROLL_LIMIT): New macro.
+        (try_scrolling): Use it when setting scroll_limit.  Limit
+        scrolling to 100 screen lines.
+        (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 point is above the window, allow searching
+        as far as scroll_max, or one screenful, to compute vertical
+        distance from PT to the scroll margin position.  This prevents
+        try_scrolling from unnecessarily failing when
+        scroll-conservatively is set to a value slightly larger than the
+        window height.  Clean up the case of PT below the margin at bottom
+        of window: scroll_max can no longer be INT_MAX.  When aggressive
+        scrolling is in use, don't let point enter the opposite scroll
+        margin as result of the scroll.
+        (syms_of_xdisp) <scroll-conservatively>: Document the
+        threshold of 100 lines for never-recentering scrolling.
+
+2011-03-26  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (redisplay_window): Don't check buffer's clip_changed
+        flag as a prerequisite for invoking try_scrolling.  (Bug#6671)
+
 2011-03-31  Juanma Barranquero  <lekktu@gmail.com>
 
         * dispextern.h (move_it_by_lines):
@@ -184,11 +210,6 @@
         * s/usg5-4-common.h (SIGTYPE): Remove definition.
         * s/template.h (SIGTYPE): Remove commented out definition.
 
-2011-03-26  Eli Zaretskii  <eliz@gnu.org>
-
-        * xdisp.c (redisplay_window): Don't check buffer's clip_changed
-        flag as a prerequisite for invoking try_scrolling.  (Bug#6671)
-
 2011-03-26  Juanma Barranquero  <lekktu@gmail.com>
 
         * w32.c (read_unc_volume): Use parameter `henum', instead of