Prevent unnecessary scrolling in bidi-reordered buffers.

 xdisp.c (try_cursor_movement): back up to non-continuation line only
 after finding point's row..

2 files changed, 36 insertions, 27 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index eeee6540e68..a530e844bf9 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-05-28  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (try_cursor_movement): Prevent unnecessary scrolling in
+        bidi-reordered buffers.
+
 2010-05-28  Kenichi Handa  <handa@m17n.org>
 
         * font.c (font_delete_unmatched): Check Vface_ignored_fonts.
diff --git a/src/xdisp.c b/src/xdisp.c
index 31fa5f39d5f..a94049a780b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -13763,32 +13763,6 @@ try_cursor_movement (window, startp, scroll_step)
             ++row;
           if (!row->enabled_p)
             rc = CURSOR_MOVEMENT_MUST_SCROLL;
-          /* If rows are bidi-reordered, back up until we find a row
-             that does not belong to a continuation line.  This is
-             because we must consider all rows of a continued line as
-             candidates for cursor positioning, since row start and
-             end positions change non-linearly with vertical position
-             in such rows.  */
-          /* FIXME: Revisit this when glyph ``spilling'' in
-             continuation lines' rows is implemented for
-             bidi-reordered rows.  */
-          if (!NILP (XBUFFER (w->buffer)->bidi_display_reordering))
-            {
-              while (MATRIX_ROW_CONTINUATION_LINE_P (row))
-                {
-                  xassert (row->enabled_p);
-                  --row;
-                  /* If we hit the beginning of the displayed portion
-                     without finding the first row of a continued
-                     line, give up.  */
-                  if (row <= w->current_matrix->rows)
-                    {
-                      rc = CURSOR_MOVEMENT_MUST_SCROLL;
-                      break;
-                    }
-
-                }
-            }
         }
 
       if (rc == CURSOR_MOVEMENT_CANNOT_BE_USED)
@@ -13888,7 +13862,37 @@ try_cursor_movement (window, startp, scroll_step)
               rc = CURSOR_MOVEMENT_MUST_SCROLL;
             }
           else if (rc != CURSOR_MOVEMENT_SUCCESS
-                   && MATRIX_ROW_PARTIALLY_VISIBLE_P (w, row)
+                   && !NILP (XBUFFER (w->buffer)->bidi_display_reordering))
+            {
+              /* If rows are bidi-reordered and point moved, back up
+                 until we find a row that does not belong to a
+                 continuation line.  This is because we must consider
+                 all rows of a continued line as candidates for the
+                 new cursor positioning, since row start and end
+                 positions change non-linearly with vertical position
+                 in such rows.  */
+              /* FIXME: Revisit this when glyph ``spilling'' in
+                 continuation lines' rows is implemented for
+                 bidi-reordered rows.  */
+              while (MATRIX_ROW_CONTINUATION_LINE_P (row))
+                {
+                  xassert (row->enabled_p);
+                  --row;
+                  /* If we hit the beginning of the displayed portion
+                     without finding the first row of a continued
+                     line, give up.  */
+                  if (row <= w->current_matrix->rows)
+                    {
+                      rc = CURSOR_MOVEMENT_CANNOT_BE_USED;
+                      break;
+                    }
+
+                }
+            }
+          if (rc == CURSOR_MOVEMENT_SUCCESS
+              || rc == CURSOR_MOVEMENT_CANNOT_BE_USED)
+            ;
+          else if (MATRIX_ROW_PARTIALLY_VISIBLE_P (w, row)
                    && make_cursor_line_fully_visible_p)
             {
               if (PT == MATRIX_ROW_END_CHARPOS (row)